JW5068A

26V/8A
Sync. Step-Down Converter
Parameters Subject to Change Without Notice

DESCRIPTION FEATURES
The JW ®5068A is a monolithic buck switching  4V to 26V operating input range
regulator based on I2 architecture for fast 8A continuous / 16A peak output current
transient response. Operating with an input range  Up to 95% efficiency
of 4V~26V, JW5068A delivers 8A of continuous  High efficiency at light load
output current with two integrated N-Channel  500kHz switching frequency
MOSFETs. The internal synchronous power  External bypass input
switches provide high efficiency without the use of  Programmable valley current limit
an external Schottky diode. At light loads, the  Power good indicator
regulator operates in low frequency to maintain  Input under voltage lockout
 Output discharge function
high efficiency and low output ripples.
 Output Over Voltage latch off protection
JW5068A guarantees robustness with output
 Output short protection
short protection, thermal protection, current
 Thermal protection
run-away protection, and input under voltage
 Available in QFN3X3-20 package
lockout.
JW5068A is available in QFN3X3-20 package, APPLICATIONS
which provide a compact solution with minimal
 Industrial and commercial low power system
external components.
 Notebook
Company’s Logo is Protected, “JW” and “JOULWATT” are Registered
Trademarks of JoulWatt technology Inc.  LDO monitors and TVs
 Green Electronics/ Appliances

TYPICAL APPLICATION
8A Step-down Regulator
CBST

Vin L
Vout
VIN BST SW
R1 C2 R4

EN
FB
R3
CIN ILMIT JW5068A BYP
VBYP
COUT
VCC R2
PG CBYP
RPG
C1
PGND AGND

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ORDER INFORMATION
1) 2)
DEVICE PACKAGE TOP MARKING

JW5068A
JW5068AQFNF#TRPBF QFN3X3-20
XXXXXX
Notes：

2) Line 1 of top marking means Part No., and the line 2 of top marking means Date Code.

PIN CONFIGURATION
TOP VIEW

ABSOLUTE MAXIMUM RATING1）

VIN, EN, PG, SW, ILMT Pin.................................................................................................... -0.3V to 28V
BST Pin ...................................................................................................................... SW-0.3V to SW+5V
All other Pins ............................................................................................................................ -0.3V to 6V
Junction Temp. 2) 3) ............................................................................................................................150ºC
Lead Temperature .............................................................................................................................260ºC
ESD Susceptibility (Human Body Model) ............................................................................................. 2kV

RECOMMENDED OPERATING CONDITIONS

Input Voltage VIN ....................................................................................................................... 4V to 26V
Output Voltage Vout ............................................................................................................0.8V to VIN-3V

THERMAL PERFORMANCE4） θJA θJc

QFN3*3-20.............................................................................................................................30....4.5ºC/W
Note：
1) Exceeding these ratings may damage the device.
2) The JW5068A guarantees robust performance from -40°C to 150°C junction temperature. The junction temperature
range specification is assured by design, characterization and correlation with statistical process controls.
3) The JW5068A includes thermal protection that is intended to protect the device in overload conditions. Thermal
protection is active when junction temperature exceeds the maximum operating junction temperature. Continuous
operation over the specified absolute maximum operating junction temperature may damage the device.
4) Measured on JESD51-7, 4-layer PCB.

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ELECTRICAL CHARACTERISTICS

VIN=12V, TA=25℃，Unless otherwise stated.

Item Symbol Conditions Min. Typ. Max. Unit
VIN Under Voltage Lock-out Threshold VIN_MIN VIN rising 3 V
VIN Under voltage Lockout Hysteresis VIN_MIN_HYST 200 mV
Shutdown Current ISD VEN=0V 1 μA
Supply Current IQ VEN=5V, VFB=1.2V 60 μA
EN Input High Voltage VEN_H 1.8 V
EN Input Low Voltage VEN_L 1.5 V
Feedback Voltage VFB 4V<VVIN<26V 594 600 606 mV
Top Switch Resistance5) RDS(ON)T 20 mΩ
5)
Bottom Switch Resistance RDS(ON)B 10 mΩ
VIN=26V, VEN=0V,
Top Switch Leakage Current ILEAK_TOP 1 μA
VSW=0V
VIN=26, VEN=0V,
Bottom Switch Leakage Current ILEAK_BOT 1 μA
VSW=26V
ILIM =”0” 8 A
Bottom Switch Current Limit ILIM ILIM =Floating 12 A
ILIM =”1” 16 A
ILMIT Rising Threshold VLIMTH VCC-0.8 VCC V
ILMIT Falling Threshold VLIMTL 0.8 V
5)
Minimum On Time TON_MIN 100 ns
5)
Minimum Off Time TOFF_MIN VFB=0.4V 100 ns
Discharge FET Ron RDIS 50 Ω
Soft-Start Time TSS 400 us
VCC Output VCC VIN=4V 4.9 5 5.1 V
Power Good Threshold PGD_TH FB falling 88% 90% 92% VREF
Power Good Hysteresis PGD_HYS 5% VREF
5)
Power Good Delay Time PGD_DLY 200 us
Power Good Sink Current IPG PG=0.5V 8 mA
Output Over-voltage Threshold VOUT Rising 115% 120% 125% VREF
Output Over-voltage Hysteresis 5% VREF
Output Over-voltage Delay Time 20 us
Output Under-voltage Threshold VFB Falling 60% 65% 70% VREF
FB forced below
Output Under-voltage Delay Time 200 us
UV threshold
Bypass Switch Ron RBYP 3 Ω
Bypass Switch Turn-on Voltage VBYP_ON 4.5 4.7 V

