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AAT3216
Datasheet (Analogic Tech)
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Datasheet AAT3216 Datasheet (Analogic Tech)

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Page 1
SmartSwitch
™
AAT3216
150mA MicroPower™ LDO with PowerOK
Preliminary Information
3216.2004.01.0.94 1
General Description
The AAT3216 MicroPower™ Low Dropout Linear Regulator is ideally suited for portable applications where low noise, extended battery life and small size are critical. The AAT3216 has been specifi­cally designed for low output noise performance, fast transient response and high power supply rejection ratio (PSRR), making it ideal for powering sensitive RF circuits.
Other features include low quiescent current, typi­cally 70µA, and low dropout voltage which is typi­cally less than 200mV at full output current. The device is output short circuit protected and has a thermal shutdown circuit for additional protection under extreme conditions.
The AAT3216 also features a low-power shutdown mode for extended battery life. A Power-OK open­drain output signals when V
OUT
is in regulation.
The AAT3216 is available in a space saving 5-pin SOT23 or 8-pin SC70-JW package in 12 factory programmed voltages of 1.2V, 1.5V, 1.8V, 2.0V,
2.3V, 2.5V, 2.7V, 2.8V, 2.85, 3.0V, 3.3V, or 3.5V.
Features
• Low Dropout - 200mV at 150mA
• Guaranteed 150mA Output
• High accuracy ±1.5%
• 70µA Quiescent Current
• High Power Supply Ripple Rejection
• Low self noise
• PowerOK (POK) Output
• Fast line and load transient response
• Short circuit protection
• Over-Temperature protection
• Uses Low ESR ceramic capacitors
• Shutdown mode for longer battery life
• Low temperature coefficient
• 12 Factory programmed output voltages
• SOT23 5-pin or SC70-JW 8-pin package
Applications
• Cellular Phones
• Notebook Computers
• Desktop Computers
• Portable Communication Devices
• Personal Portable Electronics
• Digital Cameras
Typical Application
PowerLinear
™
查询AAT3216供应商查询AAT3216供应商
V
IN
ON/OFF
1µF
GND GND
IN
EN
AAT3216
GND
OUT
100k
POK
2.2µF
V
OUT
POK
Page 2
AAT3216
150mA MicroPower™ LDO with PowerOK
2 3216.2004.01.0.94
Pin Descriptions
Pin Configuration
SOT23-5 SC70JW-8
(Top View) (Top View)
Pin #
Symbol Function
SOT23-5 SC70JW-8
1 5, 6 IN Input voltage pin - should be decoupled with 1µF or greater
capacitor.
2 8 GND Ground connection pin
3 7 EN Enable pin - this pin should not be left floating. When pulled low
the PMOS pass transistor turns off and all internal circuitry enters low-power mode, consuming less than 1µA.
4 1 POK Power-OK Output. This open-drain output is low when OUT is out
of regulation. Connect a pull up resistor from POK to OUT or IN.
5 2, 3, 4 OUT Output pin - should be decoupled with 2.2µF ceramic capacitor.
IN
GND
EN
1 2
1
OUT
5 2 3
POK
4
POK
OUT OUT OUT
1
2
3
4
8
7
6
5
GND EN IN
IN
Page 3
Absolute Maximum Ratings (T
A
=25°C unless otherwise noted)
Note: Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at con­ditions other than the operating conditions specified is not implied. Only one Absolute Maximum rating should be applied at any one time.
Thermal Information
Note 1: Mounted on a demo board.
Recommended Operating Conditions
Note 2: To calculate minimum input voltage, use the following equation: V
IN(MIN)
= V
OUT(MAX)
+ V
DO(MAX)
as long as V
IN
≥ 2.5V.
Symbol Description Rating Units
V
IN
Input Voltage
2
(V
OUT
+ VDO) to 5.5 V
T Ambient Temperature Range -40 to +85 °C
Symbol Description Rating Units
Θ
JA
Maximum Thermal Resistance1(SOT23-5, SC70JW-8) 190 °C/W
P
D
Maximum Power Dissipation1(SOT23-5, SC70JW-8) 526 mW
Symbol Description Value Units
V
IN,
POK Input Voltage, POK 6 V
I
OUT
DC Output Current PD/(VIN-VO)mA
T
J
Operating Junction Temperature Range -40 to 150 °C
AAT3216
150mA MicroPower™ LDO with PowerOK
3216.2004.01.0.94 3
Page 4
Electrical Characteristics (V
IN=VOUT(NOM)
+1V for V
OUT
options greater than 1.5V. VIN= 2.5 for
V
OUT
≤1.5V. I
OUT
=1mA, C
OUT
=2.2µF, CIN=1µf, TA= -40 to 85°C unless otherwise noted. Typical values are at
T
A
=25°C)
Note 1: VDOis defined as VIN- V
OUT
when V
OUT
is 98% of nominal.
