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AP7168
1.2A LOW DROPOUT REGULATOR WITH POK
Description
Pin Assignments
The AP7168 is a 1.2A, adjustable output voltage, ultra-low
dropout linear regulator. The device includes pass e lement,
error amplifier, band-gap reference, current limit and thermal
shutdown circuitry. The device is turned on when EN pin is
IN
1
set to logic high level. A Power-OK (POK) output is available
for power sequence control.
The characteristics of the low dropout voltage and low
quiescent current make it suitable for low to medium power
POK
NC
2
3
applications, for example, laptop computers, audio and video
applications, and battery powered devices. The typical
EN
4
quiescent current is approximately 125µA.
Built-in current-limit and thermal-shutdown functions prevent
IC from damage in fault conditions. The AP7168 is available
in SO-8EP package.
Features
NEW PRODUCT
• Wide input voltage range: 2.2V – 5.5V
• 230mV very low dropout at 500mA load
• 500mV very low dropout at 1A load
• Very low quiescent current (I
• Adjustable output voltage range: 0.8V to 5.0V
• Very fast transient response
• High PSRR
• Accurate voltage regulation
): 125µA typical
Q
Applications
• Servers and laptops
• Smart phone and PDA
• MP3/MP4
• Bluetooth headset
• Low and medium power applications
• FPGA and DSP core or I/O power
• Current limiting and short circuit protection
• Thermal shutdown protection
• Stable with any type output capacitor ≥ 4.7µF
• Ambient temperature range -40ºC to 85°C
• SO-8EP: Available in “Green” Molding Compound (No
Br, Sb)
• Lead Free Finish/ RoHS Compliant (Note 1)
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
( Top View )
SO-8EP
8
OUT
FB
7
NC
6
5
GND
Typical Application Circuit
AP7168
Document number: DS32019 Rev. 2 - 2
V
IN
1µF
100kOhm
Enable
IN
POK
EN
AP7168
OUT
R
FB
R
GND
V
OUT
1
2
10µF
⎛
⎜
REFOUT
⎜
⎝
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⎞
R
1
⎟
1VV
+=
⎟
R
2
⎠
September 2010
© Diodes Incorporated
Page 2
AP7168
1.2A LOW DROPOUT REGULATOR WITH POK
Pin Descriptions
Name Pin Number Description
IN 1 Voltage input pins, to be tied together externally. Bypass to ground through at least 1µF capacitor.
POK 2 Power-OK output, active-high open-drain.
EN 4 Enable input, active high.
GND 5 Ground.
FB 7 Output feedback.
OUT 8
NC 3, 6 No connection.
Functional Block Diagram
Voltage output pins, to be tied together externally. Bypass to ground through at least 4.7µF
ceramic capacitor.
NEW PRODUCT
Absolute Maximum Ratings
Symbol Parameter Ratings Unit
ESD HBM Human Body Model ESD Protection 4 KV
ESD MM Machine Model ESD Protection 300 V
VIN Input Voltage 7 V
OUT, FB, POK, EN Voltage VIN + 0.3 V
Continuous Load Current Internal Limited
TJ Operating Junction Temperature Range -40 ~ 150 °C
TST Storage Temperature Range -65 ~150 °C
P
Power Dissipation SO-8EP (Note 2, 4) 4.0 W
D
Notes: 2. Ratings apply to ambient temperature at 25°C
EN
POK
IN
Gate
Driver
Current Limit
and Thermal
Shutdown
0.8V
0.744V
OUT
FB
GND
Recommended Operating Conditions
Symbol Parameter Min Max Unit
V
IN
I
OUT
T
A
AP7168
Document number: DS32019 Rev. 2 - 2
Input voltage 2.2 5.5 V
Output Current 0 1.2 A
Operating Ambient Temperature -40 85
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°C
September 2010
© Diodes Incorporated
Page 3
Electrical Characteristics
= 25oC, V
(T
A
Symbol Parameter Test Conditions Min Typ. Max Unit
I
SHDN
V
Dropout
V
V
ΔV
OUT
ΔV
IN
ΔV
OUT
PSRR
NEW PRODUCT
I
I
SHORT
VOL
V
POK_TH_UP
V
POK_Hys
POK deglitch
I
POK_LK
T
T
Notes: 3. POK pin must be disconnected from IN pin.
layer and thermal vias to bottom layer ground plane.
