Advanced Power
Electronics Corp.
3A ULTRA LOW DROPOUT LINEAR REGULATOR
FEATURES DESCRIPTION
Ultra Low Dropout 0.23V(typical) @ 2A Output
Current for 1.2V Output Voltage
Low ESR Output Capacitor (Multi-layer Chip
Capacitors (MLCC)) Applicable
EN Pull-low for APE8903BMP-A
EN Pull-high for APE8903BMP-B
Fast Transient Response
Adjustable Output Voltage by 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
SO-8 with Exposed Pad Pb-Free Package.
1. Using an Output Capacitor with ESR≧20mΩ
Data and specifications subject to change without notice
201012132
APE8903B
TYPICAL APPLICATION
1
The APE8903B series is a 3A ultra low dropout linear
regulator. This product is specifically designed to provide
well supply voltage 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 APE8903B series
integrates many functions. A Power-On-Reset (POR) circuit
monitors both supply voltages to prevent wrong operations.
A
thermal shutdown and current limit functions protect the
device against thermal and current over-loads. A POK
indicates the output status with time delay which is set
internally. It can control other converter for power sequence.
The APE8903B series can be enabled by other power
system. Pulling and holding the EN pin below 0.6V shuts off
the output.
The APE8903B series is available in ESOP-8 package
which features small size as SO-8 and an Exposed Pad to
reduce the junction-to-case resistance, being applicable in
2~3W applications.
C1
1uF
R1
1K
Vout=1.2V/2A
VIN=1.8V
R3
VCNTL=5V
C4
220uF
C5
0.1 uF
U1
APE8903B
VCNTL
FB
VOUT
GND
NC
EN
POK
VIN
C2
100uF
C3
0.1uF
C6
12~48nF
R2
2K
OFF
ON
10K
option
Advanced Power
Electronics Corp. APE8903B
2. Using an MLCC as the Output Capacitor
ABSOLUTE MAXIMUM RATINGS (Note1)
CNTL Supply Voltage (VCNTL) --------------------------
-
-0.3V to 6.5V
Input Supply Voltage (VIN) -------------------------------
-
-0.3V to 6.5V
Output Voltage (VOUT) -------------------------------------
-
0.8V to 6V
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 (TST) --------------------
-
-65°C to 150°C
Junction Temperature Range (TJ) --------------------- -40°C to 150°C
Thermal Resistance Junction to Ambient (Rthja)Note 40°C/W
Thermal Resistance Junction to Case (Rthjc) ------
15°C/W
Note. Rthja is measured with the PCB copper area (need connect to Expose-Pad) of approximately 1.5 in2 (Multi-layer)
RECOMMENDED OPERATING CONDITIONS
Operating Junction Temperature Range (TOJ) -----
-
-40°C To 125°C
Operating Ambient Temperature Range (TOA) -----
-
-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=5V --------------------
-
0.8V To 2.8V
Output Cunrrent (IOUT) ------------------------------------
-
0A To 3A
PACKAGE/ORDERING INFORMATION
2
TYPICAL APPLICATION
(Top View)
1
2
3
4
8
7
6
5NC
VOUT
ESOP-8
GND
FBEN
POK
VIN
VCNTL
GND
Package Type
MP : ESOP-8
APE8903BX-X
EN Function
A : Pull Low
B : Pull High
VIN=1.8V
R3
10K
VOUT=1.2V/2A
VFB = 0.8V
U2
APE8903B
VCNTL
FB
VOUT
GND
NC
EN
POK
VIN
C6
56pF
C5
10uF
C1
1uF
C3
4.7uF
VOUT=VFB x (1+R1/R2)
VCNTL=5V
R2
78K
R1
