AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 1
SysPwr™
Typical Application
AAT2500 Step-Down Converter Efficiency
Load Current (mA)
Efficiency (%)
60
65
70
75
80
85
90
95
100
0.1 1 10 100 1000
VIN = 3.3V
1.8V
2.5V
4.7µH
L1
4.7µF
C1
2.2µF
C4
10µF
C3
10nF
C5
PGND 1
LX 2
VP
3VCC 4
ENLDO
9
EN 10
FB 11
SGND 12
VLDO
5
OUT
6
GND
8
BYP
7
AAT2500
U1
L1 Sumida CD RH 3D 16-4R7 C 1 M urata GR M219R6 1A475KE19
C3 Murat a GR M21BR60J 106KE19
VIN = 2.7V to 5.5V
3.3V at 300mA
2.5V at 400mA
General Description
The AAT2500 is a member of AnalogicTech's Total
Power Management IC™ (TPMIC™) product fam-
ily. It is a low dropout (LDO) linear regulator and a
step-down converter with an input voltage range of
2.7V to 5.5V, making it ideal for applications with
single lithium-ion/polymer batteries.
The LDO has an independent input and is capable
of delivering up to 300mA. The linear regulator has
been designed for high-speed turn-on and turn-off
performance, fast transient response, and good
power supply rejection ratio (PSRR). Other fea-
tures include low quiescent current and a low
dropout voltage.
The 400mA step-down converter is designed to
minimize external component size and cost while
maintaining a low 25µA no load quiescent current.
Peak current mode control with internal compen-
sation provides a stable converter with a low equiv-
alent series resistance (ESR) ceramic output
capacitor for extremely low output ripple.
For maximum battery life, the step-down converter
increases to 100% duty cycle and has a typical
180mV dropout voltage at 400mA. The output volt-
age is either fixed or adjustable with an integrated
P- and N-channel MOSFET power stage and
1MHz switching frequency.
The AAT2500 is available in a 12-pin TDFN33
package, and is rated over a temperature range of
-40°C to +85°C.
Features
•V
IN Range: 2.7V to 5.5V
• 300mA LDO Current Output
• 400mV LDO Dropout Voltage at 300mA
• High Output Accuracy: ±1.5%
• Fast LDO Line / Load Transient Response
• 400mA, 96% Efficiency Step-Down Converter
• 25µA No Load Quiescent Current for Step-
Down Converter
• Shutdown Current <1µA
• Low RDS(ON) 0.4ΩIntegrated Power Switches
• Low Dropout 100% Duty Cycle
• 1MHz Switching Frequency
• Internal Soft Start
• Over-Temperature Protection
• Current Limit Protection
• Available in TDFN33-12 Package
• -40°C to +85°C Temperature Range
Applications
• Cellular Phones
• Digital Cameras
• Handheld instruments
• Microprocessor/DSP Core/IO Power
• PDAs and Handheld Computers
• Portable Media Players
AAT2500
1MHz Step-Down Converter/LDO Regulator
22500.2005.08.1.9
Pin Descriptions
Pin Configuration TDFN33-12
(TopView)
PGND
LX
VP
1
VCC
VLDO
OUT
SGND
FB
EN
ENLDO
GND
BYP
2
3
4
5
6
12
11
10
9
8
7
Pin # Symbol Function
1 PGND Step-down converter power ground return pin. Connect to the output and input capaci-
tor return. See section on PCB layout guidelines and evaluation board layout diagram.
2 LX Power switching node. Output switching node that connects to the output inductor.
3 VP Step-down converter power stage supply voltage. Must be closely decoupled to PGND.
4 VCC Step-down converter bias supply. Connect to VP.
5 VLDO LDO input voltage; should be decoupled with 1µF or greater capacitor.
6 OUT 300mA LDO output pin. A 2.2µF or greater output low-ESR ceramic capacitor is
required for stability.
7 BYP Bypass capacitor for the LDO. To improve AC ripple rejection, connect a 10nF capaci-
tor to GND. This will also provide a soft-start function.
8 GND LDO ground connection pin.
9 ENLDO Enable pin for LDO. When connected low, LDO is disabled and consumes less than
1µA of current.
