JW5250A

1A, 6V，1.5MHz, 40uA IQ

Synchronous Step-Down Converter
Preliminary Specifications Subject to Change without Notice

DESCRIPTION
FEATURES
The JW ®5250A is a monolithic buck switching  2.7V to 6.0V operating input range
regulator based on constant on-time (COT)  Up to 1A output current
control for fast transient response. Operating with  Up to 92% peak efficiency
an input range of 2.7V-6.0V, the JW5250A  Internal soft-start
delivers 1A of continuous output current with  1.5MHz switching frequency
integrated P-Channel and N-Channel MOSFETs.
 Input under voltage lockout
The internal synchronous power switches provide
 Hot-plug in protection
high efficiency. At light loads, the regulator
 Short circuit protection
operate in low frequency to maintain high
 Thermal protection
efficiency and low output ripples.
 Available in a SOT23-5 package
The JW5250A guarantees robustness with hiccup
output short-circuit protection, FB short-circuit APPLICATIONS
protection, start-up current run-away protection,  5V or 3.3V Point of Load Conversion
input under voltage lockout and hot-plug in, and  Set Top Boxes
thermal protection.  Telecom/Networking Systems
The JW5250A is available in a 5-pin SOT23-5  Storage Equipment
package, which provides a compact solution with  GPU/DDR Power Supply
minimal external components.
Company’s Logo is Protected, “JW” and “JOULWATT” are Registered
Trademarks of JoulWatt technology Inc.

TYPICAL APPLICATION

L
VIN VO U T
V IN SW

C3

C1 OFF ON
EN JW 5250A FB
R2

C2
GND R3

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ORDER INFORMATION

DEVICE1) PACKAGE TOP MARKING2) ENVIRONMENTAL3)

JWM3□
JW5250ASOTA#TR SOT23-5 Green
YW□□□

Note：
JW # TR

1) Tape and Reel (If TR is not shown, it means Tube)

Package Code
Part No.
YW
JW
Lot number
2) Line1: Product code Line2:
Week code
Joulwatt LOGO Year code

3) All Joulwatt products are packaged with Pb-free and Halogen -free materials and compliant to RoHS standards .

PIN CONFIGURATION

TOP VIEW

EN 1 5 FB

GND 2

SW 3 4 VIN

SOT23-5

ABSOLUTE MAXIMUM RATING1）

EN, FB Pins ...................................................................................................................-0.3V to 7.0 V
VIN, SW Pins .....................................................................-0.3V(-3V for 20ns) to 7.0V(7.1V for 70ns)
Junction Temperature. 2) ...................................................................................................................150ºC
Lead Temperature ......................................................................................................................260ºC
Storage Temperature .................................................................................................. -65ºC to +150ºC
ESD Susceptibility (Human Body Model) ......................................................................................... 3.5kV

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RECOMMENDED OPERATING CONDITIONS3）

Input Voltage VIN ................................................................................................................2.7V to 6.0V
Output Voltage VOUT..................................................................................................................0.6V to VIN
Operating Junction Temperature….....................................................................................-40ºC to 125ºC

THERMAL PERFORMANCE4） θJA θJc

SOT23-5 ..............................................................................................................................105....27ºC/W
Note：
1) Exceeding these ratings may damage the device. These stress ratings do not imply function operation of the device
at any other conditions beyond those indicated under RECOMMENDED OPERATING CONDITIONS.
2) The JW5250A includes thermal protection that is intended to protect the device in overload conditions. Continuous
operation over the specified absolute maximum operating junction temperature may damage the device.
3) The device is not guaranteed to function outside of its operating conditions.
4) Measured on a two-layer JW5250A Evaluation Board at TA=25℃.

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ELECTRICAL CHARACTERISTICS

VIN=5V, TA=25℃, unless otherwise stated.

