TM
MP2360
1.8A, 24V, 1.4MHz
Step-Down Converter
TM
The Future of Analog IC Technology
DESCRIPTION
FEATURES
The MP2360 is a monolithic step-down switch
" 2.5A Peak Output Current
mode converter with a built-in internal power
" 1.8A Continuous Output Current
MOSFET. It achieves 1.8A continuous output
" 0.3&! Internal Power MOSFET Switch
current over a wide input supply range with
" Stable with Low ESR Output Ceramic
excellent load and line regulation. Current mode
Capacitors
operation provides fast transient response and
" 0.1µA Shutdown Mode
eases loop stabilization. Fault condition
" Fixed 1.4MHz Frequency
protection includes cycle-by-cycle current limiting
" Thermal Shutdown
and thermal shutdown.
" Cycle-by-Cycle Over Current Protection
The MP2360 requires a minimum number of
" Wide 4.5V to 24V Operating Input Range
readily available standard external components.
" Output Adjustable from 0.81V to 15V
The MP2360 is available in a 2mm x 2mm QFN8
" Available in 2x2 QFN8 Packages
package.
APPLICATIONS
EVALUATION BOARD REFERENCE
" Broadband Communications Equipment
Board Number Dimensions
" Digital Entertainment Systems
EV2360DG-00B 1.8 X x 1.6 Y x 0.4 Z
" Distributed Power Systems
" Battery Charger
" Pre-Regulator for Linear Regulators
 MPS and  The Future of Analog IC Technology are Trademarks of Monolithic
Power Systems, Inc.
TYPICAL APPLICATION
Efficiency vs
Load Current
100
3
7
VIN IN BST
CB
VOUT = 3.3V
90
10nF
2
VOUT
SW
3.3V
MP2360
VOUT = 2.5V
80
D1
B230A
70
4 5
EN
OFF ON FB
GND
60
6
VIN = 12V
50
0 0.5 1.0 1.5 2.0
LOAD CURRENT (A)
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EFFICIENCY (%)
TM
MP2360  1.8A, 24V, 1.4MHz STEP-DOWN CONVERTER
PACKAGE REFERENCE ABSOLUTE MAXIMUM RATINGS (1)
Supply Voltage VIN....................................... 26V
VSW.......................................  0.3V to VIN + 0.3V
TOP VIEW
VBS ....................................................... VSW + 6V
All Other Pins.................................  0.3V to +6V
NC 1 8 NC
Junction Temperature...............................150°C
Lead Temperature ....................................260°C
SW 2 7 BST
Storage Temperature .............. 65°C to +150°C
IN 3 6 GND
Recommended Operating Conditions (2)
EN 4 5 FB
Supply Voltage VIN........................... 4.5V to 24V
Output Voltage VOUT ...................... 0.81V to 15V
QFN8
Operating Temperature ............. 40°C to +85°C
(2mm x 2mm)
Thermal Resistance (3) ¸JA ¸JC
2x2 QFN8 ............................... 80 ...... 16... °C/W
Part Number* Package Temperature
Notes:
MP2360DG 2x2 QFN8  40°C to +85°C
1) Exceeding these ratings may damage the device.
2) The device is not guaranteed to function outside of its
* For Tape & Reel, add suffix  Z (eg. MP2360DG Z)
For RoHS compliant packaging, add suffix  LF (eg.
operating conditions.
MP2360DG LF Z)
3) Measured on approximately 1 square of 1 oz copper.
ELECTRICAL CHARACTERISTICS
VIN = 12V, TA = +25°C, unless otherwise noted.
Parameters Symbol Condition Min Typ Max Units
Feedback Voltage VFB 4.5V d" VIN d" 24V 0.790 0.810 0.830 V
Feedback Current IFB VFB = 0.8V 10 nA
Switch On-Resistance (4) RDS(ON) 0.3 &!
Switch Leakage VEN = 0V, VSW = 0V 0 10 µA
Current Limit (4) Duty Cycle = 40% 2.0 2.5 A
Oscillator Frequency fSW VFB = 0.6V 1.4 MHz
Fold-back Frequency VFB = 0V 460 KHz
Maximum Duty Cycle VFB = 0.6V 87 %
Minimum On-Time (4) tON 100 ns
Under-Voltage Lockout Threshold Rising 2.5 2.8 3.1 V
Under-Voltage Lockout Threshold Hysteresis 150 mV
EN Input Low Voltage 0.4 V
EN Input High Voltage 1.2 V
VEN = 2V 2.1
EN Input Current µA
VEN = 0V 0.01
Supply Current (Shutdown) VEN = 0V 0.1 1.0 µA
Supply Current (Quiescent) VEN = 2V, VFB = 1V 0.8 1.0 mA
Thermal Shutdown (4) 150 °C
Note:
4) Guaranteed by design.
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TM
MP2360  1.8A, 24V, 1.4MHz STEP-DOWN CONVERTER
PIN FUNCTIONS
Pin # Name Description
1, 8 NC No Connect.
2 SW Switch Output.
Supply Voltage. The MP2360 operates from a +4.5V to +24V unregulated input. C1 is needed
3 IN
to prevent large voltage spikes from appearing at the input.