Note 2: For V
OUT
< 2.3V, VDO= 2.5V - V
OUT
.
Note 3: C
IN
= 10µF
Symbol Description Conditions Min Typ Max Units
V
OUT
Output Voltage Tolerance I
OUT
= 1mA to 150mA
T
A
=25°C -1.5 1.5 %
TA=-40 to 85°C -2.5 2.5 %
I
OUT
Output Current V
OUT
> 1.2V 150 mA
V
DO
Dropout Voltage
1, 2
I
OUT
= 150mA 200 300 mV
I
SC
Short Circuit Current V
OUT
< 0.4V 600 mA
I
Q
Ground Current VIN= 5V, No load, EN = V
IN
70 125 µA
I
SD
Shutdown Current VIN= 5V, EN = 0V 1 µA
∆V
OUT/VOUT
*∆V
IN
Line Regulation
3
VIN= V
OUT
+ 1 to 5.0V 0.09 %/V
∆V
OUT
(line) Dynamic Line Regulation VIN=V
OUT
+1V to V
OUT
+2V, I
OUT
=150mA, 5 mV
TR/TF=2µs
∆V
OUT
(load) Dynamic Load Regulation I
OUT
= 1mA to 150mA, TR<5µs 30 mV
V
EN(L)
Enable Threshold Low 0.6 V
V
EN(H)
Enable Threshold High 1.5 V
I
EN
Leakage Current on Enable Pin VEN= 5V 1 µA
V
POK
POK Trip Threshold V
OUT
rising, TA= 25°C 90 94 98 % of V
OUT
V
POKHYS
POK Hysteresis 1 % of V
OUT
V
POK(OL)
POK Output Voltage Low I
SINK
= 1mA 0.4 V
I
POK
POK Output Leakage Current V
POK
< 5.5V, V
OUT
in regulation 1 µA
1 kHz 65
PSRR Power Supply Rejection Ratio I
OUT
=10mA 10kHz 45 dB
1MHz 42
T
SD
Over Temp Shutdown Threshold 145 °C
T
HYS
Over Temp Shutdown Hysteresis 12 °C
e
N
Output Noise Noise Power BW = 300Hz-50kHz 250 µVrms/rtHz
TC Output Voltage Temp. Coeff. 22 ppm/°C
AAT3216
150mA MicroPower™ LDO with PowerOK
4 3216.2004.01.0.94
Page 5
AAT3216
150mA MicroPower™ LDO with PowerOK
3216.2004.01.0.94 5
Typical Characteristics
(Unless otherwise noted, VIN= 5V, TA= 25°C)
Output Voltage (V)
)
)
(°C)
Dropout Voltage vs. Temperature
260 240 220
IL = 150mA
200 180 160 140 120 100
80 60 40 20
Dropout Voltage (mV)
0
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120
IL = 100mA
IL = 50mA
Temperature
Dropout Voltage vs. Output Current
300
250
200
150
100
50
Dropout Voltage (mV)
0
0 25 50 75 100 125 150
85°C
25°C
-40°C
Output Current (mA
Dropout Characteristics
3.20
3.00
I
= 0mA
OUT
2.80
(V)
2.60
OUT
V
2.40
2.20
2.00
I
OUT
2.70 2.80 2.90 3.00 3.10 3.20
I
= 100mA
OUT
= 150mA
I
OUT
= 50mA
I
= 10mA
OUT
V
(V)
IN
Ground Current vs. Input Voltage
90.00
80.00
70.00
60.00
50.00
(µA)
40.00
GND
I
I
=0mA
OUT
30.00
20.00
10.00
0.00 2 2.5 3 3.5 4 4.5 5
I
OUT
=10mA
I
OUT
I
=150mA
OUT
=50mA
V
(V
Quiescent Current vs. Temperature
100
90
80
70
60
50
40
30
20
10
Quiescent Current (µA)
0
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120
Temperature (°C)
Output Voltage vs. Temperature
1.203
1.202
1.201
1.200
1.199
1.198
1.197
1.196
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Temperature (°C)
Page 6
Typical Characteristics
(Unless otherwise noted, VIN= 5V, TA= 25°C)
Load Transient Response
100 µs/div
AAT3216
150mA MicroPower™ LDO with PowerOK
6 3216.2004.01.0.94
IN
V (V)
Turn On Time and POK Delay
V
(2V/div)
ENABLE
Turn Off Time with POK Delay
VEN (2V/div)
V
(500mV/div)
OUT
V
V
POK
Time (10µs/div)
(500mV/div)
Time (200µs/div)
POK
V
OUT
(2V/div)
(2V/div)
Line Transient Response
OUT
V (V)
2.90
2.85
2.80
2.75
2.70
2.65
2.60
V
I
OUT
OUT
6
V
5
IN
4
3
2
1
V
OUT
0
-1
-2
3.25
3.20
3.15
3.10
3.05
3.00
2.95
2.90
2.85
V (V)
OUT
Time (100 µs/div)
500
400
300
200
100
0
-100
I