Item Symbol Condition Min. Typ. Max. Units
VIN Under Voltage Lockout Threshold VIN_UVLO VIN rising 2.3 2.5 2.7 V
VIN Under Voltage Lockout Hysteresis VIN_UVLO_HYST VIN falling 200 mV
VIN Hot-plug in Protection Threshold VIN_OVP VIN rising 6.1 6.6 V
VIN Hot-plug in Protection Hysteresis VIN_OVP_HYST VIN falling 600 mV
Shutdown Current ISHDN VIN=6.0V, VEN=0V 0.1 1 μA
VEN=5V, IOUT=0A,
Quiescent Current IQ 40 70 μA
VFB=VREF*105%
Regulated Feedback Voltage VFB 2.7V<VIN<6.0V 0.588 0.6 0.612 V
PFET On Resistance5) RDSON_P VIN=3.6V, ISW=200mA 260 mΩ
NFET On Resistance5) RDSON_N VIN=3.6V, ISW=-200mA 190 mΩ
VIN=6.0V, VEN=0V,
PFET Leakage Current ILEAK_P 1 uA
VSW=0V
VIN=6.0V, VEN=0V,
NFET Leakage Current ILEAK_N 1 uA
VSW=6.0V
PFET Current Limit5) ILIM_TOP 1.6 2.0 2.4 A
NFET Current Limit5) ILIM_BOT 1.2 1.5 2 A
Switch Frequency5) FSW IOUT=1A 1.5 MHz
Minimum On Time5) TON_MIN 100 ns
Maximum Duty Cycle5) DMAX 100 %
EN Input Logic High Voltage VEN_H VEN rising, FB=0.3V 1.5 V
EN Input Logic Low Voltage VEN_L VEN falling, FB=0.3V 0.4 V
Thermal Shutdown Threshold5) TSHDN 150 ℃
Thermal Shutdown Hysteresis5) THYST 20 ℃
Note:
5) Guaranteed by design

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PIN DESCRIPTION

Name Description
1 EN Drive EN pin high to turn on the regulator and low to turn off the regulator.
2 GND Ground pin.
SW is the switching node that supplies power to the output. Connect the
3 SW
output LC filter from SW to the output load.
Input voltage pin. VIN supplies power to the IC. Connect a 2.7V to 6.0V
4 VIN supply to VIN and bypass VIN to GND with a suitably large capacitor to
eliminate noise on the input to the IC.
Output feedback pin. FB senses the output voltage and is regulated by the
5 FB
control loop to 0.6V. Connect a resistive divider at FB.

BLOCK DIAGRAM

VIN

Current
Sensor

On Timer Ton -
Adjustment

+
Error
0.6V + Amplifier SW
Logic
FB - Control

Current
Sensor

1.5V +

GND

EN -

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TYPICAL PERFORMANCE CHARACTERISTICS

VIN =5V, VOUT = 1.8V, L = 1.5μH, C2 = 22μF, TA = +25°C, unless otherwise noted

Steady State Test Startup through Enable Shutdown through Enable

VIN=5V, VOUT=1.8V VIN=5V, VOUT=1.8V VIN=5V, VOUT=1.8V
IOUT=1A IOUT=1A(Resistive load) IOUT=1A (Resistive load)

VIN
2 V / d iv EN EN
V O U T .A C 2 V / d iv 2 V / d iv
1 0 m V / d iv VO U T VO U T
1 V / d iv 1 V / d iv
SW
SW SW
2 V / d iv
2 V / d iv 2 V / d iv

IL IL
1 A / d iv IL 1 A / d iv
1 A / d iv
8 0 0 u s / d iv 8 0 0 u s / d iv
2 u s / d iv

Heavy Load Operation Medium Load Operation Light Load Operation

1A LOAD 0.5A LOAD 0 A LOAD
VIN VIN VIN
2 V / d iv 2 V / d iv 2 V / d iv
V O U T .A C V O U T .A C
1 0 m V / d iv V O U T .A C
1 0 m V / d iv 1 0 m V / d iv
SW SW SW
2 V / d iv 2 V / d iv 2 V / d iv

IL IL
1 A / d iv 1 A / d iv IL
1 A / d iv
2 u s / d iv 2 u s / d iv 2 m s / d iv

Short Circuit Protection Short Circuit Protection Load Transient

VIN=5V, VOUT=1.8V VIN=5V, VOUT=1.8V LOAD: 0.1A→ 1.0A →0.1A
IOUT=1.0A- Short IOUT = Short-1.0A 2.5A/us, C3=1nF

VIN
VIN
2 V / d iv
2 V / d iv
VO U T V O U T .a c
VO U T
1 V / d iv 5 0 m V / d iv
1 V / d iv

SW
2 V / d iv SW
2 V / d iv
IL
IL
IL 5 0 0 m A / d iv
1 A / d iv
1 A / d iv
4 m s / d iv 1 0 0 u s / d iv
4 m s / d iv

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TYPICAL PERFORMANCE CHARACTERISTICS (continued)

VIN =5V, VOUT = 1.8V, L = 1.5μH, C2 = 22μF, TA = +25°C, unless otherwise noted
Efficiency @ VOUT=1.8V Efficiency @ VOUT=1.2V

100% 100%
95% 95%
90% 90%

Efficiency
85% 85%
Efficiency

80% 80%
75% Vin=5V 75% Vin=5V

70% Vin=4.2V 70% Vin=4.2V

65%
65% Vin=3.3V Vin=3.3V
60%
60%
1 10 100 1000
1 10 100 1000
Output Current (mA) Output Current (mA)