4 EN On/Off Control Input. Pull above 1.2V to turn the device on.
Feedback. An external resistor divider from the output to GND, tapped to the FB pin sets the
output voltage. To prevent current limit run away during a short circuit fault condition the
5 FB
frequency foldback comparator lowers the oscillator frequency when the FB voltage is below
250mV.
Ground. This pin is the voltage reference for the regulated output voltage. For this reason care
6 GND must be taken in its layout. This node should be placed outside of the D1 to C1 ground path to
prevent switching current spikes from inducing voltage noise into the part.
Bootstrap. This capacitor is needed to drive the power switch s gate above the supply voltage. It
7 BST is connected between SW and BST pins to form a floating supply across the power switch
driver.
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 12V, VOUT = 3.3V, TA = +25°C, unless otherwise noted.
Efficiency vs Efficiency vs Current Limit vs
Load Current Load Currents Duty Cycle
100
100 4.0
VOUT = 12V
VOUT = 5V
3.5
90
90
3.0
VOUT = 5V
80
80
2.5
VOUT = 2.5V
VOUT = 2.5V
70 2.0
70
1.5
60
60
1.0
50
50
0.5
VIN = 12V VIN = 24V
0
40
40
0 0.5 1.0 1.5 2.0 2.5 0 0.5 1.0 1.5 2.0 2.5 0 20 40 60 80 100
LOAD CURRENT (A) LOAD CURRENT (A) DUTY CYCLE (%)
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EFFICIENCY (%)
EFFICIENCY (%)
CURRENT LIMIT (A)
TM
MP2360  1.8A, 24V, 1.4MHz STEP-DOWN CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = 12V, VOUT = 3.3V, TA = +25°C, unless otherwise noted.
Load Transient Test
Steady State Test
VIN = 12V, VOUT = 3.3V
VIN = 12V, VOUT = 3.3V, IOUT = 0.5A
VOUT
VOUT AC Coupled
20mV/div. 200mV/div.
VSW
IL
10V/div.
1A/div.
ILOAD
1A/div.
IL
500mA/div.
400ns/div.
Start-up through Enable
Start-up through Enable
Shut-down through Enable
VIN = 12V, VOUT = 3.3V,
VIN = 12V, VOUT = 3.3V, No Load
VIN = 12V, VOUT = 3.3V, No Load
IOUT = 2A Resistive Load
VEN
VEN VEN
5V/div.
5V/div. 5V/div.
VOUT
2V/div.
VOUT
VOUT
2V/div. 2V/div.
VSW
VSW
VSW
10V/div.
10V/div.
10V/div.
IL
IL
IL
2A/div.
2A/div.
2A/div.
Shut-down through Enable Short Circuit Recovery
Short Circuit Entry
VIN = 12V, VOUT = 3.3V, VIN = 12V, VOUT = 3.3V
VIN = 12V, VOUT = 3.3V
IOUT = 2A Resistive Load
VEN
5V/div.
VOUT
VOUT
2V/div.
VOUT
2V/div.
2V/div.
VSW
10V/div.
IL
IL
2A/div.
IL
2A/div.
2A/div.
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TM
MP2360  1.8A, 24V, 1.4MHz STEP-DOWN CONVERTER
OPERATION
The MP2360 is a current mode buck regulator. If the sum of the Current Sense Amplifier output
That is, the EA output voltage is proportional to and the Slope Compensation signal does not
the peak inductor current. exceed the EA output for a whole cycle, then
the falling edge of the CLK resets the Flip-Flop.
At the beginning of a cycle, M1 is off. The EA
output voltage is higher than the current sense The output of the Error Amplifier integrates the
amplifier output, and the current comparator s voltage difference between the feedback and
output is low. The rising edge of the 1.4 MHz the 0.81V bandgap reference. The polarity is
CLK signal sets the RS Flip-Flop. Its output such that a FB pin voltage lower than 0.8V
turns on M1 thus connecting the SW pin and increases the EA output voltage. Since the EA
inductor to the input supply. output voltage is proportional to the peak
inductor current, an increase in its voltage also
The increasing inductor current is sensed and
increases current delivered to the output.
amplified by the Current Sense Amplifier. Ramp
compensation is summed to Current Sense
Amplifier output and compared to the Error
Amplifier output by the PWM Comparator.
When the sum of the Current Sense Amplifier
output and the Slope Compensation signal
exceeds the EA output voltage, the RS Flip-
Flop is reset and the M1 is turned off. The
external Schottky rectifier diode (D1) conducts
the inductor current.
