22nd EDITION

4

4

POWER SUPPLIES

ANALOG

DESIGN GUIDE

Data Sheets

Applications Notes

Free Samples

•

•

ANALOG

DESIGN GUIDE

1
2
3

4

5
6
7
8
9

10
11

Multiplexers, Switches

DC-DC Converters,
Power Supplies

High-Speed
ADCs & DACs

Signal Conditioners

Video/High-Speed Amps

Interface Products

Op Amps, Comparators

µP Supervisory
Analog Filters

A/D Converters

D/A Converters

Analog Functions

Voltage References

Temperature Sensors

12

13

14

Smallest Dual-Output Supply
for PDAs: Logic Step-Down and
LCD Step-Up

High-Efficiency Hand-Held Supply Fits Internal Switches into a
12-Pin QFN Package

• Dual-Output:

• Step-Down: Logic Supply Down

to 1.25V

• Step-Up: LCD Supply Up to 28V

• Smallest Package: 4mm x 4mm

12-Pin QFN

• Small External Components:

10µF and 10µH

• 90% Efficiency

• Low 19µA Quiescent

Supply Current

• Evaluation Kit

Available to Speed
Designs

• Priced at $1.57

†

MAX1878

PGND AGND

INPUT

2.0V TO 5.5V

PGNDLCD

10

µH

10

µH

ON

OFF

FB

LX

FBLCD

LXLCD

AIN1

AIN2

IN

ONLCD

ON

ON

OFF

LOGIC

LCD

LOGIC OUTPUT

1.25V TO V

IN

UP TO 500mA

0.1

µF

LCD OUTPUT

UP TO 28V

UP TO 10mA

4

m

m

x

4 m m x 0

.8

5

m

m

12

-PIN QFN

Packaged in a 0.85mm high, 4mm x 4mm QFN, the MAX1878 is the

simplest and smallest single-chip solution providing both logic and LCD
power for PDAs and hand-held products. For the logic supply, it uses a
high-efficiency (90%) step-down DC-DC converter with synchronous rectifi-
cation that eliminates the need for an external diode, saving cost and size.
For the LCD supply, the internal switch is capable of supplying outputs as
high as 28V. Each output has its own logic-controlled enable.

†1000-up recommended resale. Price provided is for design guidance and is FOB USA. International prices will differ due to local duties,
taxes, and exchange rates. Not all packages are offered in 1k increments, and some may require minimum order quantities.

STEPS DOWN TO 1.25V FOR NEWEST LOGIC CHIPS

is a registered trademark of Maxim Integrated Products, Inc. © 2002 Maxim Integrated Products.

P

V

IN

V

IN

N

N

V

IN

N

MAX1801

V

IN

N

ON

OFF

OUT1

LDO

OUT2

STEP-UP

MASTER

OUT3

OUT4

OSC

REF

GND

OUT1 ON

OUT2 ON

OUT3 ON

OUT4 ON
LDO ON

MAX1800

INPUT

0.7V TO 5.5V

3.3V

EIGHT OUTPUTS

1.8V

7.0V

15.0V

-7.5V

18.0V
12.0V

5.0V

LOGIC

CORE

CCFL MODULE

CCD BIAS

LCD BIAS

ZOOM
MOTOR DRIVE
(OPTIONAL)

N

P

DL

OSC

SLAVE

CONTROLLER

REF

MAX1801 SLAVE CONTROLLER

8-PIN SOT23

2.8mm x 2.9mm

32-PIN TQFP—5x5*

7mm x 7mm x 1mm

(DIMENSION INCLUDES LEADS)

MAX1800 STEP-UP MASTER

MAX1802 STEP-DOWN MASTER

MAX1801

V

IN

N

5.0V LENS COVER

DRIVE
(OPTIONAL)

DL

OSC

REF

ADD UP

TO FIVE SLAVE
CONTROLLERS

SLAVE

CONTROLLER

Smallest, Highest Efficiency
Multi-Output DC-DC Converter

Compact, Cost-Effective, Integrated Power Supply Solutions for
Digital Cameras and PDAs

Use the MAX1800 step-up master or the MAX1802 step-down master to provide all the voltage

outputs required in your digital camera and PDA designs from a single IC. They include high-effi-
ciency DC-DC converters with synchronous rectifiers to give over 90% efficient power conversion for
the logic supply, which uses >50% of the power in a camera system. They come in a small 32-pin
5mm x 5mm TQFP, which is 40% smaller than existing TQFP solutions. The MAX1800 and MAX1802
also eliminate external components such as power diodes, power switches, and at least one
transformer to save cost and size. For flexibility, add the low-cost, 8-pin SOT23 MAX1801 “slave”
controller to create optional features like a motor control supply for zooming and focusing. The
MAX1800/MAX1802 can provide all the voltages for logic, core, backlighting, LCD, and expansion
port of PDAs.

EXAMPLE OF A COMPLETE DIGITAL CAMERA POWER SUPPLY

(CAN ALSO BE USED IN PDAs)

MAX1800

MAX1802

Step-Up,
Step-Up/Down

Step-Down

0.7V to 5.5V Input

2.5V to 11V Input

One Li+,
Two or Three Alkaline

Two Li+,
Four Alkaline

Internal Step-Up,
Three Step-Up Controllers,
LDO Controller

Step-Down Controller,
Three Step-Up Controllers,
Internal Step-Down

1-, 2-, 3-, or 4-Cell Designs

*Dimensions include 5mm body plus 1mm for the length of each lead for a total of 7mm.

Lowest Cost Three- and Five-Output
xDSL and Cable Modem Power Supplies

High-Efficiency Step-Down Controller Plus Multiple LDO Controllers
on a Single IC

LDO4

POK

LDO2

LDO3

LDO1

DL

DH

N

N

GND

POWER OK
SIGNAL

V+

INPUT

LOW-COST

ADAPTER

4.5V TO 28V

3.3V
1A

FIVE OUTPUTS

2.5V
500mA

5V
100mA

12V
100mA

POSITIVE
LINE DRIVER

-12V
100mA

NEGATIVE
LINE DRIVER

I/O

CORE

AFE

MAX1865T

COMPLETE, LOW-COST, FIVE-OUTPUT xDSL MODEM SUPPLY

6

m

m

x 8.65

m

m

20

-PI

N QSO

P

6

m

m

x 4.9 m

m

16

-PI

N QSO

P

1864

1865

MAX1864

• Step-Down Controller

• Two Positive LDO Controllers

• 16-Pin QSOP Package

MAX1865

• Step-Down Controller

• Three Positive LDO Controllers

• One Negative LDO Controller

• 20-Pin QSOP Package

• No Current-Sense

Resistors Mean
Less Cost

• Step-Down Output:

1.25V to 5.5V

• LDO Outputs:

±1.25V to ±15V

• Power-OK Checks All

Outputs

• EV Kit Available to

Speed Designs

Use the MAX1864 and MAX1865 power-supply controller ICs to build the lowest cost xDSL and

cable modem consumer premises equipment (CPE) power supplies. They integrate a high-efficiency
step-down DC-DC controller and two to four linear regulator controllers that provide all the required
voltages for CPE. The current-mode step-down controller uses an external, dual N-channel MOSFET to
provide low-cost synchronous rectification for high efficiency and low heat. To further save cost, no
external current-sense resistor is required. Switching frequencies of 100kHz and 200kHz permit the
use of low-cost magnetics and aluminum electrolytic capacitors. The linear regulator controllers drive
inexpensive external bipolar junction transistors (B JTs).