OUT
(mA)
Over Current Protection
1200
1000
800
600
(mA)
400
OUT
I
200
0
-200
Time (20 ms/div)
VIN (2V/div)
V
(2V/div)
OUT
V
(1V/div)
POK
POK Output Response
Time (200µs/div.)
Page 7
AAT3216
150mA MicroPower™ LDO with PowerOK
3216.2004.01.0.94 7
Typical Characteristics
(Unless otherwise noted, VIN= 5V, TA= 25°C)
AAT3216 Self Noise
10
1
0.1
Noise Amplitude (µV/rtHz)
0.01
0.01 0.1 1 10 100 1000
Frequency (kHz)
V
and V
EN(H)
1.250
1.225
1.200
1.175
1.150
(V)
EN
1.125
V
1.100
1.075
1.050
2.5 3.0 3.5 4.0 4.5 5.0 5.5
V
EN(H)
EN(L)
V
EN(L)
vs. V
IN
VIN (V)
Page 8
AAT3216
150mA MicroPower™ LDO with PowerOK
8 3216.2004.01.0.94
Functional Description
The AAT3216 is intended for LDO regulator appli­cations where output current load requirements range from no load to 150mA.
The advanced circuit design of the AAT3216 pro­vides excellent transient response and fast turn-on ability. The LDO regulator output has been specif­ically optimized to function with low cost, low ESR ceramic capacitors. However, the design will allow for operation over a wide range of capacitor types.
The AAT3216 has an integrated Power-OK com­parator which indicates when the output is out of regulation.
The device enable circuit is provided to shutdown the LDO regulator for power conservation in portable products. The enable circuit has an additional out­put capacitor discharge circuit to assure sharp appli­cation circuit turn off upon device shutdown.
This LDO regulator has complete short circuit and thermal protection. The integral combination of these two internal protection circuits give the AAT3216 a comprehensive safety system during extreme adverse operating conditions. Device power dissipation is limited to the package type and thermal dissipation properties. Refer to the thermal considerations discussion in the section for details on device operation at maximum output cur­rent loads.
Functional Block Diagram
IN
EN
POK
OUT
Over-Current Protection
Over-Temperature
Protection
Error
Amplifier
Voltage
Reference
94%
GND
Page 9
Applications Information
To assure the maximum possible performance is obtained from the AAT3216, please refer to the fol­lowing application recommendations.
Input Capacitor
Typically a 1µF or larger capacitor is recommend­ed for CINin most applications. A CINcapacitor is not required for basic LDO regulator operation. However, if the AAT3216 is physically located more than 3 centimeters from an input power source, a CINcapacitor will be needed for stable operation. CINshould be located as close to the device VINpin as practically possible. CINvalues greater than 1µF will offer superior input line transient response and will assist in maximizing the highest possible power supply ripple rejection.
Ceramic, tantalum or aluminum electrolytic capaci­tors may be selected for CIN. There is no specific capacitor ESR requirement for CIN. However, for 150mA LDO regulator output operation, ceramic capacitors are recommended for CINdue to their inherent capability over tantalum capacitors to with­stand input current surges from low impedance sources such as batteries in portable devices.