10 EN Step-down converter enable. When connected low, LDO is disabled and consumes
less than 1µA.
11 FB Step-down converter feedback input pin. For fixed output voltage versions, this pin is
connected to the converter output, forcing the converter to regulate to the specific volt-
age. For adjustable output versions, an external resistive divider ties to this point and
programs the output voltage to the desired value.
12 SGND Step-down converter signal ground. For external feedback, return the feedback resis-
tive divider to this ground. For internal fixed version, tie to the point of load return. See
section on PCB layout guidelines and evaluation board layout diagram.
EP Exposed paddle (bottom). Use properly sized vias for thermal coupling to the ground
plane. See section on PCB layout guidelines.
AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 3
Absolute Maximum Ratings1
Thermal Information
Symbol Description Value Units
PDMaximum Power Dissipation 2 W
θJA Thermal Resistance250 °C/W
Symbol Description Value Units
VP, VLDO Input Voltages to GND 6.0 V
VLX LX to GND -0.3 to VP+ 0.3 V
VFB FB to GND -0.3 to VP+ 0.3 V
VEN EN to GND -0.3 to 6.0 V
TJOperating Junction Temperature Range -40 to 150 °C
TLEAD Maximum Soldering Temperature (at leads, 10 sec) 300 °C
1. 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.
2. Mounted on an FR4 board with exposed paddle connected to ground plane.
AAT2500
1MHz Step-Down Converter/LDO Regulator
42500.2005.08.1.9
Electrical Characteristics1
Symbol Description Conditions Min Typ Max Units
LDO VIN = VLDO = VOUT(NOM) + 1V for VOUT options greater than 1.5V. VIN = VLDO = 2.5V for VOUT ≤1.5V. IOUT =
1mA, COUT = 2.2µF, CIN = 1µF, TA= -40°C to +85°C, unless otherwise noted. Typical values are TA= 25°C.
TA= 25°C -1.5 1.5
VOUT Output Voltage Tolerance IOUT = 1mA to 300mA TA= -40°C -2.5 2.5 %
to 85°C
VIN Input Voltage VOUT+VDO25.5 V
VDO Dropout Voltage3, 4 IOUT = 300mA 400 600 mV
∆VOUT/Line Regulation VIN = VOUT + 1V to 5V 0.09 %/V
VOUT*∆VIN
∆VOUT(Line) Dynamic Line Regulation IOUT = 300mA, VIN = VOUT + 1V to 2.5 mV
VOUT + 2V, TR/TF= 2µS
∆VOUT(Load) Dynamic Load Regulation IOUT = 1mA to 300mA, TR<5µS 60 mV
IOUT Output Current VOUT > 1.3V 300 mA
ISC Short-Circuit Current VOUT < 0.4V 600 mA
IQLDO LDO Quiescent Current VIN = 5V, No Load, ENLDO = VIN 70 125 µA
ISHDN Shutdown Current VIN = 5V; ENLDO = GND, 1.0 µA
EN = SGND = PGND 1kHz 67
PSRR Power Supply Rejection Ratio IOUT = 10mA, CBYP = 10nF 10kHz 47 dB
1MHz 45
TSD Over-Temperature Shutdown 145 °C
Threshold
THYS Over-Temperature Shutdown 12 °C
Hysteresis
eNOutput Noise eNBW = 300Hz to 50kHz 50 µVRMS
TCOutput Voltage Temperature 22 ppm/°C
Coefficient
1. The AAT2500 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured
by design, characterization, and correlation with statistical process controls.
2. To calculate the minimum LDO input voltage, use the following equation: VIN(MIN) = VOUT(MAX) + VDO(MAX), as long as VIN ≥2.5V.
3. For VOUT <2.1V, VDO = 2.5 - VOUT.
4. VDO is defined as VIN - VOUT when VOUT is 98% of nominal.
AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 5
Electrical Characteristics1
Symbol Description Conditions Min Typ Max Units
Buck Converter Typical values are TA= 25°C, VIN = VCC = Vp = 3.6V.
