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Advanced Power
Electronics Corp.
APE8968MP-HF-3
3A Ultra-low Dropout Regulator
Features
Description
The APE8968-HF-3 is a 3A ultra-low dropout linear
regulator, originally designed to provide supply voltages
for front-side-bus termination on motherboards and
NB applications. The IC needs two supply voltages, a
control voltage for the circuitry and a main supply voltage for
power conversion, to reduce power dissipation and provide
extremely low dropout. The APE8968-HF-3 integrates many
functions. A Power-On-Reset (POR) circuit monitors both
supply voltages to prevent incorrect operation. Thermal
shutdown and current limit functions protect the device
against thermal and current over-loads. A POK indicates the
output status with a time delay which is set internally. It can
control another converter for power sequencing. The APE8968
can be also be enabled by other power system. Pulling and
holding the EN pin below 0.4V shuts off the output.
The APE8968-HF-3 is available in an ESOP-8 package which
features the small size of an SO-8 with an exposed pad to reduce
the junction-to-case thermal resistance, making it suitable for
2~3W applications.
Ultra-low Dropout of 0.23V (typical) at 3A
Output Current
Low ESR Output Capacitor (compatible
with Multi-layer Chip Capacitors (MLCC))
Reference Voltage of 0.8V
Fast Transient Response
Adjustable Output Voltage using External Resistors
Power-On-Reset Monitoring on Both
VCNTL and VIN Pins
Internal Soft-Start
Under-Voltage Protection
Current-Limit and Thermal Shutdown Protection
Power-OK Output with a Delay Time
RoHS-compliant halogen-free ESOP-8 Package
with Exposed Pad
Typical Application Circuit
1. Using an Output Capacitor with ESR >20mΩ
R3
1k
VCNTL=5V
6
ON
C1
OFF
7
8
1
5
VIN
VCNTL
VOUT
POK
GND
C3
100uF
4
VOUT
EN
VIN=1.5V
C2
3
0.1uF
2
FB
Vout=1.2V/3A
1uF
R1
1k
APE8968-3
C6
12~48nF
R2
2k
C4
C5
220uF
0.1u
2. Using an MLCC as the Output Capacitor
R3
10k
U2
VCNTL=5V
6
ON
C1
OFF
7
8
1
VCNTL
POK
EN
GND
VIN
VOUT
VOUT
FB
5
VIN=1.5V
C3
3
10uF
4
2
1uF
APE8968-3
Vout=1.2V/3A
R1
39k
C6
C5
56pF
10uF
R2
78k
VOUT=VFB*(1+R1/R2)
VFB = 0.8V
©2011 Advanced Power Electronics Corp. USA
www.a-powerusa.com
201103293-3
1/9
Advanced Power
Electronics Corp.
APE8968MP-HF-3
Absolute Maximum Ratings (at TA =25°C)
VCNTL Supply Voltage(VCNTL) -------------------------- -0.3V to 7V
VIN Supply Voltage(VIN) ---------------------------------- -0.3V to 6V
EN and FB Pin Voltage(VI/O) ----------------------------
-0.3V to VCNTL+0.3V
Power Dissipation(PD) ------------------------------------- 3W
Power Good Voltage(VPOK) ------------------------------- -0.3V to 7V
Storage Temperature Range(TST) ---------------------
-65°C to +150°C
Junction Temperature Range(T J) ----------------------
-40°C To 125°C
Operating Temperature Range (T OP) ------------------ -40°C to +85°C
Thermal Resistance from Junction to Case(Rth JC)
15°C/W
Thermal Resistance from Junction to Ambient(RthJA)
40°C/W
Note: RthJA is measured with the PCB copper area (connected to the exposed pad) of approximately 1.5 in2 (Multi-layer)
Recommended Operating Conditions
VCNTL Supply Voltage(VCNTL) -------------------------- 3V to 5.5V
VIN Supply Voltage(VIN) ---------------------------------- 1.2V to 3.65V
Output Voltage(VOUT) -------------------------------------- 0.8V to VIN-VDROP (VCNTL - VOUT > 1.9V)
Output Current(IOUT) --------------------------------------- 0 to 3A
Ordering Information
Package Type
MP : RoHS-compliant halogen-free ESOP-8
APE8968MP-HF-3TR
Packing TR : Products in ESOP-8 are shipped on tape and reel.
The device is rated MSL3 for moisture sensitivity,
and the reel is packed in a moisture barrier bag.
Pin Configuration
( Top View )
GND
1
FB
2
VOUT
3
VOUT
4
8 EN
Exposed
Pad
7 POK
6
VCNTL
5
VIN
Exposed pad is not connected internally.
ESOP-8
THIS PRODUCT IS SENSITIVE TO ELECTROSTATIC DISCHARGE, PLEASE HANDLE WITH CAUTION.
USE OF THIS PRODUCT AS A CRITICAL COMPONENT IN LIFE SUPPORT OR OTHER SIMILAR SYSTEMS IS NOT AUTHORIZED.
