Advanced Power

Electronics Corp. APE8981

3A ULTRA LOW DROPOUT LINEAR REGULATOR

FEATURES DESCRIPTION
Ultra Low Dropout 0.21V(typical) @ 2A Output The APE8981 series is a 3A ultra low dropout linear
Current for 1.2V Output Voltage regulator. This product is specifically designed to provide
well supply voltage for front-side-bus termination on
Low ESR Output Capacitor (Multi-layer Chip
motherboards and NB applications. The IC needs two
Capacitors (MLCC)) Applicable supply voltages, a control voltage for the circuitry and a
EN Pull-low for APE8981MP-A main supply voltage for power conversion, to reduce power
EN Pull-high for APE8981MP-B dissipation and provide extremely low dropout. The
Fast Transient Response APE8981 series integrates many functions. A Power-On-
Reset (POR) circuit monitors both supply voltages to
Adjustable Output Voltage by External Resistors
prevent wrong operations. A thermal shutdown and current
Power-On-Reset Monitoring on Both VCNTL limit functions protect the device against thermal and
and VIN Pins current over-loads. A POK indicates the output status with
Internal Soft-Start time delay which is set internally. It can control other
converter for power sequence.
Current-Limit and Thermal Shutdown Protection
The APE8981 series can be enabled by other power
Power-OK Output with a Delay Time system. Pulling and holding the EN pin below 0.4V shuts off
SO-8 with Exposed Pad Pb-Free & the output.
DFN 3x3-10L Package. The APE8981 series is available in DFN 3x3-10L &
ESOP-8 package which features small size as SO-8 and an
Halogen Free Product
Exposed Pad to reduce the junction-to-case resistance.

TYPICAL APPLICATION

POK
U1
R3
POK GND
10k
EN EN FB VOUT

VIN VIN VOUT

R1 CF Cout
VCNTL VCNTL NC 20k *option 10uF
C2
APE8981
C1 1 uF
R2
4 .7 uF
10k

Data and specifications subject to change without notice 1

201301046
 Advanced Power
Electronics Corp. APE8981
PACKAGE/ORDERING INFORMATION
( Top View ) ( Top View )
APE8981X-X POK 1 8 GND VOUT 1 10 VCNTL
VOUT 2 9 VIN
Package Type EN Function EN 2 7 FB
GND VOUT 3 GND 8 VIN
MP : ESOP-8 A : Internal Pull Low
GN3 : DFN 3x3-10L B : Internal Pull High VIN 3 6 VOUT FB 4 7 VIN
POK 5 6 EN
VCNTL 4 5 NC
DFN 3x3-10L
ESOP-8

ABSOLUTE MAXIMUM RATINGS (Note1)

CNTL Supply Voltage (VCNTL) --------------------------- -0.3V To 6.5V
Input Supply Voltage (VIN) ------------------------------- -0.3V To 6.5V
EN & FB Pin Voltage (VEN/VFB) ------------------------- -0.3V To VCNTL+0.3V
Power Good Voltage (VPOK) ---------------------------- -0.3V To 6.5V
Power Dissipation (PD) ---------------------------------- 2.5W
Storage Temperature Range (T ST) -------------------- -65°C To 150°C
Junction Temperature Range (T J) --------------------- -40°C To 150°C
Thermal Resistance Junction to Ambient (Rth ja)Note
ESOP-8 ------- 40°C/W
DFN 3x3-10L 62.5°C/W
Note
Thermal Resistance Junction to Case (Rth jc)
ESOP-8 ------- 15°C/W
DFN 3x3-10L 17°C/W

Note. mounted on a Demo board

RECOMMENDED OPERATING CONDITIONS

Operating Junction Temperature Range (T OJ) ----- -40°C To 125°C
Operating Ambient Temperature Range (T OA) ----- -40°C To 85°C
VCNTL Supply Voltage (VCNTL) ------------------------- 3V To 6V
Input Supply Voltage (VIN) ------------------------------- 1.1V To 5.5V
Output Voltage (VOUT)@VCNTL > VOUT + 2.5V ------- 0.8V To 2.8V
Output Cunrrent (IOUT) ------------------------------------ 0A To 3A