VIN Input Voltage 2.7 5.5 V
VIN Rising 2.6 V
VUVLO UVLO Threshold Hysteresis 100 mV
VIN Falling 1.8 V
VOUT Output Voltage Tolerance IOUT = 0 to 400mA, -3.0 +3.0 %
VIN = 2.7V to 5.5V
VOUT Output Voltage Range Fixed Output Version 0.6 4.0 V
Adjustable Output Version20.6 2.5
IQBUCK Step-Down Converter ENLDO = GND, No Load, 25 50 µA
Quiescent Current 0.6V Adjustable Model
ISHDN Shutdown Current EN = SGND = PGND, ENLDO = GND 1.0 µA
ILIM P-Channel Current Limit 600 mA
RDS(ON)H High Side Switch On 0.45 Ω
Resistance
RDS(ON)L Low Side Switch On 0.4 Ω
Resistance
ILXLK LX Leakage Current VIN = 5.5V, VLX = 0 - VIN 1.0 µA
EN = SGND = PGND
ILXLK, R LX Reverse Leakage Current VIN = Open, VLX = 5.5V, 1.0 µA
(fixed) EN = SGND = PGND
VLinereg Line Regulation VIN = 2.7V to 5.5V 0.2 %/V
VFB FB Threshold Voltage 0.6V Output, No Load, TA= 25°C 597 600 615 mV
Accuracy
IFB FB Leakage Current 0.6V Output 0.2 µA
RFB FB Impedance >0.6V Output 250 kΩ
FOSC Oscillator Frequency TA= 25°C 0.7 1.0 1.5 MHz
TSD Over-Temperature Shutdown 140 °C
Threshold
THYS Over-Temperature Shutdown 15 °C
Hysteresis
Logic Signals
VEN(L) Enable Threshold Low 0.6 V
VEN(H) Enable Threshold High 1.5 V
IEN(H) Leakage Current 1.0 1.0 µA
1. The AAT2500 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured
by design, characterization, and correlation with statistical process controls.
2. For adjustable version with higher than 2.5V output, please consult your AnalogicTech representative.
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA= 25°C.
LDO Initial Power-Up Response Time
(CBYP = 10nF; EN = GND; ENLDO = VIN)
400
µµ
s/div
VENLDO (5V/div)
VOUT (1V/div)
LDO Output Voltage vs. Temperature
(EN = GND; ENLDO = VIN)
1.196
1.197
1.198
1.199
1.200
1.201
1.202
1.203
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Temperature (°C)
Output Voltage (V)
LDO Ground Current vs. Input Voltage
(EN = GND; ENLDO = VIN)
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
2 2.5 3 3.5 4.545
Input Voltage (V)
Ground Current (µA)
IOUT=0mA
IOUT=10mA
IOUT=50mA
IOUT=150mA
IOUT=300mA
LDO Dropout Voltage vs. Output Current
(EN = GND; ENLDO = VIN)
0
50
100
150
200
250
300
350
400
450
500
0 50 100 150 200 250 300
Output Current (mA)
Dropout Voltage (mV)
85°C
25°C
-40°C
LDO Dropout Characteristics
(EN = GND; ENLDO = VIN)
2.00
2.20
2.40
2.60
2.80
3.00
3.20
2.70 2.80 2.90 3.00 3.10 3.20 3.30
Input Voltage (V)
Output Voltage (V)
IOUT = 300mA
IOUT = 150mA
IOUT = 100mA
IOUT = 50mA
IOUT = 10mA
IOUT = 0mA
LDO Dropout Voltage vs. Temperature
(EN = GND; ENLDO = VIN)
0
60
120
180
240
300
360
420
480
540
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120
Temperature (°C)
Dropout Voltage (mV)
IL = 300mA
IL = 150mA IL = 100mA
IL = 50mA
AAT2500
1MHz Step-Down Converter/LDO Regulator
62500.2005.08.1.9
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA= 25°C, VIN = VLDO = VCC = VP.