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VIN=12V, TA=25℃，Unless otherwise stated.

Item Symbol Conditions Min. Typ. Max. Unit
Bypass Switch Switchover Hysteresis VBYP_HYS 0.2 V
Bypass Switch OVP VBYP_OVP 120% VCC
Thermal Shutdown5) TTSD 150 °C
5)
Thermal Shutdown hysteresis TTSD_HYST 15 °C

Note：
5) Guaranteed by design.

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PIN DESCRIPTION

Pin Name Description

Connect a 0.1uF capacitor between BST and SW pin to supply current for the top switch
1 BST
driver.
Input voltage pin. VIN supplies power to the IC. Connect a 4V to 26V supply to VIN and
2,3,4,5 VIN
bypass VIN to GND with a suitably large capacitor to eliminate noise on the input to the IC.
SW is the switching node that supplies power to the output. Connect the output LC filter
6,19,20 SW
from SW to the output load.
7,8,EP GND Ground pin
Power good monitor output. This is an open-drain output so a resistor should be
9 PG
connected at this pin to the VCC pin.
11 EN Enable Control. Pull this pin high to turn on the Buck. Do not leave this pin floating.
10,12,16 NC
Current Limit Setting Pin. The current limit is set to 8A, 12A or 16A when this pin is pull low,
13 ILMT
floating or pull high respectively.
Output feedback pin. FB senses the output voltage and is regulated by the control loop to
14 FB
0.6V. Connect a resistive divider at FB.
Bypass input for the internal LDO. BYP is externally connected to the output of switching
15 BYP regulator. When the BYP voltage rises above the bypass switch turn-on threshold, the
power supply of the internal LDO regulator changes to the external source.
5V Linear Regulator Output for Internal Control Circuit. A capacitor (typical 4.7uF) should
17 VCC
be connected to AGND. Don’t connect to external Load.
18 AGND Signal ground pin.

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BLOCK DIAGRAM

PG VIN
+
0.54V
+

Current
- Sensor

-
VCC
AGND

On Timer BST
Adjustment

FB -
SW
FB
0.6V + Comparator Logic
Control

0.8V +

EN - Current
Sensor

GND

VIN

ILMT

5V LDO VCC

4.7V +

BYP -

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TYPICAL PERFORMANCE CHARACTERISTICS

Vin =12V, Vout = 3.3V, L = 1.5μH, Cout = 5*22μF, C2=10pF,R4=0，TA = +25°C, unless otherwise noted

Steady State Test Startup through Enable Shutdown through Enable

VIN=12V, Vout=3.3V VIN=12V, Vout=3.3V VIN=12V, Vout=3.3V
Iout=8A Iout=8A(Resistive load) Iout=3A (Resistive load)

Vin
5V/div EN EN
Vo.AC 5V/div 5V/div
20mV/div Vo
Vo
2V/div 2V/div
SW SW
SW 5V/div 5V/div
5V/div

IL IL IL
2A/div 5A/div 5A/div

2us/div 800us/div 2us/div

Heavy Load Operation Medium Load Operation Light Load Operation

8A LOAD 4A LOAD 0.4 A LOAD

Vin Vin
Vin
5V/div 5v/div
5V/div
Vo.AC Vo.AC
20mV/div 20mV/div Vo.AC
50mV/div
SW
SW SW
5V/div
5V/div 5V/div

IL IL IL
2A/div 2A/div 2A/div
2us/div 2us/div 4us/div

Short Circuit Protection Short Circuit Protection Load Transient

VIN=12V, Vout=3.3V VIN=12V, Vout=3.3V C2=10pF,R4=0k
Iout=0A- Short Iout= 8A- Short 0.8A LOAD → 8A LOAD → 0.8A LOAD

Vin
5V/div Vin
5V/div Vo.AC
Vo Vo 50mV/div
2V/div 2V/div
SW
SW 5V/div
5V/div
IL
IL IL
5A/div
5A/div 5A/div