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ELECTRICAL SPECIFICATIONS
VCNTL= 5V, VIN=1.8V, VOUT=1.2V, TA=25oC unless otherwise specified
Parameter SYM TEST CONDITION MIN TYP MAX UNITS
VIN POR Threshold VIN 0.8 0.9 1 V
VIN POR Hysteresis VIN(hys) - 0.5 - V
VCNTL Nominal Supply Current ICNTL EN= VCNTL - 1.3 - mA
APE8981MP-A - - 1
VCNTL Shutdown Current ISD EN=0V uA
APE8981MP-B - 10 30
VCNTL=3 ~ 6V, IOUT=10mA,
Feedback Voltage VFB 0.784 0.8 0.816 V
VIN=VOUT+0.5~5.5V
Load Regulation IOUT=0A ~ 2A - 0.5 1 %
IOUT=100mA, VCNTL=VEN=5.0V,
On Resistance RDS(ON) - 105 150 mΩ
VOUT=1.2V
Dropout Voltage VDROP IOUT = 2A, VCNTL=5V, VOUT = 1.2V - 0.21 0.3 V
VOUT Pull Low Resistance EN=0V - 40 - Ω
Soft Start Time TSS - 0.2 - ms
VENH Enable 1.2 - -
EN Pin Logic High Threshold Voltage V
VENL Disable - - 0.6
EN=5V, APE8981MP-A - 10 20
EN Pin Pull-Up Current IEN uA
EN=GND, APE8981MP-B - 10 20
Current Limit ILIM VCNTL=5V, VIN=VOUT+1V 3.1 - - A
VIN - 65 -
Ripple Rejection PSRR F=120Hz, IOUT=100mA dB
VCNTL - 65 -
POK Threshold Voltage for Power OK VPOK VFB Rising 92% 94% 96% VFB
POK Threshold Voltage for Power Not OK VPNOK VFB Falling 83% 88% 91% VFB
POK Low Voltage POK sinks 5mA - - 0.1 V
POK Delay Time TDELAY 0.8 2 10 ms
(Note1) o
Thermal Shutdown Threshold TSD - 160 - C
Thermal Shutdown Hysteresis (Note1) - 40 - o
C
Note1: Guarantee by design, not production tested.

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Electronics Corp. APE8981
PIN DESCRIPTIONS
PIN SYMBOL PIN DESCRIPTION
POK Power OK Output Pin
APE8981MP-A: Internal pull low; HIGH for enable, LOW or floating for shutdown.
EN
APE8981MP-B: Internal pull high; HIGH or floating for enable, LOW for shutdown.
VIN Supply input for power conversion. The pin is monitored for Power-On Reset purpose.
Power input pin of the control circuitry. The pin is monitored for Power-On Reset
VCNTL
purpose.
NC No Connect
VOUT Output Voltage
FB Feedback Pin
GND GND Pin

BLOCK DIAGRAM
APE8981MP-A
N-MOSFET
VIN VOUT
Current
Limit Error
VCNTL Power- ON
Amp
Reset - +
Soft -Start
And
Control Logic Bandgap
EN Enable

10uA
Thermal
Shutdown FB
+

GND Delay POK

-

94%
V REF

POK

APE8981MP-B
N-MOSFET
VIN VOUT
Current
Limit Error
VCNTL Power- ON
Amp
Reset - +
Soft -Start
10uA
And
Control Logic Bandgap
EN Enable

Thermal
Shutdown FB
+

GND Delay POK

-

94%
V REF

POK

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Electronics Corp. APE8981
PIN DESCRIPTION
FB
Connecting this pin to an external resistor divider receives the feedback voltage of the
regulator. The output voltage set by the resistor divider is determined by:

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 with R1 in parallel to improve load transient
response. The R2 range in 1K~4.7KΩ for AL output capacitor and 30K~100KΩ for MLCC output
capacitor are recommended.

VIN
Main supply input pins for power conversions. The voltage at this pin is monitored for Power-
On Reset purpose.
VCNTL
Power input pin of the control circuitry. Connecting this pin to a +5V (recommended) supply
voltage provides the bias for the control circuitry. The voltage at this pin is monitored for Power-
On Reset purpose.
POK
Power-OK signal output pin. This pin is an open-drain output used to indicate status of
output voltage by sensing 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. For APE8981MP-B, this pin is internal pulled up
to VCNTL voltage, enabling the regulator. For APE8981MP-A, this pin is internal pulled down to
GND voltage, shutdown the regulator. The pull-high current is 10uA (typ.)

VOUT
Output of the regulator. Please connect Pin 6 using wide tracks. It is necessary to connect
an output capacitor with this pin for closed-loop compensation and improving transient responses.