= V
IN
I
Q
+1V, C
OUT
Input Quiescent Current I
= 1μF, C
IN
OUT
Input Shutdown Current VEN = 0V, I
Dropout Voltage
FB reference voltage 0.8 V
REF
I
FB
OUT
/ V
tST
/
FB leakage
Output Voltage Total Accuracy -3 3 %
Line Regulation
OUT
V
Load Regulation I
OUT
Start-up Time, from EN high to POK
high
Power Supply Rejection Ratio
LIMIT
V
IL
V
IH
I
EN
Current limit
Short-circuit Current V
EN Input Logic Low Voltage 0.4 V
EN Input Logic High Voltage 1.4 V
EN Input leakage V
POK output low voltage Force 2mA 100 200 mV
Output voltage (rising) POK threshold
Output voltage POK hysteresis 4% V
V
POK leakage current V
SHDN
HYS
θ
JA
4. Test condition for SO-8EP: Device mounted on 2" x 2" FR-4 substrate PCB, 2oz copper, with minimum recommended pad on top
Thermal shutdown threshold 145
Thermal shutdown hysteresis 25
Thermal Resistance Junction-to-
Ambient
= 1μF, V
1.2A LOW DROPOUT REGULATOR WITH POK
= 2V, unless otherwise stated)
EN
V
V
OUT
OUT
OUT
= 0
≥ 1.5V, I
≥ 1.5V, I
= 0 (Note 3) -1 0.1 1 µA
OUT
= 0.5A
OUT
= 1A
OUT
⎯
⎯
VIN = V
I
OUT
OUT
V
EN
V
IN
1kHz, V
I
OUT
V
OUT
IN
EN
FB (or OUT for fixed version)
rising
IN
POK
+1V to 5.5V,
OUT
= 1mA
from 1mA to 1A -1.5 1.5 %
= 0V to 2.0V, I
= 100mA,
OUT
= 3.3V
= 3.3V, V
IN
= 1.2V,
OUT
= 100mA
= 1.8V, R
= 3.3V, V
= 0V or 5.5V
= 0.5Ω
OUT
< 0.2V 750 mA
OUT
1.2 1.6 A
⎯
87% 92% 97% V
= 3.3V, V
= 5.5V
= 1.2 V 160 µs
OUT
⎯
SOP-8L-EP (Note 4) 27
125 180 µA
230 mV
500 800 mV
0.01 1 µA
0.02 %/V
190 µs
60 dB
0.01 1 µA
0.01 1 µA
AP7168
ref
ref
°C
°C
o
C/W
AP7168
Document number: DS32019 Rev. 2 - 2
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© Diodes Incorporated
Page 4
Typical Performance Characteristics
AP7168
1.2A LOW DROPOUT REGULATOR WITH POK
NEW PRODUCT
Output Voltage vs. Temperature
3.40
3.35
3.30
3.25
Output Voltage (V)
3.20
VOUT = 3.3V
-50 -25 0 25 50 75 100 125
Temperature (0C)
Quiescent Current vs. Input Voltage
=3.3V
V
OUT
170
A)
155
μ
140
125
110
95
Quiescent Current (
80
4.0 4.3 4.6 4.9 5.2 5.5
Input Voltage (V)
Iout=0mA
Iout=500mA
Output Voltage vs. Temperature
1.30
1.25
1.20
1.15
VOUT = 1.2V
Output Voltage (V)
1.10
-50-25 0 255075100125
Temperature (0C)
Quiescent Current vs. I
V
=1.8V
170
A)
160
μ
150
140
130
120
110
Quiescent Current (
100
OUT
0.0 0. 2 0.4 0.6 0.8 1.0 1. 2
I
(A)
OUT
OUT
VIN=2.5V
VIN=3.3V
Quiescent Current vs. Temperatu re
170
A)
π
155
140
125
110
95
Quiescent Current (
80
-50.0 -25.0 0.0 25.0 50. 0 75.0 100.0 125.0
Temperature (0C)
AP7168
Document number: DS32019 Rev. 2 - 2
Reference Voltage vs. Temperature
0.810
0.805
0.800
VIN=2.2V, Vout=1.0V
VIN=3.3V, Vout=1.8V
VIN=5.0V, Vout=3.3V
0.795
Reference Voltage (V)
0.790
-50-25 0 255075100125
Vin=2.2V
Vin=3.3V
Vin=5.5V
Temperature (0C)
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© Diodes Incorporated
Page 5
1.2A LOW DROPOUT REGULATOR WITH POK