APEC DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED
HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
APEC RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE
RELIABILITY, FUNCTION OR DESIGN.
©2011 Advanced Power Electronics Corp. USA
www.a-powerusa.com
2/9
Advanced Power
Electronics Corp.
APE8968MP-HF-3
Pin Functional Description
FB
Connecting this pin to an external resistor divider provides the feedback voltage to the
regulator. The output voltage set by the resistor divider is determined by:
VOUT = 0.8 x (1 + R1/R2)
where R1 is connected from VOUT to FB with Kelvin sensing and R2 is connected
from FB to GND. A bypass capacitor may be connected in parallel with R1 to improve
load transient response. The recommended R2 and R1 are in the range of 1K~100kΩ.
VIN
Main supply input pin for power conversion. The voltage at this pin is monitored
for Power-On Reset purposes.
VCNTL
Power input pin of the control circuitry. Connecting this pin to a (recommended) +5V
supply voltage provides the bias for the control circuitry. The voltage at this pin is
also monitored for Power-On Reset purposes.
POK
Power-OK signal output pin. This pin is an open-drain output used to indicate the status
of the output voltage by sensing the FB voltage. This pin is pulled low when the rising FB
voltage is not above the VPOK threshold or the falling FB voltage is below the VPOK threshold,
indicating the output is not OK.
EN
Enable control pin. Pulling and holding this pin below 0.4V shuts down the output.
When re-enabled, the IC undergoes a new soft-start cycle. If left open, this pin is
internally pulled up to the VCNTL voltage, enabling the regulator.
VOUT
Output of the regulator. Please connect Pin 3 and Pin 4 using wide tracks. It is essential to
connect an output capacitor to this pin for closed-loop compensation and to improve the
transient response.
©2011 Advanced Power Electronics Corp. USA
www.a-powerusa.com
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Advanced Power
Electronics Corp.
APE8968MP-HF-3
Electrical Characteristics
(VCNTL = 5V, VIN = 1.5V, VOUT = 1.2V, TA=25°C unless otherwise specified)
Parameter
SYM
TEST CONDITION
MIN
TYP
MAX
UNITS
VCNTL POR Threshold
VCNTL
2.5
2.7
2.9
V
VCNTL POR Hysteresis
VCNTL(hys)
-
0.4
-
V
VIN POR Threshold
VIN
0.8
0.9
1
V
VIN POR Hysteresis
VIN(hys)
-
0.5
-
V
EN= VCNTL
-
1
1.8
mA
-
15
30
uA
0.784
0.8
0.816
V
-
0.2
0.5
%
1.2V<VOUT<1.8V
-
0.23
0.28
1.8V≦VOUT<2.5V
-
0.28
0.33
2.5V≦VOUT≦2.8V
-
0.33
0.38
-
50
-
Ω
-
2
4
ms
VCNTL Nominal Supply Current
ICNTL
VCNTL Shuntdown Current
ISD
EN= 0V
Feedback Voltage
VFB
VCNTL=3.0 ~ 5.5V, IOUT=10mA
IOUT=0A ~ 3A
Load Regulation
VDROP
Dropout Voltage
IIOUT == 3A,
3A,
OUT
VVCNTL=5V
=5V
CNTL
VOUT Pull Low Resistance
EN=0V
V
Soft Start Time
TSS
EN Pin Logic High Threshold
Voltage
VENH
Enable
1.2
-
-
VENL
Disable
-
-
0.4
-
50
-
mV
EN=GND
-
10
-
uA
4.3
-
-
A
-
65
-
-
60
-
EN Hysteresis
EN Pin Pull-Up Current
IEN
Current Limit
ILIM
Ripple Rejection
VIN
VCNTL
PSRR
Under-Voltage Threshold
VCNTL=3~5.5V, Tj = -40 ~ 125°C
F=120Hz, IOUT=100mA
V
dB
VFB Falling
-
0.4
-
V
POK Threshold Voltage for Power OK
VPOK
VFB Rising
89%
92%
95%
VFB
POK Threshold Voltage for Power
Not OK
VPNOK
VFB Falling
79%
82%
85%
VFB
-
0.25
0.4
V
ms
POK Low Voltage
POK sinks 5mA
POK Delay Time
Thermal Shutdown Temp
TDELAY
0.8
2
4
TSD
-
150
-
-
50
-
Thermal Shutdown Hysteresis
°C
Block Diagram
N-MOSFET
VIN
VCNTL
EN
Current
Limit
Power -ON
Reset
Enable
+
+
Bandgap
UV
FB
0.4V
+
Thermal
Shutdown
Error
Amp
-
Soft-Start
And
Control Logic
VOUT
Delay
POK
-
GND
94%
Vref
POK
©2011 Advanced Power Electronics Corp.U SA
www.a-powerusa.com
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Advanced Power
Electronics Corp.