110V Power Supply Controller
Integrates High-Voltage Startup FET

• Up to 300kHz Operation for Smaller

Magnetics and Capacitors

• Wide 11V to 110V Input Voltage Range

• Guaranteed ±2.5% V

REF

Accuracy

• Only 2.2mA Supply Current

• Input Feed-Forward

Compensation for Fast Line-
Transient Response

• Programmable: Current

Limit, Maximum Duty
Cycle, Oscillator
Frequency, Undervoltage
Lockout, and Soft-Start

• External Frequency Synchronization

• MAX5003 EV Kit Available to Speed

Designs

V

IN

V

IN

(UP TO 110V)

V

CC

R

SENSE

N_DRV

CS

V

OUT

5V

OPTOCOUPLER

FEEDBACK

MAX5003

HV PWM

CONTROLLER

ISOLATION

INTERNAL

110V STARTUP

TRANSISTOR

16

-PI

N QSO

P

4

.8

0m

m x 5.84

m

m

43% SMALLER FOOTPRINT

THAN COMPETITOR’S SO-14

Low-Cost, Dual-Output SLIC Supply
Uses Standard Transformer

EXT

GND

FREQ

N

SYNC

SYNC SIGNAL

(OPTIONAL)

FREQUENCY

SELECT

(100kHz TO 500kHz)

V

CC

INPUT

8V TO 24V

OUTPUT 1

-72V, 100mA RING BATTERY

OUTPUT 2

-24V, 400mA TALK BATTERY

OUTPUT VOLTAGE CAN BE SET

TO OPTIMIZE SHORT-LOOP OR

LONG-LOOP OPERATION WITH

VARIOUS SLIC ICs

FLYBACK TOPOLOGY REDUCES

INPUT RIPPLE CURRENT

STANDARD TRANSFORMER FROM

MULTIPLE VENDORS

REDUCES COST

LOW-COST

UNREGULATED

AC-DC

ADAPTER

DIGITAL

SOFT-START

MAX1856

EVALUATION KIT AVAILABLE TO SPEED DESIGNS. The MAX1856 can be configured to work with different input and
output voltages from those shown in this block diagram. For further information, please contact your local Maxim FAE or email us
at [e-mail].

Optimized for Telecom and

Data Communications Applications

MAX5910
MAX5917

BACKPLANE

(+10V TO +65V)

N.C.

PGOOD

FAULT

GND

V

OUT

ENABLE

UVLO

V

IN

DATA TERMINAL EQUIPMENT

• IP Phone

• Wireless LAN Access Node

(Eliminates AC Adapter)

• Security Camera

(Eliminates AC Adapter)

SAFELY CONNECT YOUR

DATA TERMINAL EQUIPMENT

TO A SWITCH/ROUTER

POWER SOURCE.

Part

MAX5910

MAX5917A

MAX5917B

Output Current Limit

(mA)

280

567

420

Pin-Package

8-SO

16-SO

16-SO

V

IN

UVLO

-16V to -65V

FAULT OUTPUT

ON/OFF

DGND

GATE

V

OUT

AGND

WITHSTANDS

-70V TRANSIENTS

MONITORS UVLO

POWER NOT GOOD,

LOAD DISCONNECT

& THERMAL SHUTDOWN

COMPATIBLE WITH

3.3V AND 5V LOGIC

ADJUST DEFAULT

UVLO THRESHOLD

WITH EXTERNAL

RESISTOR DIVIDER

CAN VARY

±5V

WITH RESPECT

TO AGND

♦ 2Ω INTERNAL POWER

SWITCH

♦ DELIVERS 13W POWER

(20W FOR MAX5912)

♦ DISCONNECTS LOAD AT

“ZERO CURRENT”

♦ SAFE HOT SWAP

MAX5911/

MAX5912

SIMPLE

SWAPPER™

Beats Competition 3 Ways

65V SWITCH IS IEEE802.3af COMPATIBLE

-48V SWITCH DELIVERS POWER AND DATA OVER

STANDARD CATEGORY 5 CABLE

Industry’s First Hot-Swap Switches
for Power-Over-LAN

Simple-Swappers™ Require No Design and No External Components

Simple-Swapper is a trademark of Maxim Integrated Products, Inc.

1) First IEEE802.3af-Compatible

Hot-Swap Switch

• Drives 500µF at Startup

• 500mA Output Current at

Startup

• Input Voltage Range:

+10V to +65V

2) Highest Integration

• Internal Switch Delivers 26W

of Power

• Built-In Undervoltage Lockout

(UVLO)

• Power Good Output Monitors:

UVLO, Power Not Good, and
Thermal Shutdown

3) Smallest Board Space and

Lowest Cost

• Requires No External

Components

• 60% Less Board Space than

Discrete Solutions

• 8-Pin or 16-Pin SO Packages

MAX5911

280

8-SO

MAX5912

415

16-SO

Highest Power Step-Up DC-DC
Delivers 20W to Replace Modules

Drop-In, Internal Switch 20W PWM Design in SO Package

ON

600kHz OR

SYNCHRONIZABLE

INPUT

0.7V to 5V

PROGRAMMABLE

CURRENT LIMIT

AND SOFT-START

OFF

OUTPUT

5V/4A

LOCAL

POWER BUS

1

µH

NETWORK OR TELECOM CARD

LOCAL ISOLATED

3.3V POWER BUS

MAX1709

MAX1708

16-PIN QSOP

5A MOSFET

16-PIN NSO

MAX1709

9A MOSFET

28-PIN QSOP

RACK-MOUNTED

TELECOMMUNICATIONS

SYSTEM

V

CC

INPUT

2.5V TO 5.5V

POWER INPUT

1V TO V

OUT

ON

OFF

FB

GND

EXT

SIMPLEST AND SMALLEST BOOST CONTROLLER CIRCUIT

ELIMINATES INRUSH CURRENT

OUTPUT

>V

IN

UP TO

30W

Built-in soft-start eliminates inrush current spikes, permitting use of a smaller and lower
cost input capacitor and inductor. The costly sense resistor is also eliminated.