Typical Performance Characteristics (Continued)
AP7168
NEW PRODUCT
Line Regulati on
V
=1.8V, I
OUT
0.10
0.05
(%/V)
OUT
0.00
-0.05
OUT
=1mA
Change in V
-0.10
3.0 3.5 4.0 4. 5 5.0 5.5
VIN (V)
Short Circuit Current vs. Input Voltage
V
=1.2V
OUT
0.77
0.76
0.75
0.74
0.73
0.72
0.71
0.70
Short Circuit Current (A)
0.69
2.2 2.4 2.6 2.8 3 3.2 3.4
Input Voltage (V)
25°C
85°C
-40°C
Load Regulation
V
=2.2V, V
IN
0.5
0.4
0.3
(%)
0.2
OUT
0.1
0.0
-0.1
-0.2
-0.3
Change in V
-0.4
-0.5
0.0 0.4 0.8 1.2
25°C
85°C
-40°C
OUT
=1.2V,
I
OUT
(A)
Short Circuit Current vs. Temperature
V
=1.2V
OUT
0.80
0.75
0.70
0.65
Short Circuit Current (A)
0.60
-50 -25 0 25 50 75
Temperature (oC)
Dropout Voltage vs. I
V
=3.3V
OUT
700
600
500
400
300
200
100
Dropout Voltage (mV)
0
0 0.2 0.4 0.6 0.8 1 1.2
AP7168
Document number: DS32019 Rev. 2 - 2
I
OUT
(A)
OUT
25°C
85°C
-40°C
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PSRR
-40
-45
-50
-55
-60
-65
PS RR (dB)
-70
-75
-80
100 1000 10000 100000
Frequency (Hz)
September 2010
© Diodes Incorporated
Page 6
1.2A LOW DROPOUT REGULATOR WITH POK
Typical Performance Characteristics (Continued)
Line Transient Response
V
=3V to 5.5V
IN
C
=10uF
OUT
Line Transient Response
V
=5.5V to 3V
IN
C
=10uF
OUT
AP7168
VIN
2V/div
V
OUT
50mV/div
Time (5ms/div)
Output Load Transient Response (V
NEW PRODUCT
V
OUT
100mV/div
1.2A
I
OU
500mA/div
C
=470uF (electrolytic)
OUT
C
=10uF (Ceramic)
OUT
C
=1uF (Ceramic)
OUT
1A/us
OUT
=1.8V)
VIN
2V/div
V
OUT
50mV/div
Time (500us/div)
Output Load Transient Response (V
V
OUT
100mV/div
1.2A
I
OU
500mA/div
C
=470uF (electrolytic)
OUT
C
=10uF (Ceramic)
OUT
C
=1uF (Ceramic)
OUT
1A/us
OUT
=3.3V)
50mA
Time (100us/div)
Start-up Time (V
VEN
2V/div
V
OUT
1V/div
V
POK
2V/div
C
OUT
OUT
Time (50us/div)
AP7168
Document number: DS32019 Rev. 2 - 2
=1.2V, I
=10uF
OUT
=0.1A)
VEN
2V/div
V
OUT
1V/div
V
POK
2V/div
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50mA
Time (100us/div)
Start-up Time (V
C
OUT
Time (50us/div)
OUT
=10uF
=1.2V, I
=1.2A)
OUT
September 2010
© Diodes Incorporated
Page 7
Typical Performance Characteristics (Continued)
Current Limit vs. Temperature
1.8
1.7
1.6
1.5
Current Limit (A)
1.4
-50 -25 0 25 50 75 100
NEW PRODUCT
Application Note
AP7168
1.2A LOW DROPOUT REGULATOR WITH POK
VIN =2.8V,Vout=1.8V
VIN =3.3V,Vout=1.8V
Temperature (oC)
Input Capacitor
A 1μF ceramic capacitor is recommended to connect
between IN and GND pins to decouple input power supply
glitch and noise. The amount of the capacitance may be
increased without limit. A lower ESR (Equivalent Series
Resistance) capacitor allows the use of less capacitance,
while higher ESR type requires more capacitance. This
input capacitor should be located as close as possible to
the device to assure input stability and less noise. For
PCB layout, a wide copper trace is required for both IN
and GND.