Output Capacitor
For proper load voltage regulation and operational stability, a capacitor is required between pins V
OUT
and GND. The C
OUT
capacitor connection to the LDO regulator ground pin should be made as direct as practically possible for maximum device performance.
The AAT3216 has been specifically designed to func­tion with very low ESR ceramic capacitors. For best performance, ceramic capacitors are recommended.
Typical output capacitor values for maximum output current conditions range from 1µF to 10µF. Applications utilizing the exceptionally low output noise and optimum power supply ripple rejection characteristics of the AAT3216 should use 2.2µF or greater for C
OUT
. If desired, C
OUT
may be increased
without limit.
In low output current applications where output load is less then 10mA, the minimum value for C
OUT
can be as low as 0.47µF.
Capacitor Characteristics
Ceramic composition capacitors are highly recom­mended over all other types of capacitors for use with the AAT3216. Ceramic capacitors offer many advantages over their tantalum and aluminum elec­trolytic counterparts. A ceramic capacitor typically has very low ESR, is lower cost, has a smaller PCB footprint and is non-polarized. Line and load tran­sient response of the LDO regulator is improved by using low ESR ceramic capacitors. Since ceramic capacitors are non-polarized, they are not prone to incorrect connection damage.
Equivalent Series Resistance (ESR): ESR is a very important characteristic to consider when selecting a capacitor. ESR is the internal series resistance associated with a capacitor, which includes lead resistance, internal connections, size and area, material composition and ambient tem­perature. Typically capacitor ESR is measured in milliohms for ceramic capacitors and can range to more than several ohms for tantalum or aluminum electrolytic capacitors.
Ceramic Capacitor Materials: Ceramic capaci­tors less than 0.1µF are typically made from NPO or COG materials. NPO and COG materials are typically tight tolerance very stable over tempera­ture. Larger capacitor values are typically com­posed of X7R, X5R, Z5U and Y5V dielectric mate­rials. Large ceramic capacitors, typically greater then 2.2µF are often available in the low cost Y5V and Z5U dielectrics. These two material types are not recommended for use with LDO regulators since the capacitor tolerance can vary more than ±50% over the operating temperature range of the device. A 2.2µF Y5V capacitor could be reduced to 1µF over temperature, this could cause problems for circuit operation. X7R and X5R dielectrics are much more desirable. The temperature tolerance of X7R dielectric is better than ±15%.
Capacitor area is another contributor to ESR. Capacitors which are physically large in size will have a lower ESR when compared to a smaller sized capacitor of an equivalent material and capacitance value. These larger devices can improve circuit tran­sient response when compared to an equal value capacitor in a smaller package size.
AAT3216
150mA MicroPower™ LDO with PowerOK
3216.2004.01.0.94 9
Page 10
AAT3216
150mA MicroPower™ LDO with PowerOK
10 3216.2004.01.0.94
Applications Information
Consult capacitor vendor data sheets carefully when selecting capacitors for LDO regulators.
POK Output
The AAT 3216 features an integrated Power-OK comparator which can be used as an error flag. The POK open-drain output goes low when OUT is 6% below its nominal regulation voltage. Connect a pull-up resistor from POK to OUT or IN. A delayed POK signal can be implemented with a capacitor in parallel with the pull-up resistor.
Enable Function
The AAT3216 features an LDO regulator enable/ disable function. This pin (EN) is active high and is compatible with CMOS logic. To assure the LDO regulator will switch on, the EN turn on control level must be greater than 2.0 volts. The LDO regulator will go into the disable shutdown mode when the voltage on the EN pin falls below 0.6 volts. If the enable function is not needed in a specific applica­tion, it may be tied to VINto keep the LDO regula­tor in a continuously on state.
When the LDO regulator is in the shutdown mode,
an internal 1.5kΩ resistor is connected between
V
OUT
and GND. This is intended to discharge C
OUT
when the LDO regulator is disabled. The internal
1.5kΩ has no adverse effect on device turn on time.
Short Circuit Protection
The AAT3216 contains an internal short circuit pro­tection circuit that will trigger when the output load current exceeds the internal threshold limit. Under short circuit conditions the output of the LDO regu­lator will be current limited until the short circuit condition is removed from the output or LDO regu­lator package power dissipation exceeds the device thermal limit.