V

CC

SHDN

N

2

.9

m

m x 2.8

m

m

6-

PIN

SOT2

3

400

µs/div

SOFT-START RESPONSE

V

IN

= 3V

V

OUT

= 12V

R

LOAD

= 200

Ω

I

LOAD

= 60mA

V

OUT

,

5V/div

I

L

, 1A/div

V

SHDN

, 5V/div

MAX1522
MAX1523
MAX1524

Simplest SOT23 Step-Up Controllers
Use Fewest Components

Use the MAX1522/MAX1523/MAX1524 DC-DC controllers to build the simplest and smallest

step-up circuits. These SOT23 controllers have an internal digital soft-start that eliminates the inrush
current spikes that shorten useful battery life. Soft-start also permits a smaller input capacitor. These
controllers eliminate the sense resistor to increase efficiency while saving space and cost. Finally, they
switch at up to 1MHz, permitting the use of a small inductor.

The MAX1708 and MAX1709 set a new standard of space savings for high-power step-up DC-DC

conversion. The MAX1709 packs a 22m

Ω, 9A, power MOSFET into a small SO package. It operates

from inputs in the 0.7V to 5V range, and provides up to 20W at fixed (3.3V or 5V) or adjustable (2.5V
to 5.5V) voltages. For lower power applications, choose the MAX1708, which provides up to 10W (5V at
2A) in a smaller 16-pin QSOP package. For added flexibility, both devices include programmable soft-
start and current limit, allowing external components to be optimized when less than full-power
capability is required.

1.5W

PACKAGE

OUTPUT
UP TO 5.5V
UP TO 500mA

1 x Li+

OR

2AA

INPUT

INPUT

INPUT

SMALLEST PACKAGE

ON

OFF

GND

ON

LX

OUT

OUTPUT
3.3V
UP TO 500mA

1 x Li+

2.5V TO

4.2V

STEP-UP/DOWN

ON

OR

OFF

GND

ON

LX

OUT

CORE POWER
3.3V OR 1.5V
UP TO 1.5A

DUAL OUTPUTS
SYSTEM POWER
5V OR 3.3V
UP TO 1.5A

1 x Li+

OR

2AA

HIGHEST POWER

ON

OFF

ON

DC/DC

LDO

OFF

GND

LX

INL

DC/DC OUT

FB

LDO DR

3

m

m

x

4.9mm x 1

.1

m

m

10

-PIN µMAX

4

.9

m

m

x 6mm x 1

.7

m

m

16

-PIN QSOP

5

m

m

x 6.3

m m x

1.

1m

m

16

-P

IN T

SSOP

-EP

1.5W

PACKAGE

OR

4

.9

m

m

x 6mm x 1

.7

m

m

16

-PIN QSOP

5

m

m

x 6.3

m m x

1.

1m

m

16

-P

IN T

SSOP

-EP

MAX1760

MAX1763

MAX1765

Highest Power, Low-Voltage, Boost
DC-DCs Are Now Smaller

50% Smaller Packages, 0.7V Startup Voltage, Up to 1.5A Output,
1MHz Switching (or Synchronize from 500kHz to 1.25MHz)

The MAX1760/MAX1763/MAX1765 are 50% smaller upgrades to the popular MAX1700 family of

low-voltage, high-power, high-efficiency PWM step-up DC-DC converters. The MAX1760 family
features smaller external components, adjustable current limit, and soft-start. They deliver more
power from low voltages than any other step-ups available: 1.5A from 3.6V

IN

(single Li+) and 400mA

from 1.2V

IN

(single NiMH or alkaline). Input range is 0.7V to 5.5V. Switcher output range is 2.5V to

5.5V. The MAX1763 and MAX1765 include a linear regulator for a second output.

EVALUATION KIT AVAILABLE TO SPEED DESIGNS. Conceptual schematics; not all components are shown.

Regulated Step-Up/Down Charge
Pump Delivers Guaranteed 125mA

OUT

IN

SHDN

GND

CXN

CXP

MAX1595-33
MAX1595-50

0,22

µF

1

µF

1

µF

4

m

m

x 4mm x

1m

m

12

-PIN QFN

5

m

m

x

3,1mm x

1,

1

m

m

8-

PIN µMAX

EINGANG

1,8V

BIS

5,5V

AUSGANG

5V ODER 3,3V

125mA

ON

OFF

ODER

1,48W

Verlustleistung

€1,69*

Preisgünstig mit

0,36W Verlustleistung

€1,60*

GEREGELTE AUFWÄRTS-/ABWÄRTS-

WANDLUNG MIT 1 KONDENSATOR

WÄHLEN SIE

LEISTUNG ODER

PREIS

INPUT VOLTAGE (V)

OUTPUT VOLTAGE (V)

0

1.0

2.0

3.0

4.0

5.0

6.0

0

1.0

2.0

3.0

4.0

5.0

6.0

V

OUT

= 5.0V, I

LOAD

= 125mA

V

OUT

= 3.3V, I

LOAD

= 75mA

NO INDUCTOR, ALL CERAMIC CAPACITORS

STEP-UP/DOWN REGULATION

†1000-up recommended resale. Price provided is for design guidance and is FOB USA. International prices will differ due to local duties, taxes, and exchange rates.

Delivers 5V or 3.3V from a 1.8V to 5.5V

Input with No Inductors

OPEN

D+

V

BUS

V

CC

RST

D+

D-

D-

GND

MAX5005
MAX5006
MAX5007

USB PORT

ENABLE

RESET

SELR

LDO

REGULATOR

1.5k

Ω

5V

3.3V

1

µF

CERAMIC

SUPERVISORY

INTERNAL D+ AND D- TERMINATION
RESISTOR AND CONTROL

♦ USE SELR PIN TO CONFIGURE USB

PERIPHERAL FOR FULL SPEED OR
LOW SPEED

♦ USE ENABLE PIN TO DESELECT INTERNAL

TERMINATION RESISTOR

µP RESET CIRCUIT

♦ ENABLES USB CONTROLLER

WHEN V

OUT

IS IN

REGULATION

♦ 200ms TIMEOUT PERIOD

LOW QUIESCENT CURRENT LDO REGULATOR

♦ 3.3V/150mA OUTPUT
♦ 30µA SUPPLY CURRENT INDEPENDENT OF LOAD
♦ STABLE WITH 1µF CERAMIC OUTPUT CAPACITOR

ROBUST TRANSIENT VOLTAGE
SUPPRESSORS FOR DATA LINES

♦ IEC 1000-4-2 AIR DISCHARGE

VOLTAGE TO

±15kV

♦ IEC 1000-4-2 CONTACT DISCHARGE

VOLTAGE TO

±8kV

♦ 6A SURGE CURRENT RATING

3.3V USB

CONTROLLER

New! Schematics and Bills of
Materials Online

Choose Proven, Lab-Tested Circuits from Maxim’s Growing Library of
Applications

Maxim has placed over 30 useful power-supply application circuits on our website for you to

browse and download. You can sort the list by topology, input voltage, or output voltage and download
schematics and component bills of materials, including part numbers and vendor names. You can also
submit an application for an evaluation board to be built for you. Check the list often for new
additions. Visit http://dbserv.maxim-ic.com/PowerSupplies.cfm