APE8968MP-HF-3
Function Descriptions
Power-On-Reset
A Power-On-Reset (POR) circuit monitors both input voltages at VCNTL and VIN pins
to prevent incorrect logic controls. The POR function initiates a soft-start process after the
two supply voltages exceed their rising POR threshold voltages during powering on. The
POR function also pulls low the POK pin regardless of the output voltage when the VCNTL
voltage falls below its falling POR threshold.
Internal Soft-Start
An internal soft-start function controls the slew rate of the output voltage to limit the
current surge at start-up. The typical soft-start interval is about 2ms.
Current Limit
The APE8968-3 monitors the current via the output NMOSFET and limits the maximum
current to prevent damage to the load and the APE8968-3 during overload or short circuit
conditions.
Output Voltage Regulation
An error amplifier working with a temperature compensated 0.8V reference and an
output NMOSFET regulates output to the preset voltage. The error amplifier is designed
with high bandwidth and DC gain, providing very fast transient response and less load
regulation. It compares the reference with the feedback voltage and amplifies the difference
to drive the output NMOSFET which provides load current from VIN to VOUT.
Under Voltage Protection (UVP)
The APE8968-3 monitors the voltage on the FB pin after the soft-start process is finished.
Therefore the UVP is disabled during soft-start. When the voltage on FB pin falls below
the under-voltage threshold, the UVP circuit shuts off the output immediately. After a while,
the APE8968-3 starts a new soft-start to regulate output.
Thermal Shutdown
A thermal shutdown circuit limits the junction temperature of the APE8968-3. When the
junction temperature exceeds +150°C, a thermal sensor turns off the output NMOSFET,
allowing the device to cool down. The regulator regulates the output again through the
initiation of a new soft-start cycle after the junction temperature cools by 50°C, resulting
in pulsed output during continuous thermal overload conditions.
PCB Layout Consideration
It is necessary to solder the exposed pad to either Vin or the Gnd plane as a heat sink and
ensure it has enough pcb copper area to radiate the heat. Input capacitor, output capacitor,
voltage divider and bypass capacitors need to be
VIN
placed as close to the IC as possible to decouple
CIN
the high frequency ripple and noise.
VIN
The traces should be kept short and
wide to minimize the parasitic resistance
VOUT
and inductance, and the whole
VOUT
application circuit should be as
VOUT
COUT
VCNTL
close to the load as possible for
VCNTL
CCNTL
excellent load transient response.
C1
R1
FB
GND
R2
©2011 Advanced Power Electronics Corp.U SA
www.a-powerusa.com
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Advanced Power
Electronics Corp.
APE8968MP-HF-3
Typical Performance Characteristics
START UP WAVEFORM -1 VCNTL READY
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=100mA
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=1A
START UP WAVEFORM -2 VIN READY
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=100mA
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=2A
EN OFF → ON
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=100mA
©2011 Advanced Power Electronics Corp.U SA
www.a-powerusa.com
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=2A
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Advanced Power
Electronics Corp.
APE8968MP-HF-3
TYPICAL PERFORMANCE CHARACTERISTICS
LOAD TRANSIENT
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=0.1~3A
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=0.3~2.5A
SHORT CIRCUIT RELEASE
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=100mA
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=2A
THERMAL SHUT DOWN RELEASE
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=100mA
©2011 Advanced Power Electronics Corp. USA
www.a-powerusa.com
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=2A
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Advanced Power
Electronics Corp.
APE8968MP-HF-3
TYPICAL PERFORMANCE CHARACTERISTICS
POK VS. DISABLE
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=100mA
VCNTL=5V VIN=1.5V VOUT=1.2V IOUT=0A
DROPOUT VOLTAGE VS. OUTPUT CURRENT
VCNTL=5V, IOUT = 0mA to 3A
©2011 Advanced Power Electronics Corp. USA
www.a-powerusa.com
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Advanced Power
Electronics Corp.
APE8968MP-HF-3
Package Dimensions: ESOP-8
NOTES:Thermal Pad Dimemsions 2.25 ±0.1
Millimeters
8
7
6
SYMBOLS
MIN
NOM
MAX
A
5.80
6.00
6.20
B
4.80
4.90
5.00
C
3.80
3.90
4.00
D
0°
4°
8°
5
A
C
1
2
3
4
G
E
0.40
0.65
0.90
F
0.19
0.22
0.25
M
0.00
0.08
0.15
H
0.35
0.42
0.49
L
1.35
1.55
1.75
J
H
B
A2
0.375 REF.
K
45°
G
1.27 TYP.
L
I
J
1. All dimensions are in millimeters.
2. Dimensions do not include mold protrusions.
Marking Information
Product : APE8968
8968MP
YWWSSS
Package code : MP = RoHS-compliant halogen-free ESOP-8
Date/lot code (YWWSSS)
Y: Last digit of the year
W: Work week
SSS: Lot code sequence
©2011 Advanced Power Electronics Corp. USA
www.a-powerusa.com
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