Thermal Protection
The AAT3216 has an internal thermal protection cir­cuit which will turn on when the device die temper­ature exceeds 150°C. The internal thermal protec­tion circuit will actively turn off the LDO regulator
output pass device to prevent the possibility of over temperature damage. The LDO regulator output will remain in a shutdown state until the internal die temperature falls back below the 150°C trip point.
The combination and interaction between the short circuit and thermal protection systems allow the LDO regulator to withstand indefinite short circuit conditions without sustaining permanent damage.
No-Load Stability
The AAT3216 is designed to maintain output volt­age regulation and stability under operational no­load conditions. This is an important characteristic for applications where the output current may drop to zero.
Reverse Output to Input Voltage Conditions and Protection
Under normal operating conditions a parasitic diode exists between the output and input of the LDO regulator. The input voltage should always remain greater then the output load voltage main­taining a reverse bias on the internal parasitic diode. Conditions where V
OUT
might exceed V
IN
should be avoided since this would forward bias the internal parasitic diode and allow excessive current flow into the V
OUT
pin possibly damaging
the LDO regulator.
In applications where there is a possibility of V
OUT
exceeding VINfor brief amounts of time during nor­mal operation, the use of a larger value CINcapaci­tor is highly recommended. A larger value of C
IN
with respect to C
OUT
will effect a slower CINdecay
rate during shutdown, thus preventing V
OUT
from exceeding VIN. In applications where there is a greater danger of V
OUT
exceeding VINfor extended periods of time, it is recommended to place a schot­tky diode across VINto V
OUT
(connecting the cath-
ode to VINand anode to V
OUT
). The Schottky diode
forward voltage should be less than 0.45 volts.
Thermal Considerations and High Output Current Applications
The AAT3216 is designed to deliver a continuous output load current of 150mA under normal operat­ing conditions.
Page 11
Applications Information
The limiting characteristic for the maximum output load current safe operating area is essentially package power dissipation and the internal preset thermal limit of the device. In order to obtain high operating currents, careful device layout and circuit operating conditions need to be taken into account.
The following discussions will assume the LDO reg­ulator is mounted on a printed circuit board utilizing the minimum recommended footprint as stated in the layout considerations section of the document.
At any given ambient temperature (TA) the maxi­mum package power dissipation can be deter­mined by the following equation:
P
D(MAX)
= [T
J(MAX)
- T
A
] / Θ
JA
Constants for the AAT3216 are T
J(MAX)
, the maxi-
mum junction temperature for the device which is
125°C and Θ
JA
= 190°C/W, the package thermal resistance. Typically, maximum conditions are cal­culated at the maximum operating temperature where TA= 85°C, under normal ambient conditions TA= 25°C. Given TA= 85°, the maximum package power dissipation is 211mW. At TA= 25°C°, the maximum package power dissipation is 526mW.
The maximum continuous output current for the AAT3216 is a function of the package power dissi­pation and the input to output voltage drop across the LDO regulator. Refer to the following simple equation:
I
OUT(MAX)
< P
D(MAX)
/ (VIN- V
OUT
)
For example, if VIN= 5V, V
OUT
= 3V and TA= 25°,
I
OUT(MAX)
< 264mA. If the output load current were to exceed 264mA or if the ambient temperature were to increase, the internal die temperature will increase. If the condition remained constant, the LDO regula­tor thermal protection circuit will activate.
To figure what the maximum input voltage would be for a given load current refer to the following equa­tion. This calculation accounts for the total power dissipation of the LDO Regulator, including that caused by ground current.
P
D(MAX)
= (VIN- V
OUT)IOUT
+ (VINx I
GND
)
This formula can be solved for V
IN
to determine the
maximum input voltage.
V
IN(MAX)
= (P
D(MAX)
+ (V
OUT
x I
OUT
)) / (I
OUT
+ I
GND
)
The following is an example for an AAT3216 set for a 2.5 volt output:
From the discussion above, P
D(MAX)
was deter-
mined to equal 526mW at TA= 25°C.
V
OUT
= 2.5 volts
I
OUT
= 150mA
I
GND
= 150µA
V
IN(MAX)
=(526mW+(2.5Vx150mA))/(150mA +150µA)
V
IN(MAX)
= 6.00V
Thus, the AAT3216 can sustain a constant 2.5V output at a 150mA load current as long as V
IN
is ≤
6.00V at an ambient temperature of 25°C. 6.0V is the absolute maximum voltage where an AAT3216 would never be operated, thus at 25°C, the device would not have any thermal concerns or opera­tional V
IN(MAX)
limits.