Efficiency @ VOUT=0.8V Load regulation @ VOUT=1.8V

100% 1.0%

90%
0.5%
Load Regulation

Vin=5V
Efficiency

80% Vin=3.3V
0.0%
70% Vin=5V
Vin=4.2V -0.5%
60%
Vin=3.3V
50% -1.0%
1 10 100 1000 0 200 400 600 800 1000
Output Current (mA) Output Current (mA)

Quiescent Current Vs. Input Voltage Shutdown Current Vs. Input Voltage
VIN=2.7V ~ 6V, VEN=2.5V, VFB=0.8V VIN=2.7V ~ 6V, VEN=0V, VFB=0.5V

80 1
Quiescent Current (uA)

70
Shutdown Current (uA)

60 0.5
50
40 0
30
20 -0.5
10
0
-1
2 4 6 8
2 4 6 8
Input Voltage (V) Input Voltage (V)

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FUNCTIONAL DESCRIPTION

The JW5250A is a constant on-time control, P-channel and N-channel MOSFET switches
synchronous, step-down regulator. It regulates are integrated on the JW5250A to down convert
input voltages from 2.7V~6.0V down to an the input voltage to the regulated output voltage.
output voltage as low as 0.6V, and is capable of
Short Circuit Protection
supplying up to 1A of load current.
When output is shorted to ground, the switching
Constant On-time Control
frequency is reduced to prevent the inductor
The JW5250A utilizes constant on-time control current from increasing beyond PFET current
to regulate the output voltage. The output limit. If short circuit condition holds for more than
voltage is measured at the FB pin through a 1024 cycles, both PFET and NFET are forced
resistive voltage divider and the error is off and can be enabled again after 8ms. This
amplified by the internal transconductance error procedure is repeated as long as short circuit
amplifier. condition is not removed.
Output of the internal error amplifier is
FB Short Circuit Protection
compared with the switch current measured
internally to control the output current limit. When FB is shorted to ground and holds for
more 16 cycles, NFET will be turned off after
PFM Mode
inductor current drops to zero, and then both
The JW5250A operates in PFM mode at light PFET and NFET are latched off. When short
load. In PFM mode, switch frequency is circuit condition is removed, it can be recovery.
continuously controlled in proportion to the load
Hot Plug-in Protection
current, i.e. switch frequency decreases when
load current drops to boost power efficiency at When input voltage is greater than hot plug-in
light load by reducing switch-loss, while switch protection threshold, typical 6.8V, it will disable
frequency increases when load current rises, JW5250A. When input voltage decrease below
minimizing output voltage ripples. 6.4V, it will be enabled again.
Shut-Down Mode
Thermal Protection
The JW5250A operates in shut-down mode
When the temperature of the JW5250A rises
when voltage at EN pin is driven below 0.4V. In
above 150°C, it is forced into thermal shut-down.
shut-down mode, the entire regulator is off and
Only when core temperature drops below 130°C
the supply current consumed by the JW5250A
can the regulator becomes active again.
drops below 1uA.

Power Switches

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APPLICATION INFORMATION

Output Voltage Set ILOAD  VOUT VOUT 

C1   1  
fs  V IN VIN  VIN 
The output voltage is determined by the resistor
divider connected at the FB pin, and the voltage where C1 is the input capacitance value, fs is the
ratio is: switching frequency, △VIN is the input ripple
current.
R3
VFB VOUT 
R2  R3 The input capacitor can be electrolytic, tantalum
or ceramic. To minimizing the potential noise, a
where VFB is the feedback voltage and VOUT is
the output voltage. small X5R or X7R ceramic capacitor, i.e. 0.1uF,
should be placed closer than 3mm to the IC as
Choose R3 around 10KΩ, and then R2 can be
calculated by: possible when using electrolytic capacitors.

 VOUT  A 10uF/0805/10V~22uF/0805/10V ceramic

R2 R3    1
 0.6 V  capacitor is recommended in typical application.

The following table lists the recommended Output Capacitor

values.
The output capacitor is required to maintain the
DC output voltage, and the capacitance value
VOUT(V) R2(KΩ) R3(KΩ)
determines the output ripple voltage. The output
1.2 10 10 voltage ripple can be calculated by:
1.8 20 10 VOUT  VOUT 
   RESR  8  f  C 
1
2.5 31.6 10 V OUT  1 
fs  L  VIN   s 2
3.3 49.9 11
where C2 is the output capacitance value and
Input Capacitor RESR is the equivalent series resistance value of
The input capacitor is used to supply the AC the output capacitor.
input current to the step-down converter and The output capacitor can be low ESR
maintaining the DC input voltage. The ripple electrolytic, tantalum or ceramic, which lower
current through the input capacitor can be ESR capacitors get lower output ripple voltage.
calculated by:
The output capacitors also affect the system
VOUT  VOUT 
stability and transient response, and a
IC1 ILOAD   1  
VIN  VIN 
22uF/0805/6.3V~44uF/0805/6.3V ceramic
where ILOAD is the load current, VOUT is the capacitor is recommended in typical application.
output voltage, VIN is the input voltage. Inductor
Thus the input capacitor can be calculated by The inductor is used to supply constant current
the following equation when the input ripple to the output load, and the value determines the
voltage is determined. ripple current which affect the efficiency and the
output voltage ripple. The ripple current is
typically allowed to be 30% of the maximum