FUNCTION DESCRIPTION
Power-On-Reset
A Power-On-Reset (POR) circuit monitors both input voltages at VCNTL and VIN pins to
prevent wrong 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 the output voltage when the VCNTL voltage falls below its falling
POR threshold.
Internal Soft-Start
An internal soft-start function controls rise rate of the output voltage to limit the current surge
at start-up. The typical soft-start interval is about 0.2ms.
Output Voltage Regulation
An error amplifier working with a temperature compensated 0.8V reference and an output
NMOS regulates output to the preset voltage. The error amplifier designed with high bandwidth
and DC gain provides very fast transient response and less load regulation. It compares the
reference with the feedback voltage and amplifies the difference to drive the output NMOS which
provides load current from VIN to VOUT.

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Electronics Corp. APE8981
FUNCTION DESCRIPTION
Current-Limit

The APE8981 monitors the current via the output NMOS and limits the maximum current to
prevent load and APE8981 from damages during overload or short circuit conditions.

Thermal Shutdown
A thermal shutdown circuit limits the junction temperature of APE8981. When the junction
temperature exceeds +160°C, a thermal sensor turns off the output NMOS, allowing the device to
cool down. The regulator regulates the output again through initiation of a new soft-start cycle
after the junction temperature cools by 40 ° C, resulting in a pulsed output during continuous
thermal overload conditions. The thermal shutdown designed.

APPLICATION INFORMATION
Capacitor Selection
Normally, use a MLCC capacitor on the input and output of the APE8981. Larger input
capacitor values provide better supply-noise rejection and transient response. A higher- value
output capacitor may be necessary if large, fast transients are anticipated and the device is
located several inches from the power source. The X5R and X7R type in MLCC is recommended.
For aluminum electrolytic capacitor application, 100uF in input capacitor and 220uF in output
capacitor (30m Ω < ESR < 200m Ω ) are recommended. Output capacitor of larger capacitance
can reduce noise and improve load transient response, stability, and PSRR.

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Electronics Corp. APE8981
TYPICAL PERFORMANCE CHARACTERISTICS
0.820 0.85

VCNTL=5
0.84
0.815

0.83
0.810
0.82

0.805
0.81
VO (V)

VO (V)
0.800 0.80

0.79
0.795

0.78
0.790

Io=0mA 0.77

0.785
Io=1A 0.76

0.780 0.75
3 3.4 3.8 4.2 4.6 5 0 0.5 1 1.5 2 2.5 3

V CNTL (V) I OUT (A)

Line Regulation Load Regulation

1000 1000

Vo=2.5V Vo=1.2V
900 900
Vo=1.8V Vo=1.05V
800 800
Vo=1.2V
700 Vo=1.05V 700
VDROP (mV)

VDROP (mV)

600 600

500 500

400 400

300 300

200 200

100 100

0 0
0 0.5 1 1.5 2 2.5 3 0 0.5 1 1.5 2 2.5 3

I OUT (A) I OUT (A)

Dropout Voltage at VCNTL=5V Dropout Voltage at VCNTL=3.3V

20.0

3.0
18.0

2.5 16.0

14.0
ICNTL-SD (uA)
ICNTL (mA)

2.0
12.0

10.0
1.5

8.0

1.0
6.0

4.0
0.5

2.0

0.0 0.0
-40 -20 0 20 40 60 80 -40 -20 0 20 40 60 80
T J (°C) T J (°C)

ICNTL vs. TJ ICNTL-SD (APE8981MP-B) vs. TJ

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Electronics Corp. APE8981
TYPICAL PERFORMANCE CHARACTERISTICS
0.90 2.0
VENH
0.88 1.8
VENL
0.86 1.6

0.84 1.4
VFB (V)

VEN (V)
0.82 1.2

0.80 1.0

0.78 0.8

0.76 0.6

0.74 0.4

0.72 0.2

0.70 0.0
-40 -20 0 20 40 60 80 -40 -20 0 20 40 60 80

T J (°C) T J (°C)

VFB vs. TJ VEN vs. TJ

VEN VIN
VOUT VOUT

POK POK
IOUT=3A IOUT=3A

EN on with POK Delay VIN Power –ON

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Electronics Corp. APE8981
MARKING INFORMATION
ESOP-8

Part Number
Package Code

8981MP-X EN Function
YWWSSS Date Code (YWWSSS)
Y：Last Digit Of The Year
WW：Week
SSS：Sequence

DFN 3x3-10L

Part Number
EN Function
8981-X
YWWS Date Code (YWWS)
Y：Last Digit Of The Year
WW：Week
S：Sequence