100us/div 20ms/div 100us/div

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FUNCTIONAL DESCRIPTION

JW5068A is a synchronous step-down regulator The JW5068A’s EN is used to control converter,

based on I2 control architecture. It regulates the enable voltage (EN) has low and high
input voltages from 4V to 26V down to an output threshold voltage. When VEN is below its high
voltage as low as 0.6V, and is capable of threshold voltage, the IC enters shutdown
supplying up to 8A continuous,16A peak load mode. When VEN exceeds its high threshold
current. voltage, the converter is fully operational. In
shutdown mode, the entire regulator of
Power Switch
JW5068A is off.
N-Channel MOSFET switches are integrated on
Power Good
the JW5068A to down convert the input voltage
to the regulated output voltage. Since the top The JW5068A has power-good (PG) output.
MOSFET needs a gate voltage great than the The PG pin is the open drain of a MOSFET.
input voltage, a boost capacitor connected Connect to Vcc or another voltage source
between BST and SW pins is required to drive through a resistor. When the output voltage
the gate of the top switch. The boost capacitor is becomes within -10% of the target value,
charged by the internal 3.7V rail when SW is internal comparators detect power good state
low. and the power good signal becomes high. If the
feedback voltage goes under 10%of the target
Vin Under-Voltage Protection
value, the power good signal becomes low.
In addition to the enable function, the JW5068A
Output Voltage Over-voltage Protection
provides an Under Voltage Lock-out (UVLO)
function that monitors the input voltage. To JW5068A integrates both output over-voltage
prevent operation without fully-enhanced protection and under-voltage protection. If the
internal MOSFET switches, this function inhibits output voltage rises above the regulation level,
switching when input voltage drops below the the high-side MOSFET naturally remains off and
UVLO-falling threshold. The IC resumes the synchronous rectifier will turn on until the
switching when input voltage exceeds the inductor current reaches the zero. If the output
UVLO-rising threshold. voltage exceeds the OVP threshold for longer
than 20 us (typical), the OVP function is
Soft Start
triggered. If the output voltage drops below the
The JW5068A has an internal soft-start function UVP trip threshold for longer than 200 us
to prevent large inrush current and output (typical), the UVP function is triggered.
voltage overshoot when the converter starts up. JW5068A use latch-off mode in OVP and UVP.
The soft-start (SS) automatically begins once When the protection function is triggered, the IC
the chip is enabled. During soft-start, it clamps will shut down. The IC stops switching and is
the ramping of internal reference voltage which latched off. To restart operation, toggle EN or
is compared with FB signal. The typical power the IC off and then on again.
soft-start duration is 0.4ms.
Current Limit
Enable and Disable
The JW5068A current limit is adjustable

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(8A,12A,16A) by ILMT pin and it is a (VCC). When the input voltage of BYP pin is
cycle-by-cycle “ valley ” mechanism, lower than the switch over threshold 4.7V, the
measuring the inductor current through the VCC regulator steps down input voltage to
synchronous rectifier during the off-time while supply both internal circuitry and gate drivers.
the inductor current ramps down. The current is When the input voltage of BYP pin is higher
determined by measuring the voltage between than the switch over threshold 4.7V, an
source and drain of the synchronous rectifier, automatic circuit will change the power source
adding temperature compensation for greater of linear regulator from VIN path to external path,
accuracy. If the current exceeds the current limit, therefore the power dissipation of linear
the turn-on signal of top MOSFET is inhibited regulator will be decrease efficiently. A 4.7uF
until the inductor current ramps down below the ceramic capacitor is recommended to bypass
current limit. Thus, only when the inductor VCC to GND. Do not connect the VCC pin to
current is well below the current limit, another external loads.
on-time is permitted. If the output current
Thermal Protection
exceeds the available inductor current
(controlled by the current limit mechanism), the When the temperature of the JW5068A rises
output voltage will drop. If it drops below the above 150°C, it is forced into thermal protection
output under-voltage protection level, the IC will (OTP). The JW5068A uses latch-off mode in
stop switching to avoid excessive heat. OTP. When the protection function is triggered,
the IC will shut down. The IC stops switching
Linear Regulator (VCC)
and is latched off. To restart operation, toggle
The JW5068A integrates a 5V linear regulator EN or power the IC off and then

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PACKAGE OUTLINE

QFN3X3-20 UNIT: mm

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QFN3X3-20 UNIT: mm

Dimensions In Millimeters Dimensions In Inches

Symbol
Min. Max. Min. Max.
A 0.5 0.6 0.020 0.024
A1 0 0.05 0.000 0.002
A2 0.4 0.016
A3 0.152 REF 0.006
b 0.15 0.25 0.006 0.010
D 3 BSC 0.118 BSC
E 3 BSC 0.118 BSC
e 0.45BSC 0.018 BSC
D2 0.63 0.83 0.025 0.033
E2 0.8 1 0.031 0.039
L 0.3 0.5 0.012 0.020
K 0.65 REF 0.026 REF
K1 0.735 REF 0.029 REF
aaa 0.1 0.004
ccc 0.1 0.004
eee 0.08 0.003
bbb 0.1 0.004
fff 0.1 0.004

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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 © 2017 JW5068A Incorporated.

All rights are reserved by Joulwatt Technology Inc.

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