LDO Self Noise
(EN = GND; ENLDO = VIN)
0.001
0.01
0.1
1
10
0.01 0.1 1 10 100 1000 10000
Frequency (kHz)
Noise Amplitude (µV/rtHz)
Band Power:
300Hz to 50kHz = 44.6µVrms
100Hz to 100kHz = 56.3µVrms
LDO Load Transient Response 300mA
(CBYP = 10nF; EN = GND; ENLDO = VIN)
2.10
2.20
2.30
2.40
2.50
2.60
2.70
2.80
2.90
3.00
10µ
µ
s/div
Output Voltage (V)
-100
0
100
200
300
400
500
600
700
800
Output Current (mA)
VOUT
IOUT
LDO Load Transient Response
(CBYP = 10nF; EN = GND; ENLDO = VIN)
2.60
2.65
2.70
2.75
2.80
2.85
2.90
100µS/div
Output Voltage (V)
-100
0
100
200
300
400
500
Output Current (mA)
VOUT
IOUT
LDO Line Transient Response
(CBYP = 10nF; EN = GND; ENLDO = VIN)
2.98
2.99
3.00
3.01
3.02
3.03
3.04
100µs/div
Input Voltage (V)
0
1
2
3
4
5
6
Output Voltage (V)
VIN
VOUT
LDO Turn-On Time From Enable (VIN present)
(CBYP = 10nF; EN = GND; ENLDO = VIN)
5µ
µ
s/div
VIN = 4V
VOUT = 1V/div
VENLDO = 5V/div
LDO Turn-Off Response Time
(CBYP = 10nF; EN = GND; ENLDO = VIN)
50µs/div
VENLDO (5V/div)
VOUT (1V/div)
AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 7
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA= 25°C.
Step-Down Converter DC Regulation
(VOUT = 1.8V; EN = VIN; ENLDO = GND)
Output Current (mA)
Output Error (%)
-2.0
-1.0
0.0
1.0
2.0
0.1 1.0 10 100 1000
VIN = 2.7V
VIN = 3.6V
VIN = 4.2V
Step-Down Converter Efficiency vs. Load
(VOUT = 1.8V; EN = VIN; ENLDO = GND)
Output Current (mA)
Efficiency (%)
50
60
70
80
90
100
0.1 1.0 10 100 1000
VIN = 2.7V VIN = 3.6V
VIN = 4.2V
Step-Down Converter Load Regulation
(VOUT = 2.5V; EN = VIN; ENLDO = GND)
Output Current (mA)
Output Error (%)
-2.0
-1.0
0.0
1.0
2.0
0.1 1.0 10 100 1000
VIN = 3.0V
VIN = 3.3V
VIN = 3.6V
Step-Down Converter Efficiency vs. Load
(VOUT = 2.5V; EN = VIN; ENLDO = GND)
Output Current (mA)
Efficiency (%)
60
70
80
90
100
0.1 1.0 10 100 1000
VIN = 3.3V
VIN = 3.6V
VIN = 3.0V
LDO ENLDO vs. VIN
1.050
1.075
1.100
1.125
1.150
1.175
1.200
1.225
1.250
2.5 3.0 3.5 4.0 4.5 5.0 5.5
Input Voltage (V)
VIH
VIL
Over-Current Protection
(EN = GND; ENLDO = VIN)
Time (50ms/div)
Output Current (mA)
-200
0
200
400
600
800
1000
1200
AAT2500
1MHz Step-Down Converter/LDO Regulator
82500.2005.08.1.9
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA= 25°C.