Output Capacitor
The output capacitor is required to stabilize and help the
transient response of the LDO. The AP7168 is designed to
have excellent transient response for most applications
with a small amount of output capacitance. The AP7168 is
stable for all available types and values of output
capacitors ≥ 4.7μF . The device is also stable with multiple
capacitors in parallel, which can be of any type of value.
Additional capacitance helps to reduce undershoot and
overshoot during transient. This capacitor should be
placed as close as possible to OUT and GND pins for
optimum performance.
Adjustable Operation
The AP7168 provides output voltage from 0.8V to 5.0V
through external resistor divider as shown below.
V
IN
C
IN
The output voltage is calculated by:
Where V
Rearranging the equation will give the following equation
to find the approximate resistor divider values:
To maintain the stability of the internal reference voltage,
R
needs to be kept smaller than 250kΩ.
2
=0.8V (the internal reference voltage)
REF
100kOhm
Enable
IN
POK
EN
AP7168
RR
21
OUT
FB
GND
⎛
⎜
1VV
V
V
⎜
⎝
OUT
REF
+=
REFOUT
⎛
⎜
⎜
⎝
R
1
R
2
R
R
−= 1
V
OUT
C
OUT
⎞
1
⎟
⎟
2
⎠
⎞
⎟
⎟
⎠
AP7168
Document number: DS32019 Rev. 2 - 2
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Page 8
=
−
Application Note (Continued)
AP7168
1.2A LOW DROPOUT REGULATOR WITH POK
No Load Stability
Other than external resistor divider, no minimum load is
required to keep the device stable. The device will remain
stable and regulated in no load condition.
ENABLE/SHUTDOWN Operation
The AP7168 is turned on by setting the EN pin high, and is
turned off by pulling it low. If this feature is not used, the
EN pin should be tied to IN pin to keep the regulator output
on at all time. To ensure proper operation, the signal
source used to drive the EN pin must be able to swing
above and below the specified turn-on/off voltage
thresholds listed in the Electrical Characteristics section
under V
and VIH.
IL
POWER-OK
The Power-Ok (POK) pin is an active high open-drain
output. It can be connected to any 5.5V or lower rail
NEW PRODUCT
through an external pull-up resistor. The recommended
sink current of POK pin is up to 4mA, so the pull-up
resistor for POK should be in the range of 10kΩ to 1MΩ. If
output voltage monitoring is not needed, the POK pin can
be left floating.
Current Limit Protection
When output current at OUT pin is higher than current limit
threshold, the current limit protection will be triggered and
clamp the output current to approximately 1.6A (1.2A min)
to prevent over-current and to protect the regulator from
damage due to overheating.
Short Circuit Protection
When OUT pin is short-circuited to GND or OUT pin
voltage is less than 200mV, short circuit protection will be
triggered and clamp the output current to approximately
750mA. This feature protects the regulator from overcurrent and damage due to overheating.
Low Quiescent Current
The AP7168, consuming only around 150µA for all input
range and output loading, provides great power saving in
portable and low power applications.
Wide Output Range
The AP7168, with a wide output range of 0.8V to 5.0V,
provides a versatile solution for many portable and low
power applications.