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switch current limit, thus the inductance value 2. Put the feedback trace as far away from the
can be calculated by: inductor and noisy power traces as possible.

VOUT  VOUT  3. The ground plane on the PCB should be as

L  1  
fs  I L  VIN  large as possible for better heat dissipation.

where VIN is the input voltage, VOUT is the Layout Example

output voltage, fs is the switching frequency,
and △ IL is the peak-to-peak inductor ripple
current. Divider reisistance

PCB Layout Note EN 1 5 FB

The following advice should be considered when GND 2

laying out a printed circuit board for the JW5250A.

SW 3 4 VIN

1. Place the input decoupling capacitor as Ouput Capacitor

close to JW5250A (VIN pin and PGND) as Input Decoupling Capacitor

possible to eliminate noise at the input pin.

The loop area formed by input capacitor and
GND must be minimized. IC cannot work
well when VIN pin is interfered by noise.

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External Components Suggestion:

VOUT(V) R2 (kΩ) R3 (kΩ) C3(nF) L(uH) C2(uF)

1 6.8 10.2 NC~1 1~2.2 20~44

1.2 10 10 NC~1 1~2.2 20~44
1.8 20 10 NC~1 1~2.2 20~44
3.3 49.9 11 NC~1 1~2.2 20~44

Vout

R2
C3
FB
JW 5 2 5 0 A
R3

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REFERENCE DESIGN

Reference 1：
VIN : 3.3V ~ 6.0 V
VOUT: 3.3V
IOUT : 0~1A

L 1.5 u H
VIN VO U T
V IN SW
3 .3 V ~ 6 .0 V 3 .3 V /1 A

C1 C3
10uF OFF ON
EN JW 5250A
R 2 4 6 .4 k

C2
GND FB
R 3 1 0 .2 k 22μF

Reference 2：
VIN : 2.7V ~ 6.0 V
VOUT: 1.8V
IOUT : 0~1A

L 1.5 u H
VIN VO U T
V IN SW
2 .7 V ~ 6 .0 V 1 .8 V /1 A

C1
10uF C3
OFF ON
EN JW 5250A
R 2 20k

C2
GND FB 22μF
R 3 10k

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TAPE AND REEL INFORMATION

Reel UNIT: mm

W1

W4
φ

W2

Package Diameter Thickness Width W4

Ф W1 W2
SOT23-5 178±2 12.30±2 9.5±2 60±2

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Carrier Tape UNIT: mm

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PACKAGE OUTLINE

SOT23-5 UNIT: mm

D
M IL L IM E T E R
SYM BOL
A2 A M IN NOM MAX
θ
c A 1 .0 5 1 .1 5 1 .2 5
A1 L
A1 0 0 .0 5 0 .1 5

A2 0 .9 5 1 .1 0 1 .2 0

b1 b 0 .2 0 0 .4 0 0 .6 0

b1 0 .6 0

c 0 .0 5 — 0 .2 1

D 2 .7 2 2 .9 2 3 .1 2
E2
E1 E E 2 .6 0 2 .8 0 3 .0 0

E1 1 .4 0 1 .6 0 1 .8 0

E2 2 .4 0
E3
E3 0 .8 0
e1
e 0 .9 5 （ B S C )
b e Recommended Pad Layout
e1 0 .9 5 （ T Y P )

L 0 .3 0 0 .4 5 0 .6 0

θ 0° — 8°

QUADRANT ASSIGNMENTS FOR PIN 1 ORIENTATION IN TAPAE

Sprocket Holes

1 2 1 2 1 2

3 4 3 4 3 4

Procket Quadrants

Package Type Pin1 Quadrant

SOT23-5 3

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IMPORTANT NOTICE

 Joulwatt Technology Inc. reserves the right to make modifications, enhancements, improvements,

corrections or other changes without further notice to this document and any product described herein.

 Any unauthorized redistribution or copy of this document for any purpose is strictly forbidden.

 Joulwatt Technology Inc. does not warrant or accept any liability whatsoever in respect of any products

purchased through unauthorized sales channel.

Copyright © 2019 JW5250A Incorporated.

All rights are reserved by Joulwatt Technology Inc.

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