Topology

Step-Down

Step-Up

Inverter

Input Voltage

(V)

5

2.5

3.3

Output Voltage

(V)

1.2

5

-5.2

Key Attributes

Tracking supply for DDR termination

Internal switch, smallest size, synchronization

<3mm profile, very low ripple

Schematic and

Bill of Materials

Download

Download

Download

Evaluation

Board

Request

Request

Request

Multi-Output

12

3.3, 2.5, 1.8, -4.8

Low-cost, single controller design

Download

Request

Output Current

(A)

6

3

0.3

1, 0.3, 0.2, 0.06

Request
Evaluation
Board

Download
Schematic and
Bill of Materials

Sort By
Output
Current

Sort By
Input
Voltage

USB Power Management IC
Integrates ±15kV Transient
Voltage Suppressors

Highest Integration Saves Board Space, Cost, and Design Time, Fits
in a 10-Pin µMAX Package

Push-Pull Active High

MAX5007

Push-Pull Active Low

MAX5006

Open Drain

MAX5005

Reset Output

Part

t = 10ms/div

SHORT-CIRCUIT

FAULT RESPONSE

5V, V

IN

5V

0

5V

0

1A

0

V

OUT

FAULT
INDICATOR

I

OUT

1

SHORT APPLIED

2

FAULT INDICATOR
TRIPS AFTER 20ms BLANKING
TO PREVENT HOT-SWAP GLITCHES

3

FAULT-CONDITION
CURRENT LIMITED TO 350mA

RMS

BY PULSING (COMPETITOR'S
CURRENT SHOOTS TO I

SHORT

)

4

SWITCH TURNS ITSELF OFF
AFTER 20ms (COMPETITION WAITS
FOR MICROPROCESSOR SIGNAL,
WASTING POWER & RISKING DAMAGE)

5

SHORT-CIRCUIT REMOVED AND
AUTOMATICALLY DETECTED BY MAX1823
(COMPETITION REQUIRES DETECTION
CIRCUIT & MANUAL POWER RECYCLING)

6

20ms RESET SIGNAL ALLOWS
PROPER SYSTEM START-UP

7

SWITCH TURNS ITSELF ON 20ms
AFTER DETECTING FAULT REMOVAL
(COMPETITION REQUIRES MICRO-
PROCESSOR SIGNAL)

MAX1823

Smart Dual USB Switch Reduces
Software Overhead with
Auto Turn-Off/-On

World’s Smallest, Dual, Current-
Limited Switch with Fault-Blanking

The MAX1812 is the world’s smallest, dual, current-limited switch for USB applications. Each

channel is guaranteed to supply 500mA and meets all USB specifications. Internal fault-blanking
prevents momentary faults (capacitive loads) from resetting the host system and eliminates the need
for external components.

INTERNAL FAULT-BLANKING SAVES COMPONENTS AND PREVENTS HOT-SWAP GLITCHES

500mA

SWITCH

INA

5V

5V

OUTA

FAULTA

20ms

DELAY

20ms

DELAY

FAULTB

OUTB

TO USB
PORT A

TO USB
PORT B

INB

500mA

SWITCH

HOST

µP

INTERNAL

BLANKING

ELIMINATES FOUR

EXTERNAL

COMPONENTS

MAX1812

3

m

m

x

4.9mm x 1

.1

m

m

10

-PIN µMAX

AREA = 2.95mm x 4.9mm

HEIGHT = 1.11mm, MAX

OUTPUT

3.3V/5V

UP TO 4A

22

µH

220

µF

40m

Ω

0.1

µF

4.7

µF

4.7

µF

47

µF

VL

REF

CS

EXT

OUT

V+

VH

MAX1744

INPUT

4.5V TO 36V

SHDN

OFF

ON

GND

36V Input, 20W Output Step-Downs

Save Space

NEW

100

0

0.0001

0.001

0.01

0.1

1

10

EFFICIENCY vs. LOAD CURRENT

(V

OUT

= 5.0V)

20

LOAD CURRENT (A)

EFFICIENCY (%)

40

60

80

A: V

IN

= 7.2V

B: V

IN

= 12.0V

C: V

IN

= 24.0V

D: V

IN

= 36.0V

B

A

D

C

• High-Voltage Operation

(Up to 36V

IN

)

• 10-Pin µMAX Package

• Up to 330kHz Switching

Frequency Reduces
Component Sizes

• Output Power >20W

• High Efficiency

• 90µA Quiescent Supply

Current

• 4µA Shutdown Current

• Output Voltage: 3.3V/5V

(MAX1744) Adj. 1.25V to
18V (MAX1745)

DIRECT STEP-DOWN FROM 24V WITHOUT 2-STAGE EFFICIENCY LOSS

AUDIO

RTC

WLAN

VIDEO

I/O

P

INTERNAL

24V P-CHANNEL

MOSFET

DIRECT CONVERSION

FROM 4.5V TO 24V

(FOUR Li+ OR AC-DC

ADAPTER)

I

Q

= 12

µA

MAX1776

I

Q

= 15

µA

500mA

8-PIN

µMAX

OUTPUT

1.25V TO V

IN

UP TO 500mA

90% EFFICIENCY

MAX1836/MAX1837

125mA/250mA

6-PIN SOT23

MAX1836

Smallest Step-Down Converter with
24V Internal MOSFET Switch

3-/4-Cell Li+ Powered, Low I

Q

, Keep Alive, and Wake-On LAN Supply

The MAX1837 delivers up to 250mA, the MAX1836 delivers up to 125mA, and the MAX1776

delivers up to 500mA, permitting optimal inductor selection. The MAX1836/MAX1837 come in a 6-pin
SOT23 package, and the MAX1776 comes in an 8-pin µMAX package. Both convert directly from 24V
inputs, eliminating the intermediate step-down voltage that wastes over 15% of the battery life and
increases complexity. Applications include I/O, audio, keep-alive, WLAN, and video supplies in
notebook and hand-held systems powered by up to four lithium batteries and AC-DC adapters.

3

m

m x 5m

m

10

-PI

N

µM

AX

Direct conversion from 24V to 3.3V saves 15% power by eliminating compound efficiency losses generated when converting
from 24V to 5V and then from 5V to 3.3V.

Smallest 250mA Step-Downs Achieve
95% Efficiency for Sub-2V Logic

1MHz, 600mA Step-Down Powers DSP
Cores Using Inexpensive Capacitors

The MAX1821 is the first 1MHz PWM converter capable of delivering precision line and load regu-

lation for the latest DSP cores using low-ESR ceramic input and output capacitors. The precision line
and load regulation is achieved through an innovative current-mode control algorithm. Its unique
slope compensation and high-bandwidth error amplifier, combined with a simple external compensa-
tion circuit, stabilize the converter with only a small 4.7µF ceramic capacitor. The MAX1821
can operate in PWM or PFM mode to maximize standby and operational efficiencies. To maximize
battery life, the MAX1821 delivers > 93% efficiency using an integrated low R

DSON

switch and synchro-

nous rectifier.