39K
OFF
ON
option
Advanced Power
Electronics Corp. APE8903B
ELECTRICAL SPECIFICATIONS
VCNTL= 5V, VIN=1.8V, VOUT=1.2V, TA=25oC 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
VCNTL Nominal Supply Current ICNTL EN= VCNTL 0.4 1 1.5 mA
--1uA
-1030uA
VCNTL=3 ~ 6V, IOUT=10mA,
VIN=VOUT+0.5~5.5V
Load Regulation IOUT=0A ~ 2A - 0.2 1 %
IOUT=100mA, VCNTL=VEN=5.0V,
VOUT=1.2V
Dropout Voltage VDROP IOUT = 2A, VCNTL=5V, VOUT = 1.2V - 0.23 0.3 V
VOUT Pull Low Resistance EN=0V - 90 - Ω
Soft Start Time TSS -2-ms
VENH Enable 1.2 - -
VENL Disable - - 0.6
EN Hysteresis -40-mV
EN=5V, APE8903BMP-A - 10 20
EN=GND, APE8903BMP-B - 10 20
Current Limit ILIM VCNTL=5V, VIN=VOUT+1V 3.1 - - A
-65-
-65-
VCNTL=5V, COUT=10uF,
EN startup, IOUT=2A
Under-Voltage Threshold 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 78% 81% 84% VFB
POK Low Voltage POK sinks 5mA - 0.25 0.4 V
POK Delay Time TDELAY 0.8 2 10 ms
Thermal Shutdown Temp TSD - 160 - oC
Thermal Shutdown Hysteresis - 40 - oC
Inrush current
Feedback Voltage VFB
Ripple Rejection PSRR
EN Pin Pull-Up Current IEN
F=120Hz, IOUT=100mA
- 0.5 -
uA
EN Pin Logic High Threshold
Voltage
On Resistance RDS(ON)
VCNTL Shuntdown Current ISD
0.784
- 115
0.8
3
V
0.816 V
150 mΩ
dB
A
V
IN
VCNTL
EN = 0V
A
PE8903B-A
A
PE8903B-B
Advanced Power
Electronics Corp. APE8903B
PIN DESCRIPTIONS
PIN SYMBOL PIN DESCRIPTION
POK Power OK Output Pin
Internal Pull High (APE8903BMP-B) or Pull Low (APE8903BMP-A)
EN=High or Floating → Enable
EN=Low → Shutdown Mode
VIN Input Voltage.
VCNTL CNTL Pin Input Voltage
NC No Connect
VOUT Output Voltage
FB Feedback Pin
GND GND Pin
BLOCK DIAGRAM
APE8903BMP-A
APE8903BMP-B
4
EN
-+
VIN VOUT
GND
Error
Amp
EN
VCNTL
Soft-Start
And
Control Logic
Power -ON
Reset
Current
Limit
Thermal
Shutdown
Bandgap
FB
-+
POK
Delay
-+UV
0.4V
92%
VREF
N-MOSFET
10uA
Enable
-+
VIN VOUT
GND
Error
Amp
EN
VCNTL
Soft-Start
And
Control Logic
Power -ON
Reset
Current
Limit
Thermal
Shutdown
Bandgap
FB
-+
POK
Delay
POK
-+UV
0.4V
92%
VREF
N-MOSFET
10uA
Enable
Advanced Power
Electronics Corp. APE8903B
PIN DESCRIPTION
FB
VIN
VCNTL
POK
EN
VOUT
FUNCTION DESCRIPTION
Power-On-Reset
Internal Soft-Start
Output Voltage Regulation
Current-Limit
5
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:
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.
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 2ms.
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.
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.
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.
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.
Enable control pin. Pulling and holding this pin below 0.6V shuts down the output. When re-
enabled, the IC undergoes a new soft-start cycle. For APE8903BMP-B, this pin is internal pulled up
to VCNTL voltage, enabling the regulator. For APE8903BMP-A, this pin is internal pulled down to
GND voltage, shutdown the regulator. The pull-high or pull-low current is 10uA (typ.)
Regulator output pin. 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.