This situation can be different at 85°C. The follow­ing is an example for an AAT3216 set for a 2.5 volt output at 85°C:
From the discussion above, P
D(MAX)
was deter-
mined to equal 211mW at TA= 85°C.
V
OUT
= 2.5 volts
I
OUT
= 150mA
I
GND
= 150uA
V
IN(MAX)
=(211mW+(2.5Vx150mA))/(150mA +150uA)
V
IN(MAX)
= 3.90V
Higher input to output voltage differentials can be obtained with the AAT3216, while maintaining device functions within the thermal safe operating area. To accomplish this, the device thermal resistance must be reduced by increasing the heat sink area or by operating the LDO regulator in a duty cycled mode.
For example, an application requires VIN= 4.2V while V
OUT
= 2.5V at a 150mA load and TA= 85°C. VINis greater than 3.90V, which is the maximum safe continuous input level for V
OUT
= 2.5V at 150mA for TA= 85°C. To maintain this high input voltage and output current level, the LDO regulator
AAT3216
150mA MicroPower™ LDO with PowerOK
3216.2004.01.0.94 11
Page 12
AAT3216
150mA MicroPower™ LDO with PowerOK
12 3216.2004.01.0.94
must be operated in a duty cycled mode. Refer to the following calculation for duty cycle operation:
P
D(MAX)
is assumed to be 211mW
I
GND
= 150µA
I
OUT
= 150mA
VIN= 4.2 volts
V
OUT
= 2.5 volt
%DC=100(P
D(MAX)
/((VIN-V
OUT)IOUT
+(VINxI
GND
))
%DC=100(211mW/((4.2V-2.5V)150mA+(4.2Vx150µA))
%DC = 85.54%
For a 150mA output current and a 2.7volt drop across the AAT3216 at an ambient temperature of 85°C, the maximum on time duty cycle for the device would be 85.54%.
The following family of curves show the safe oper­ating area for duty cycled operation from ambient room temperature to the maximum operating level.
Duty Cycle (%)
Voltage Drop (V)
Device Duty Cycle vs. V
V
= 2.5V @ 25 C
OUT
3.5
3
2.5
2
1.5
1
0.5
0
0 10203040 5060708090100
Device Duty Cycle vs. V
V
= 2.5V @ 50 C
OUT
3.5
3
2.5
2
1.5
1
0.5
Voltage Drop (V)
0
0 10203040 5060708090100
Duty Cycle (%)
DROP
200mA
DROP
200mA
150mA
Device Duty Cycle vs. V
V
= 2.5V @ 85 C
OUT
3.5
3
2.5
2
1.5
1
0.5
Voltage Drop (V)
0
0 10203040 5060708090100
200mA
150mA
Duty Cycle (%)
DROP
100mA
Page 13
AAT3216
150mA MicroPower™ LDO with PowerOK
3216.2004.01.0.94 13
Applications Information
High Peak Output Current Applications
Some applications require the LDO regulator to operate at continuous nominal level with short duration high current peaks. The duty cycles for both output current levels must be taken into account. To do so, one would first need to calcu­late the power dissipation at the nominal continu­ous level, then factor in the additional power dissi­pation due to the short duration high current peaks.
For example, a 2.5V system using a AAT3216IGV-
2.5-T1 operates at a continuous 100mA load cur­rent level and has short 150mA current peaks. The current peak occurs for 378µs out of a 4.61ms peri­od. It will be assumed the input voltage is 4.2V.
First the current duty cycle in percent must be cal­culated:
% Peak Duty Cycle: X/100 = 378µs/4.61ms % Peak Duty Cycle = 8.2%
The LDO Regulator will be under the 100mA load for 91.8% of the 4.61ms period and have 150mA peaks occurring for 8.2% of the time. Next, the continuous nominal power dissipation for the 100mA load should be determined then multiplied by the duty cycle to conclude the actual power dis­sipation over time.