LX

BATT

FB

COMP

SHDN

SKIP

PWM

PFM

MAX1821

4.7

µH

4.7

µF

GND

INPUT

2.5V to 5.5V

OUTPUT 1.8V AT 600mA

ADJUSTS DOWN TO 1.25V

ON

OFF

REF

4.7

µF

• 600mA Guaranteed Output

Current

• 1MHz PWM Switching Frequency

• Requires only 4.7µF Ceramic

Capacitor

• Excellent Line and Load Regulation

• Synchronize to 2.5G (19.8MHz)

or 3G (13MHz) System Clock

• Programmable Output Voltage

from 1.25V to 5.5V

• No Schottky Diode Required

High-Speed Converter Provides Excellent Line and Load Regulation
Using Tiny, 4.7µF Ceramic Capacitors Instead of Expensive, High-
ESR Tantalum Capacitors

The MAX1733/MAX1734 step-down DC-

DC converters deliver over 250mA to outputs
as low as 1.25V and have 1.5% output voltage
accuracy. The input voltage range of 2.7V to
5.5V makes these devices ideal for portable
applications powered from a single lithium cell,
from three alkaline or NiCd/NiMH cells, or
from a regulated 3.3V or 5V supply.

These converters use a unique proprietary

current-limited control scheme that maintains
a low 40µA quiescent supply current, while
their high 1.2MHz (max) switching frequency
and internal synchronous rectification significantly improve efficiency and minimize solution size. This
reduces external component size and eliminates the external Schottky diode required with conven-
tional step-down converters. Only three small external components are needed for a complete DC-DC
solution.

The MAX1733 provides a resistor-adjustable output voltage, while the MAX1734 is available in a

variety of preset output voltages. Both devices are available in space-saving 5-pin SOT23 packages.

OUTPUT

1.25V TO 2.5V (MAX1733)

1.5V OR 1.8V (MAX1734)

UP TO 250mA

10

µH

SHDN

IN

GND

OUT

LX

MAX1734

INPUT

2.7V TO 5.5V

OFF

ON

5-

PIN

SOT2

3

3

m

m x 3m

m

4.7

µH

RF RECEIVE SECTION

V

OUT

CONTROL

DAC

13MHz OR 18MHz

SYSTEM CLOCK

BASEBAND

PROCESSOR

4.7

µF

LX

OUT

REF

GND

SYNC

MAX1820

BATT

RF TRANSMIT SECTION

2.5G AND 3G

FIXED-GAIN

LINEAR PA

OUTPUT OF HIGH-SPEED DC-DC

TRACKS PA POWER ENVELOPE WITHIN 30

µs

1000

100

10

-10

-5

0

5

10

TRANSMIT POWER (dBm)

15

20

25

BA

TTER

Y CURRENT (mA)

SAVE 83% BATTERY CURRENT

PA CONNECTED

TO MAX1820

PA CONNECTED TO BATTERY

REDUCE BATTERY CURRENT

FROM 62mA TO 11mA

DATA MODE

400

µs/div

PA SUPPLY
VOLTAGE

FAST 30

µs

SETTLING TIME

VOICE MODE

DYNAMIC OUTPUT

0.4V TO 3.4V IN 30

µs

UP TO 600mA

INPUT

2.7V TO 4.2V

CLOCK SYNC

REDUCES NOISE

MAX1820Z
MAX1820Y*
MAX1820X*

NO SYNC
÷ 18 PLL

÷ 13 PLL

ONLY SUPPLY WITH

DAC INPUT FOR DIRECT

COMMUNICATION

FROM BB PROCESSOR

Li+ BATTERY

500mV/div

Reduce WCDMA PA Current Draw
83% with Dynamically Controlled
Step-Down DC-DC

High-Speed DC-DC Adjusts 2.5G and 3G PA Supplies to Match
Transmit Power

The MAX1820 is the first step-down

converter designed specifically for PAs in 2.5G
and 3G cellular phones. The baseband
processor dynamically programs the converter
output voltage based on the variable power
required by the PA. The high-speed MAX1820
converter varies its output voltage from 0.4V to
3.4V in less than 30µs, tracking the PA transmit
power envelope. By matching the PA supply
voltage envelope, the PA minimizes power loss
and maximizes battery life. The MAX1820 is
equipped with a divide-by-13 or
divide-by-18 phase-locked-loop (PLL) to
synchronize to a 2.5G or 3G system clock. An
actual test with a WCDMA PA proved this
synchronization method does not add spurious
noise into the RF band.

*Future product—contact factory for availability.

ON

INDEPENDENT

CONTROLS

EN1

OUT1

2.2

µF

4.7

µF

IN1

OFF

IN2

IN3

2.2

µF

2.2

µF

OUT3

OUT2

EN3

EN2

BP

GND

0.01

µF

Li+

BATTERY

INPUT

2.5V TO 5.5V

3 OUTPUTS

1.8V TO 3.3V

100mA

1.8V TO 3.3V

100mA

1.8V TO 3.3V

100mA

MAX8890

CERAMIC INPUT AND

OUTPUT CAPACITORS

SAVE COST

FACTORY PRESET

OUTPUTS SAVE

SPACE

100

1000

0

10

20

30

40

60

50

80

70

0.1

1

10

67dB POWER-SUPPLY

REJECTION RATIO

FREQUENCY (kHz)

PSRR (dB)

C

IN

= 1

µF + 0.1µF

I

OUT

= 10mA

100

1000

0

100

10

1000

0.1

1

10

LOW-CROSSTALK VOLTAGE

FREQUENCY (kHz)

CROSSTALK (

µ

Vp-p)

LOW-IMPEDANCE INPUT
I

OUT1

= 100mA SINUSOIDAL LOAD

I

OUT3

= 10mA

4

m

m

x

4 m m x 0

.8

5

m

m

12

-PIN QFN

Triple, Low-Noise, Low-Dropout
Linear Regulators Provide Complete
RF Power

67dB PSRR, Low-Crosstalk Voltage, and 45µV

RMS

Noise Provide

Flawless Transmission

The MAX8890 contains three identical 100mA, low-noise linear regulators in a low-profile 4mm x

4mm x 0.85mm QFN package. Their 67dB PSRR, low-crosstalk voltage, and 45µV

RMS

noise make

them ideal for the noise-sensitive RF sections of cellular phones and wireless PDAs. Low 50mV
dropout at 100mA load maximizes battery life. Output voltages are preset from 1.8V to 3.3V in 50mV
increments. The MAX8890 is priced at $0.99

†

.

3 LOW-NOISE LDOs IN A SINGLE QFN PACKAGE

†1000-up recommended resale. Price provided is for design guidance and is FOB USA. International prices will differ due to local duties, taxes, and exchange rates.