Step-Down Converter
N-Channel RDS(ON) vs. Input Voltage
(EN = VIN; ENLDO = GND)
Input Voltage (V)
RDS(ON) (mΩ
Ω
)
300
350
400
450
500
550
600
650
700
750
2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
25°C
120°C100°C
85°C
Step-Down Converter
P-Channel RDS(ON) vs. Input Voltage
(EN = VIN; ENLDO = GND)
Input Voltage (V)
RDS(ON) (mΩ
Ω
)
300
350
400
450
500
550
600
650
700
750
2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
25°C
120°C 100°C
85°C
Step-Down Converter
Input Current vs. Input Voltage
(VO = 1.8V; EN = VIN; ENLDO = GND)
Input Voltage (V)
Input Current (µ
µ
A)
85°C
25°C
-40°C
15
20
25
30
35
2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Step-Down Converter
Switching Frequency vs. Temperature
(VIN = 3.6V; VO = 1.5V; EN = VIN; ENLDO = GND)
Temperature (°
°
C)
Frequency Variation
(%)
-0.20
-0.10
0.00
0.10
0.20
-40 -20 0 20 40 60 80 100
Step-Down Converter
Output Voltage Error vs. Temperature
(VIN = 3.6V; VO = 1.5V; EN = VIN; ENLDO = GND)
Temperature (°
°
C)
Output Error (%)
-2.0
-1.0
0.0
1.0
2.0
-40 -20 0 20 40 60 80 100
Step-Down Converter
Frequency vs. Input Voltage
(VOUT = 1.8V; EN = VIN; ENLDO = GND)
Input Voltage (V)
Frequency Variation (%)
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 9
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA= 25°C.
Step-Down Converter Soft Start
(VIN = 3.6V; VOUT = 1.8V; 400mA;
EN = VIN; ENLDO = GND)
Enable and Output Voltage
(top) (V)
Inductor Current
(bottom) (A)
250µ
µ
s/div
-4.0
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Step-Down Converter Line Regulation
(VOUT = 1.8V; EN = VIN; ENLDO = GND)
Input Voltage (V)
Accuracy (%)
-0.35
-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
IOUT = 400mA
IOUT = 100mA
IOUT = 10mA
Step-Down Converter Line Transient
(VOUT = 1.8V @ 400mA; EN = VIN; ENLDO = GND)
Output Voltage
(top) (V)
Input Voltage
(bottom) (V)
Time (25µ
µ
s/div)
1.50
1.55
1.60
1.65
1.70
1.75
1.80
1.85
1.90
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
Step-Down Converter Load Transient Response
(30mA - 300mA; VIN = 3.6V; VOUT = 1.8V;
C1 = 4.7µ
µ
F; EN = VIN; ENLDO = GND)
Output Voltage
(top) (V)
Load and Inductor Current
(200mA/div) (bottom)
Time (25µs/div)
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0 1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
300mA
30mA
Step-Down Converter Load Transient Response
(30mA - 300mA; VIN = 3.6V; VOUT = 1.8V; C1 = 10µ
µ
F;
C4 = 100pF; EN = VIN; ENLDO = GND)
Output Voltage (AC Coupled)
(top) (V)
Load and Inductor Current
(200mA/div) (bottom)
Time (25µs/div)
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0.1
0.0 1.2
1.4
0.8
0.6
1.0
0.2
0.4
-0.2
0.0
300mA
30mA
Step-Down Converter Load Transient Response
(30mA - 300mA; VIN = 3.6V; VOUT = 1.8V;
C1 = 10µ
µ
F; EN = VIN; ENLDO = GND)
Output Voltage
(top) (V)
Load and Inductor Current
(200mA/div) (bottom)
Time (25µs/div)
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0 1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
300mA
30mA
AAT2500
1MHz Step-Down Converter/LDO Regulator
10 2500.2005.08.1.9
Typical Characteristics
Unless otherwise noted, VIN = 5V, TA= 25°C.
Step-Down Converter Output Ripple
(VIN = 3.6V; VOUT = 1.8V; 400mA;
EN = VIN; ENLDO = GND)
Output Voltage (AC Coupled)
(top) (mV)
Inductor Current
(bottom) (A)
Time (250ns/div)
-120
-100
-80
-60
-40
-20
0
20
40
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 11
AAT2500
1MHz Step-Down Converter/LDO Regulator
12 2500.2005.08.1.9
Functional Block Diagram
Note: Internal resistor divider included for ≥1.2V versions. For low voltage versions, the feedback pin is tied directly to the error
amplifier input.
EN
LX
Error
Amp.
Logic
DH
DL PGND
VP
FB
GND
Voltage
Reference
Voltage
Reference
Error
Amp.