Thermal Shutdown Protection
Thermal protection disables the output when the junction
temperature rises to approximately +145°C, allowing the
device to cool down. When the junction temperature
reduces to approximately +120°C the output circuitry is
enabled again. Depending on power dissipation, thermal
resistance, and ambient temperature, the thermal
protection circuit may cycle on and off. This cycling limits
the heat dissipation of the regulator, protecting it from
damage due to overheating.
Power Dissipation
The device power dissipation and proper sizing of the
thermal plane that is connected to the thermal pad is
critical to avoid thermal shutdown and ensuring reliable
operation. Power dissipation of the device depends on
input voltage and load conditions and can be calculated
by:
xI)VV(P −
OUTOUTIND
The AP7168 is available in the SO-8EP packages, both
with exposed pad, which is the primary conduction path fo r
heat to the printed circuit board (PCB). The pad can be
connected to ground or be left floating; however, to ensure
the device will not overheat, it should be attached to an
appropriate amount of copper PCB area.
However, the maximum power dissipation that can be
handled by the device depends on the maximum junction
to ambient thermal resistance, maximum ambient
temperature, and maximum device junction temperature,
which can be approximated by the equation below:
)T(max@P
°+
=
AD
R
JA
θ
)TC150(
A
AP7168
Document number: DS32019 Rev. 2 - 2
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© Diodes Incorporated
Page 9
Ordering Information
AP7168
1.2A LOW DROPOUT REGULATOR WITH POK
AP7168-SP G -13
Package Green
SP :
SO-8EP
G : Gr een
13 : T ape & Reel
Device
AP7168-SPG-13 SP SO-8EP 2500/Tape & Reel -13
Notes: 5. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf.
Package
Code
Packaging
(Note 5)
Quantity Part Number Suffix
13” Tape and Reel
Marking Information
NEW PRODUCT
SO-8EP
( Top View )
X
5
G : Green
YY
: Year : 08, 09,10~
WW
: Week : 01~52; 52
E
represents 52 and 53 week
X
: Internal Code
Logo
Part No.
8
AP7168
WW X
YY
SOP-8L-EP
41
Packing
AP7168
Document number: DS32019 Rev. 2 - 2
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1.2A LOW DROPOUT REGULATOR WITH POK
Package Outline Dimensions
Package Type: SO-8EP
AP7168
Detail "A"
7°~9°
45°
3.85/3.95
5.90/6.10
1.30/1.50
1.75max.
Exposed pad
0.35max.
0.15/0.25
0/0.13
Detail "A"
7°~9°
1
1.27typ
1
8x-0.60
0.3/0.5
4.85/4.95
NEW PRODUCT
5.4
6x-1.27
8x-1.55
Land Pattem Recommendation
(Unit:mm)
Notes: 6. All dimensions are in millimeters. Angles are in degrees.
7. Coplanarity applies to the exposed heat sink slug as well as the terminals.
3.70/4.10
0.62/0.82
3.3Ref.
Bottom View
0.254
Gauge Plane
Seating Plane
Exposed pad
2.4Ref.
1
AP7168
Document number: DS32019 Rev. 2 - 2
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© Diodes Incorporated
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AP7168
1.2A LOW DROPOUT REGULATOR WITH POK
NEW PRODUCT
IMPORTANT NOTICE
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS
DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other
changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability
arising out of the application or use of this document or any product described herein; neither does Diodes In corporated convey any
license under its patent or trademark rights, nor the rights of others. Any Customer or user of this documen t or products described
herein in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies
whose products are represented on Diodes Incorporated website, harmless against all damages.
Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized
sales channel.
Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall
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arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
Products described herein may be covered by one or more United States, international or foreign p atents pending. Product names
and markings noted herein may also be covered by one or more United States, international or foreign trademarks.
LIFE SUPPORT
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without
the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided
in the labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is an y component in a life support device or system whose failure to perform can be reasonabl y expected
to cause the failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support dev ices or
systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements
concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems,
notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further,
Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes
Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2010, Diodes Incorporated
www.diodes.com
AP7168
Document number: DS32019 Rev. 2 - 2
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