The APE8903B monitors the current via the output NMOS and limits the maximum current to
prevent load and APE8903B from damages during overload or short circuit conditions.
Main supply input pins for power conversions. The voltage at this pin is monitored for Power-
On Reset purpose.
Advanced Power
Electronics Corp. APE8903B
FUNCTION DESCRIPTION
Under-Voltage Protection (UVP)
Thermal Shutdown
APPLICATION INFORMATION
Capacitor Selection
6
The APE8903B monitors the voltage on FB pin after soft-start process is finished. Therefore
the UVP is disabling 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 APE8903B starts a
new soft-start to regulate output.
A thermal shutdown circuit limits the junction temperature of APE8903B. 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.
Normally, use a MLCC capacitor on the input and output of the APE8903B. 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
(30mΩ < ESR < 200mΩ) are recommended. Output capacitor of larger capacitance can reduce
noise and improve load transient response, stability, and PSRR.
Advanced Power
Electronics Corp. APE8903B
TYPICAL PERFORMANCE CHARACTERISTICS
7
0.780
0.785
0.790
0.795
0.800
0.805
0.810
0.815
0.820
3 3.5 4 4.5 5 5.5 6
V
CNTL
(V)
V
FB
(V)
Line Regulation
V
IN
=1.8V, V
OUT
=1.2V
I
OUT
=10mA
0.780
0.785
0.790
0.795
0.800
0.805
0.810
0.815
0.820
00.511.522.53
IOUT (A)
V
FB
(V)
Load Regulation
V
CNT L
=5V, V
IN
=1.8V,
V
OUT
=1.2V
0
100
200
300
400
500
600
700
800
00.511.522.53
IOUT (A)
Dropout Voltage (mV)
Dropout Voltage (V
CNTL
=3.3V)
V
OUT
=1.2V
V
OUT
=1.5V
0
100
200
300
400
500
600
00.511.522.53
IOUT (A)
Dropout Voltage (mV)
Dropout Voltage (V
CNTL
=5V)
V
OUT
=1.2V
V
OUT
=2.5V
V
OUT
=1.8V
0.780
0.785
0.790
0.795
0.800
0.805
0.810
0.815
0.820
-40℃ -20℃ 0℃ 25℃ 50℃ 75℃ 100℃ 125℃
Temperature (℃)
V
FB
(V)
Temperature VS V
FB
V
CNTL
=5V, V
IN
=1.8V,
V
OUT
=1.2V, I
OUT
=10mA
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
-40℃ -20℃ 0℃ 25℃ 50℃ 75℃ 100℃ 125℃
Tem
p
erature
(
℃
)
I
CNTL
(mA)
Temperature VS Quiescent Current
V
CNTL
=5V, V
IN
=1.8V,
V
OUT
=1.2V, I
OUT
=0A
Advanced Power
Electronics Corp. APE8903B
TYPICAL PERFORMANCE CHARACTERISTICS
Line Transient Line Transient
8
Load Transient VCNTL Power –ON
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
-40℃ -20℃ 0℃ 25℃ 50℃ 75℃ 100℃ 125℃
Temperature (℃)
Enable Threshold Voltage (V)
Temperature VS Enable Threshold Voltage
V
CNTL
=5V
V
ENH
V
ENL
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
-40℃ -20℃ 0℃ 25℃ 50℃ 75℃ 100℃ 125℃
Temperature (℃)
V
CNTL
POR Threshold Voltage (V)
Temperature VS V
CNTL
POR Threshold
Rising
Falling
Advanced Power
Electronics Corp. APE8903B
TYPICAL PERFORMANCE CHARACTERISTICS
9
VIN Power –ON Enable –ON with POK Delay
Advanced Power
Electronics Corp. APE8903B
MARKING INFORMATION
ESOP-8
10
8903BMP-X
YWWSSS
Part Number
Date Code (YWWSSS)
Y：Last Digit Of The Year
WW：Week
SSS：Sequence
Package Code
EN Function