OFF

ON

SHDNB

UP TO 160mA

1.8V TO 3.3V

UP TO 160mA

1.8V TO 3.3V

DUAL

OUTPUTS

IN

GND

OUTA

OUTB

MAX8883

INPUT

2.5V TO 5.5V

OFF

ON

SHDNA

INCREDIBLE 1.0

Ω

MOSFET PASS SWITCHES

UP TO 160mA

FROM EACH OUTPUT

80

0

0.01

0.1

1

10

100

1000

PSRR VS. FREQUENCY

10

20

FREQUENCY (kHz)

PSRR (dB)

40

30

60

70

50

>75dB

at up to 10kHz!

>65dB

at up to 100kHz!

100

0

CHANNEL-TO-CHANNEL

ISOLATION VS. FREQUENCY

20

FREQUENCY (kHz)

CHANNEL-TO-CHANNEL ISOLATION (dB)

40

60

80

10

30

50

70

90

0.01

0.1

1

10

100

1000

>90dB

at up to 10kHz

>85dB

at up to 100kHz

>65dB

at up to 1MHz

50% SPACE SAVINGS AND EXCELLENT AC PERFORMANCE

6-

PIN

SOT2

3

2

.8

m

m x 2.9

m

m

0.7W

DISS

IPAT

ION

G

RE

AT

ISOLA

TION

GREAT PS

RR

DUAL LDOs IN

TINY SOT23 PACKAGE

First Dual 160mA LDOs in SOT23

These dual linear regulators offer better AC performance
and lower dropout voltages than single devices requiring twice the board space.

The MAX8882/MAX8883 are

dual, low-noise, low-dropout
linear regulators that operate
from a 2.5V to 6.5V input and
deliver up to 160mA of continu-
ous output current from each
output. These devices are less
than half the size of their closest
competition, yet their ultra-
low 1.0

Ω on-resistance is lower

than most single-LDO competi-
tion in the same package. Each
LDO has only 72mV dropout at
80mA for longest battery life.
Both devices are available in fixed
output voltages of 2.85V/2.85V,
3.3V/2.5V, 3.3V/1.8V, 3V/3V
and 2.5V/1.8V.

First 500mA Linear Regulator with
0.8V Output in 1.3W µMAX Package

The MAX1806 delivers outputs down to 0.8V at 500mA for new and future processor core power

supplies. The small µMAX package is specially constructed to dissipate 1.3W, which is 3.6 times more
than the competitor’s parts in the same package. Output voltage tolerance is ±1% and is preset (to
save space and cost) or adjustable from 0.8V to 4.5V (for flexibility). A Power-OK output signal
indicates when the output voltage drops from its nominal value by more than 7%. It includes current
limiting and shuts off in the event of short-circuit or thermal-overload faults. The MAX1806 uses a
P-channel MOSFET power switch so there is no large base current draw, even in dropout.

• Guaranteed 500mA Output

• Regulated Outputs Down to 0.8V

• ±1% Voltage Accuracy:

Preset Voltages: 0.8V, 1.5V,
1.8V, 2.5V, or 3.3V
Adjustable Range: 0.8V to 4.5V

• Power-OK Output

• 1.3W, 1.1mm-High 8-Pin µMAX

Package

• 2.25V to 5.5V Input Range

• Low 175mV Dropout at 500mA

• 210µA Quiescent Supply Current

• 0.02µA Shutdown Current

OPERATING RANGE, V

OUT

= 0.8V

600

500

400

300

OUTPUT CURRENT (mA)

200

100

0

2.0

2.5

3.0

3.5

4.0

INPUT VOLTAGE (V)

4.5

5.0

5.5

6.0

COMPETITOR’S

RANGE

MAX1806

1.3W

µMAX

RANGE

World’s Smallest 0.5A and 1A
Linear Regulators

Special High-Power Packages Dissipate 1.3W and 1.5W

MAX1792

MAX1793

8-PIN SO

AREA = 31mm

2

y = 5.1mm

x = 6.2mm

SOT223

AREA = 50.3mm

2

y = 7.5mm

x = 6.7mm

8-PIN

µMAX

AREA = 15mm

2

y = 3.1mm

x = 5.0mm

1.1mm

HIGH

16-PIN TSSOP

AREA = 33.2mm

2

y = 5.1mm

x = 6.5mm

ONLY 1.1mm

HIGH

51%

SMA

LLER

34%

SMA

LLER

0.5A, LOW-DROPOUT

LINEAR REGULATOR IN 1.3W

µMAX

1A, LOW-DROPOUT

LINEAR REGULATOR IN 1.5W TSSOP

• ±1% Output Voltage Accuracy

• Fixed Outputs (1.5V, 1.8V, 2.5V,

3.3V, 5.0V) or Adjustable from
2V to 5V

• Low 130mV Dropout at 0.5A (MAX1792)

• Low 210mV Dropout at 1.0A (MAX1793)

• Thermal Overload Protection

Lowest Dropout and Lowest Cost
SOT23 and QFN LDOs for Baseband
and RF Chipsets

SMBus serial interface, Level 2 Duracell/
Intel-compliant charger

SBS Level 2 (1.0 compliant) smart battery charger,
SMBus interface, current-limiting input

High-efficiency switch-mode controller

Features

Yes

Yes

Yes

EV
Kit

SMBus

controlled

—

Voltage and

current limit

Charge

Termination

Method

Fast, up to 4A

Independent

—

MAX1647

Fast

Independent

1 to 4

MAX1645A

Fast

Li+

1 to 4

MAX745

Charge

Rate

Cell

Chemistry

No. of Series

Li+ Cells

Part

16-NSO,

20-SSOP

20-SSOP

Pin-Package

28-SSOP

14V

IN

internal switches, sync rectified step-down,

input-current-limit loop, timers

28V

IN

external switches, sync rectified step-down

controller, input-current-limit loop, timers

SMBus serial interface, Level 2 Duracell/
Intel-compliant charger

Yes

Yes

Yes

Voltage and

current limit

Voltage and

current limit

SMBus

controlled

Fast, up to 1.5A

Li+

1 to 3

MAX1757

Fast, up to 4A

Li+

1 to 4

MAX1737

Fast, up to 4A

Independent

4

MAX1667

28-SSOP

20-SSOP

28-SSOP

Pulse charger, ext switch, no heat
dissipation, upgrade to MAX1679

Linear charger, internal switch,
power through USB port, 0.5% precision

28V

IN

internal switches, sync rectified step-down,

input-current-limit loop, timers

—

—

Yes

Voltage and

current limit

Voltage and

current limit

Voltage and

current limit

Fast, up to

800mA

Li+

1

MAX1879

Fast, up to

500mA

Li+

1

MAX1811

Fast, up to 1.5A

Li+

1 to 4

MAX1758

8-µMAX

28-SSOP

8-SO (1.4W)

15V

IN

, ext switch pulse charger

integrated with fuel gauge

28V

IN

ext switches, sync rectified

step-down controller, input-current-limit loops

28V

IN

lowest cost step-down controller,

300kHz PWM, input-current-limit loop

DS2770K*

Yes

Yes

I

MIN

, timer

Voltage and

current limit

Voltage and

current limit

Fast

Li+/Ni

1

DS2770*

Fast, up to 4A

Independent

2 to 4

MAX1772

Fast, up to 4A

Li+/Ni

2/3/4

MAX1873R/S/T

16-TSSOP

16-QSOP

28-QSOP

*Future product—contact factory for availability.