P
D(MAX)
= (VIN- V
OUT)IOUT
+ (VINx I
GND
)
P
D(100mA)
= (4.2V - 2.5V)100mA + (4.2V x 150µA)
P
D(100mA)
= 170.6mW
P
D(91.8%D/C)
= %DC x P
D(100mA)
P
D(91.8%D/C)
= 0.918 x 170.6mW
P
D(91.8%D/C)
= 156.6mW
The power dissipation for 100mA load occurring for
91.8% of the duty cycle will be 156.6mW. Now the power dissipation for the remaining 8.2% of the duty cycle at the 150mA load can be calculated:
P
D(MAX)
= (VIN- V
OUT)IOUT
+ (VINx I
GND
)
P
D(150mA)
= (4.2V - 2.5V)150mA + (4.2V x 150mA)
P
D(150mA)
= 255.6mW
P
D(8.2%D/C)
= %DC x P
D(150mA)
P
D(8.2%D/C)
= 0.082 x 255.6mW
P
D(8.2%D/C)
= 21mW
The power dissipation for 150mA load occurring for
8.2% of the duty cycle will be 21mW. Finally, the two power dissipation levels can summed to deter­mine the total true power dissipation under the var­ied load.
P
D(total)
= P
D(100mA)
+ P
D(150mA)
P
D(total)
= 156.6mW + 21mW
P
D(total)
= 177.6mW
The maximum power dissipation for the AAT3216 operating at an ambient temperature of 85°C is 211mW. The device in this example will have a total power dissipation of 177.6mW. This is well within the thermal limits for safe operation of the device.
Page 14
AAT3216
150mA MicroPower™ LDO with PowerOK
14 3216.2004.01.0.94
Ordering Information
Note: Sample stock is generally held on all part numbers listed in BOLD. Note 1: XYY = assembly and date code.
Output Voltage Package Marking
1
Part Number (Tape and Reel)
1.2V SOT23-5 EAXYY AAT3216IGV-1.2-T1
1.5V SOT23-5 KJXYY AAT3216IGV-1.5-T1
1.8V SOT23-5 AAT3216IGV-1.8-T1
2.0V SOT23-5 AAT3216IGV-2.0-T1
2.3V SOT23-5 AAT3216IGV-2.3-T1
2.5V SOT23-5 KKXYY AAT3216IGV-2.5-T1
2.7V SOT23-5 AAT3216IGV-2.7-T1
2.8V SOT23-5 ELXYY AAT3216IGV-2.8-T1
2.85V SOT23-5 FSXYY AAT3216IGV-2.85-T1
3.0V SOT23-5 AAT3216IGV-3.0-T1
3.3V SOT23-5 HQXYY AAT3216IGV-3.3-T1
3.5V SOT23-5 IYXYY AAT3216IGV-3.5-T1
1.2V SC70JW-8 AAT3216IJS-1.2-T1
1.5V SC70JW-8 AAT3216IJS-1.5-T1
1.8V SC70JW-8 AAT3216IJS-1.8-T1
2.0V SC70JW-8 AAT3216IJS-2.0-T1
2.3V SC70JW-8 AAT3216IJS-2.3-T1
2.5V SC70JW-8 AAT3216IJS-2.5-T1
2.7V SC70JW-8 AAT3216IJS-2.7-T1
2.8V SC70JW-8 AAT3216IJS-2.8-T1
2.85V SC70JW-8 AAT3216IJS-2.85-T1
3.0V SC70JW-8 KGXYY AAT3216IJS-3.0-T1
3.3V SC70JW-8 AAT3216IJS-3.3-T1
3.5V SC70JW-8 AAT3216IJS-3.5-T1
Page 15
Package Information
SOT23-5
SC70JW-8
All dimensions in millimeters
AAT3216
150mA MicroPower™ LDO with PowerOK
3216.2004.01.0.94 15
2.85 ± 0.15
1.90 BSC
0.95 BSC
0.60 REF
0.125
±
1.575
10° ± 5°
0.40 ± 0.10
0.50 BSC 0.50 BSC 0.50 BSC
0.075 ± 0.075
0.20
±
1.10
0.20
±
2.80
0.25
±
1.20
4° ± 4°
1.75 ± 0.10
2.20 ± 0.20
0.60 REF
0.15 ± 0.07
0.45 ± 0.15 0.10 BSC
GAUGE PLANE
0.225 ± 0.075
7° ± 3°
2.00 ± 0.20
0.85 ± 0.15
1.10 MAX
0.100
0.15 ± 0.05
0.45 ± 0.10
2.10 ± 0.30
4° ± 4°
0.048REF
0.05 ± 0.05
Page 16
AAT3216
150mA MicroPower™ LDO with PowerOK
16 3216.2004.01.0.94
Advanced Analogic Technologies, Inc.
830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611
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