IN
CURRENT SENSE
D
AMPLIFIER
x20
REGULATOR
BST
EN
REGULATOR
OSCILLATOR
Q M1
S DRIVER
1.4MHz
+
R
--
SW
R
CURRENT
1pF
LIMIT
COMPARATOR
27pF
REFERENCE
+
+EA
--
--
FB
PWM
ERROR
COMPARATOR
AMPLIFIER
GND
Figure 1 Functional Block Diagram
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--
+
TM
MP2360  1.8A, 24V, 1.4MHz STEP-DOWN CONVERTER
APPLICATION INFORMATION
Setting Output Voltage Selecting the Input Capacitor
The external resistor divider is used to set the The input capacitor reduces the surge current
output voltage (see the schematic on front drawn from the input and the switching noise from
page). The feedback resistor R1 also sets the the device. The input capacitor impedance at the
feedback loop bandwidth with the internal switching frequency should be less than the input
compensation capacitor (see Figure 1). R2 can source impedance to prevent high frequency
be determined by: switching current from passing through the input.
Ceramic capacitors with X5R or X7R dielectrics
R1
R2 =
are highly recommended because of their low
VOUT
- 1
ESR and small temperature coefficients. For most
0.81V
applications, a 10µF capacitor is sufficient.
Table 1 Resistor Selection for Common
Selecting the Output Capacitor
Output Voltages
The output capacitor keeps output voltage ripple
VOUT (V) R1 (k&!) R2 (k&!)
small and ensures loop stability. The output
capacitor impedance should be low at the
1.8 80.6 (1%) 64.9 (1%)
switching frequency. Ceramic capacitors with
2.5 49.9 (1%) 23.7 (1%)
X5R or X7R dielectrics are recommended for their
3.3 49.9 (1%) 16.2 (1%)
low ESR characteristics. For most applications, a
5 49.9 (1%) 9.53 (1%)
22µF ceramic capacitor will be sufficient.
PC Board Layout
Selecting the Inductor
The high current paths (GND, IN and SW) should
A 1µH to 10µH inductor with a DC current rating
be placed very close to the device with short,
of at least 25% percent higher than the
direct and wide traces. The input capacitor needs
maximum load current is recommended for
to be as close as possible to the IN and GND
most applications. For highest efficiency, the
pins. The external feedback resistors should be
inductor s DC resistance should be less than
placed next to the FB pin. Keep the switch node
200m&!. For most designs, the required
traces short and away from the feedback network.
inductance value can be derived from the
following equation.
External Bootstrap Diode
VOUT × (VIN - VOUT )
It is recommended that an external bootstrap
L =
diode be added when the input voltage is no
VIN × "IL × fOSC
greater than 5V or the 5V rail is available in the
Where "IL is the inductor ripple current.
system. This helps improve the efficiency of the
regulator. The bootstrap diode can be a low cost
Choose an inductor with a rating current of
one such as IN4148 or BAT54.
approximately 30% higher than the maximum
load current if the maximum load current is
5V (External) or
VIN (4.5 to 5V)
e"1.8A. The maximum inductor peak current is
calculated from:
7
BST
"IL
IL(MAX) = ILOAD +
10nF
MP2360
2
2
SW
Under light load conditions below 100mA, a
larger inductance is recommended for improved
Figure 2 External Bootstrap Diode
efficiency. See Table 2 for suggested inductors.
This diode is also recommended for high duty cycle
VOUT
operation (when >65%) applications.
VIN
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TM
MP2360  1.8A, 24V, 1.4MHz STEP-DOWN CONVERTER
Table 2 Suggested Surface Mount Inductors
Current Rating Dimensions
Manufacturer Part Number Inductance(µH) Max DCR(&!)
(A) L x W x H (mm3)
Wurth Electronics 7447785004 4.7 0.060 2.5 5.9 x 6.2 x 3.3
Toko A916CY-4R7M 4.7 0.026 2.5 6.2 x 6.3 x 3.5
Coiltronics DR73-4R7 4.7 0.03 3 6.0 x 7.6 x 3.5
TYPICAL APPLICATION CIRCUIT
3 7
VIN IN BST
C4
10nF
4 2
VOUT
EN MP2360 SW
OFF ON
3.3V
D1
B230A
5
FB
GND
6
Figure 3 1.4MHz, 3.3V Output Step-Down Converter
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TM
MP2360  1.8A, 24V, 1.4MHz STEP-DOWN CONVERTER
PACKAGE INFORMATION
2mm x 2mm QFN8
1.90 PIN 1 ID
0.25 0.45
2.10 SEE DETAIL A
0.45 0.65
PIN 1 ID
MARKING
0.18
8 1
0.30
1.90
0.50 1.05
PIN 1 ID
2.10
BSC 1.25
INDEX AREA
54
TOP VIEW BOTTOM VIEW
PIN 1 ID OPTION A PIN 1 ID OPTION B
R0.20 TYP. R0.20 TYP.
0.80
1.00
0.20 REF
0.00
0.05
SIDE VIEW DETAIL A
NOTE:
1.90
0.60
0.70 1) ALL DIMENSIONS ARE IN MILLIMETERS.
2) EXPOSED PADDLE SIZE DOES NOT INCLUDE MOLD FLASH.
3) LEAD COPLANARITY SHALL BE 0.10 MILLIMETER MAX.
0.25
4) DRAWING CONFORMS TO JEDEC MO-229, VARIATION VCCD-3.
5) DRAWING IS NOT TO SCALE.
1.20
0.50
RECOMMENDED LAND PATTERN
NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third
party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not
assume any legal responsibility for any said applications.
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