Battery Chargers Selector Table

120mA output, reverse-battery protection

120mV dropout at 500mA

20mA output, 2µA quiescent current,
reverse-battery protection

Features

MAX8863/4

MAX1725/6

Part

MAX1818

150mA output, thin 1.1mm (max) height, reverse-battery
protection

150mA output with POK, reverse-battery protection

150mA output, reverse-battery protection

MAX8877/8

MAX8867/8

MAX8875

150mV dropout at 300mA, thin 1.1mm (max) height

Dual 160mA output LDOs in SOT23

200mA output, reverse-battery protection

MAX8887/8

MAX8880/1

MAX8882/3

Triple 100mA output LDOs in 4mm x 4mm QFN

MAX8890

2.8, 2.84, 3.15, or Adj 1.25 to 6.5

1.5, 1.8, 2.0, 2.5, 3.3, 5, or Adj 1.25 to 5

1.8, 2.5, 3.3, 5, or Adj 1.5 to 5

Output Voltages (V)

1

1

Output

Capacitance (µF)

3.3

Fixed 2.5 to 5 in 100mV increments

Fixed 2.5 to 5 in 100mV increments

Fixed 2.5 to 5 in 100mV increments

1

1

1

Fixed 1.5 to 3.3 in 100mV increments

Fixed 1.8 to 3.3 in 100mV increments

1.8, 2.5, 3.3, 5, or Adj 1.25 to 5

2.2

1

2.2

Fixed 1.8 to 3.3 in 50mV increments

2.2

CUSTOMIZED

OUTPUT

VOLTAGES

BATT

GND

THERM

P-Ch

GATE

0.75% VOLTAGE

ACCURACY

CHG

OPTIONAL

LED

INPUT

CURRENT-LIMITED

WALL-CUBE

5V TO 22V

800mA

TEMPERATURE

PROTECTION

(OPTIONAL)

IN

MAX1879

SINGLE Li+

BATTERY

ONLY ONE EXTERNAL FET

REQUIRED FOR COMPLETE

Li+ CHARGER

PULSE CHARGING DECREASES SYSTEM

HEAT AND INCREASES RELIABILITY

Li+

Cool Li+ Battery Charger Has
Virtually No Power Dissipation

Safe, Simple, and Inexpensive Pulse Charger Dissipates No Heat

Safety Features Include:

• Continuous Over/Undervoltage

Protection

• ±0.75% Charge Voltage Tolerance

• 6.25-Hour Charging Time-Out

Prevents Infinite Trickle-Charge

• Safely Precharges Near-Dead Cell

• Over/Undertemperature Protection

• Automatic Charging Restart at 4V

• Safe, Simple, and Inexpensive Pulse

Charger Dissipates No Heat

• Evaluation Kit Available to

Speed Designs

Single-Cell Li+ Protector Enables

Power Control Function in
Battery Pack

The DS2720* single-cell Li+ protection IC integrates memory, overtemperature protection, and the

ability to communicate with the host processor, along with the standard over/undervoltage and over-
charge protection found in popular standalone protectors. Because the host can communicate with the
DS2720, it can control the protection MOSFETs in software, enabling power control through the
DS2720 and MOSFET.

• Li+ Safety Circuit;

• Overvoltage Protection
• Overcurrent/Short-Circuit

Protection

• Undervoltage Protection
• Overtemperature Protection

• Controls High-Side N-Channel

Power MOSFETs

• System Power Management and

Control Feature Support

• 8 Bytes of Lockable EEPROM

• 1-Wire

®

, Multinode Digital

Communication Interface

• 8-Pin µSOP Package

+

-

PLS

CP

PS

DC

DQ

CC

V

SS

V

DD

DATA

PACK -

PACK +

POWER
SWITCH

HOST

DS2720

*Future product—contact factory for availability.
1-Wire is a registered trademark of Dallas Semiconductor.

FUTU

RE

PRO

DUC

T

PROTECTOR

(Lithium only)

64-BIT

ROM

TIME

TEMP

ADC

E

2

BATTERY PACK

V-

DATA

V+

HANDSET

BASEBAND

PROCESSOR/

ASIC

4.7k

Ω

Electronically Label Battery Packs
with Low-Cost, 1-Wire Digital
Interface ICs

• 1-Wire Digital Interface

• Unique 64-Bit Serial Number

• Reduces Battery Contacts

Reduced to Three, Regardless
of Device Chosen

• User-Programmable EEPROM:

16 Bits (DS1822), 256 Bits
(DS2436) 1024 Bits (DS2432)

• Real-Time Clock (DS2415)

• Local Temperature Sensor:

9 Bit to 12 Bit (DS1822),
13 Bit (DS2436)

• Battery-Voltage ADC:

10 Bit (DS2436)

• 512-Bit SHA-1 Encryption

Engine (DS2432)

Dallas Semiconductor silicon label ICs tag a unique and unchangeable electronic label to the battery

pack. Each offers an array of feature functions to fit different cellular phone applications. The low-cost
DS2401 is the base model of this series, containing a 64-bit ROM accessible from the 1-Wire serial digital
interface. The DS2415 adds a real-time clock to the serial number, eliminating the need to have a back-
up battery for the real-time clock in the host product. The DS1822 replaces thermistors in the battery
pack by integrating a local digital thermometer and 16 bits of EEPROM to the 64-bit ROM. The DS2432
features 1024 bits of user EEPROM and a 512-bit SHA-1 algorithm that encrypts the EEPROM array.
The security offered in the DS2432 deters non-OEM battery packs, thus enhancing accessory revenue
and more importantly, increasing the safety to the user of the product with lithium-based packs. The
DS2436 provides data storage in the form of the 64-bit ROM and 256-bit user EEPROM, and replaces the
pack thermistor and ADCs in the host reserved for measuring pack voltage.

Battery Pack ID Solutions Selector Table

TO-92, 8-SO,
Flip Chip (2.0 x 1.4)

6-TSOC,
Flip Chip (1.4 x 1.1)

Pin-Package

(mm

2

)

TO-92, 6-TSOC,
CSP (1.4 x 0.7)

6-TSOC,
Flip Chip (2.5 x 1.8)

DS1822

—

Part

64-Bit

ROM

Real-Time

Clock

1-Wire

Interface

DS2401

—

DS2415

DS2432

—

TO-92, 8-SO

DS2436

—

8-SO

DS2438

16-TSSOP,
Flip Chip (3.2 x 2.7)

DS2760

—

16-TSSOP

DS2770*

—

2

EEPROM

(Bytes)

—

—

1024 bits

32

40

32

32

12

Local Temp

Sensor (Bits)

—

—

—

13

13

11

11

—

Voltage

ADC (Bits)

—

—

—

10

10

11

11

—

Fuel

Gauge

—

—

—

—

—

Li+

Protector

—

—

—

—

—

Single

cell

—

DS1701K

EV Kit

—

—

—

DS2436K

DS2438K

DS2760K

DS2770K*

NEW

FUTU

RE

*Future product—contact factory for availability.

8-µSOP

DS2720*

—

8

—

—

—

Single

cell

DS2720K*

FUTU

RE

EN

SET

Li+

BATTERY

2.5V, 5.5V

OFF

ON

VCNTL

LED1

LED2

LED3

GND

SIMPLE

BRIGHTNESS

CONTROL

THIN SOT23

1mm HEIGHT

BETTER THAN

0.3% LED-TO-LED

MATCHING

5

10

15

20

25

30

3.0

3.2

3.4

3.6

3.8

4.0

4.2

BATTERY VOLTAGE (V)

LED CURRENT (mA)

350mV

3 RANDOM LEDs
USING MAX1916

SAME 3 LEDs USING

34.8

Ω BALLAST RESISTORS

POOR CURRENT

MATCHING

MAX1916

200mV

DROPOUT EXTENDS

BATTERY LIFE

BETTER MATCHING, LONGER BATTERY LIFE

+

ADDS 350mV

TO BATTERY LIFE

GOOD CURRENT

MATCHING

Power 3 White LEDs from Single Li+
with 0.3% Brightness Matching

Lowest Dropout (200mV) Current Regulator Fits in 1mm-Thin SOT23

The MAX1916 triple-output current regulator provides significantly better matching than tradi-

tional ballast resistor schemes and provides longer battery life. Ballast resistors only provide 2:1 LED
matching. The MAX1916 regulates three LED currents with 0.3% matching, eliminating costly factory
calibration and the need to purchase LEDs with matched forward voltages (VF). 200mV dropout allows
LEDs to be powered directly from a single-cell lithium-ion (Li+) battery for a longer time, extending
battery life.

The MAX1916 eliminates costly factory calibration and special batch ordering while improving battery life and brightness matching.

TRIPLE WHITE LED SUPPLY IS SUPERIOR TO BALLAST RESISTORS

High-Efficiency SOT23 Step-Up
Current Source Powers Up to 6 White
LEDs with Uniform Brightness

The MAX1848 is the

first high-efficiency step-up
DC-DC converter that
regulates current instead of
voltage to power white LEDs
for backlights in cell phones
and PDAs. It powers two or
three white LEDs in series
(up to 6 total), instead of in
parallel, to eliminate bright-
ness mismatch caused by
different threshold voltages.
An internal N-channel
MOSFET switch provides
85% efficiency, 40% better
than traditional doubling
charge-pump solutions.

MAX1848

V+

3.3

µF

33

µH

1

µF

CNTL

COMP

OUT

GND

CS

LX

LOGIC OR

DAC

OUTPUT

UP TO 13V

UP TO 60mA

INPUT

2.6V TO 5.5V

RSENSE

5

Ω

20

Ω

SERIES LEDs HAVE MATCHED LED

CURRENT AND UNIFORM BRIGHTNESS

NO CALIBRATION:

5% CURRENT TOLERANCE WITH

STANDARD LOW-COST

CHIP RESISTOR

PROGRAMMABLE

BRIGHTNESS

MATCHED CURRENT

=

UNIFORM BRIGHTNESS

2

.8

m

m x 2.9

m

m

8-

PIN

SOT2

3

0.15

µF

3.0

4.0

4.5

INPUT VOLTAGE (V)

90

85

80

75

70

65

60

55

50

45

40

35

30

EFFICIENCY (%)

3.5

40% MORE EFFICIENT,

1.8x LONGER BATTERY LIFE

I

OUT

= 15mA

1.8x

LONGER

BATTERY

LIFE

DOUBLING CHARGE

PUMP WITH THREE

LEDs IN PARALLEL

LOWER INPUT RIPPLE

THAN CHARGE PUMP

NEW

MAX1848

WITH THREE LEDs

IN SERIES

25

Ω

NO BALLAST RESISTORS AND

NO FACTORY CALIBRATION

Most Efficient 1.4MHz SOT23
Current-Mode Step-Up DC-DC
Converter

0.7

Ω On-Resistance and 200µA I

Q

—Highest Efficiency

MAX1896

SS

INPUT

2.6V to 5.5V

GND

R2

R1

100

90

80

EFFICIENCY (%)

70

60

50

0

100

200

OUTPUT CURRENT (mA)

BETTER EFFICIENCY

300

400

ON

OPTIONAL

SOFT-START

OFF

FB

LX

1

3

2

4

6

5

SHDN

IN

OUTPUT

UP TO 13V,

UP TO 600mA

MAX1896

V

IN

= 3.3V

V

OUT

= 5V

COMPETITION

The MAX1896 is pin compatible with the LT1613 and has higher efficiency due to lower switch on-resistance and lower quiescent
supply current.

3

.0

m

m x 3.0

m

m

6-

PIN

SOT2

3

MOST EFFICIENT & SMALLEST SOT23 13V STEP-UP CONVERTER

The MAX1896 uses current-mode control and 1.4MHz fixed-frequency pulse-width modulation

(PWM) to provide over 90% efficiency, fast transient response, and operation with physically smaller
components. It features 200µA quiescent supply current, low R

ON

(on-resistance), 0.01µA logic-

controlled shutdown current, and programmable soft-start. The MAX1896 is intended for PDAs, LCD
panels, and hand-held equipment.

Battery and load

disconnect

Battery connects

to load

Battery connects

to load

IN SHUTDOWN

MAX1834

OUTPUT

Adjustable (2V to 5.5V)

Fixed 3.3V

Adjustable (2V to 5.5V)

MAX1833

MAX1832

PART

NUMBER

Battery and load

disconnect

MAX1835

Fixed 3.3V

World’s First Step-Up Converters
with “Reverse-Battery” Protection

SOT23 Boost Converters Use Only 4µA and Integrate Protection to
Save Cost

MAX1832
MAX1833
MAX1834
MAX1835

GND

P

N

INTERNAL SWITCH

OPENS IF BATTERY

IS REVERSED

PROTECTION INTEGRATED; SYNCHRONOUS RECTIFIER INTEGRATED

OUTPUT

2V TO 5.5V

UP TO 150mA

TINY

6-PIN SOT23

SAVES SPACE

INPUT

RANGE

1.5V TO 5.5V

BATTERY

ACCIDENTLY

REVERSED

-

+

SHDN

OFF

ON

NO REVERSE CURRENT
(IN-FAULT CONDITION)

FAULT

CONDITION