OUT
Control
Logic
VLDO
Fast Start
Control
ENLDO
BYP
SGND
VCC
See
Note
Over-Current
Protection
AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 13
Functional Description
The AAT2500 is a high performance power man-
agement IC comprised of a buck converter and a
linear regulator. The buck converter is a high effi-
ciency converter capable of delivering up to
400mA. Designed to operate at 1.0MHz, the con-
verter requires only three external components
(CIN, COUT, and LX) and is stable with a ceramic
output capacitor. The linear regulator delivers
300mA and is also stable with ceramic capacitors.
Linear Regulator
The advanced circuit design of the linear regulator
has been specifically optimized for very fast start-
up and shutdown timing. This proprietary CMOS
LDO has also been tailored for superior transient
response characteristics. These traits are particu-
larly important for applications that require fast
power supply timing.
The high-speed turn-on capability is enabled
through implementation of a fast-start control cir-
cuit, which accelerates the power-up behavior of
fundamental control and feedback circuits within
the LDO regulator. Fast turn-off time response is
achieved by an active output pull-down circuit,
which is enabled when the LDO regulator is
placed in shutdown mode. This active fast shut-
down circuit has no adverse effect on normal
device operation. 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.
A bypass pin has been provided to allow the addi-
tion of an optional voltage reference byp ass cap ac-
itor to reduce output self noise and increase power
supply ripple rejection. Device self noise and
PSRR will be improved by the addition of a small
ceramic capacitor in this pin. However, increased
values of CBYPASS may slow down the LDO regula-
tor turn-on time. The regulator comes with com-
plete short-circuit and thermal protection. The com-
bination of these two internal protection circuits
gives a comprehensive safety system to guard
against extreme adverse operating conditions.
The regulator features an enable/disable function.
This pin (ENLDO) is active high and is compatible
with CMOS logic. To assure the LDO regulator will
switch on, the ENLDO turn-on control level must be
greater than 1.5V. The LDO regulator will go into
the disable shutdown mode when the voltage on
the EN pin falls below 0.6V. If the enable function is
not needed in a specific application, it may be tied
to VIN to keep the LDO regulator in a continuously
on state.
When the regulator is in shutdown mode, an inter-
nal 1.5kΩresistor is connected between OUT and
GND. This is intended to discharge COUT when the
LDO regulator is disabled. The internal 1.5KΩ
resistor has no adverse impact on device turn-on
time.
Step-Down Converter
The AAT2500 buck is a constant frequency peak
current mode PWM converter with internal com-
pensation. It is designed to operate with an input
voltage range of 2.7V to 5.5V. The output voltage
ranges from 0.6V to the input voltage for the inter-
nally fixed version, and up to 2.5V for the external-
ly adjustable version. The 0.6V fixed model shown
in Figure 1 is also the adjustable version and is
externally programmable with a resistive divider, as
shown in Figure 2. The converter MOSFET power
stage is sized for 400mA load capability with up to
96% efficiency. Light load efficiency exceeds 80%
at a 500µA load.
Soft Start
The AAT2500 soft-start control prevents output
voltage overshoot and limits inrush current when
either the input power or the enable input is
applied. When pulled low, the enable input forces
the converter into a low-power, non-switching state
with a bias current of less than 1µA.
AAT2500
1MHz Step-Down Converter/LDO Regulator
14 2500.2005.08.1.9
Low Dropout Operation
For conditions where the input voltage drops to the
output voltage level, the converter duty cycle
increases to 100%. As 100% duty cycle is
approached, the minimum off-time initially forces
the high side on-time to exceed the 1MHz clock
cycle and reduce the effective switching frequency.
Once the input drops below the level where the out-
put can be regulated, the high side P-channel
MOSFET is turned on continuously for 100% duty
cycle. At 100% duty cycle, the output volt age tracks
the input voltage minus the IR drop of the high side
P-channel MOSFET RDS(ON).
Low Supply
The under-voltage lockout (UVLO) guarantees suf-
ficient VIN bias and proper operation of all internal
circuitry prior to activation.
Fault Protection
For overload conditions, the peak inductor current is
limited. Thermal protection disables switching when
the internal dissipation or ambient temperature
becomes excessive. The junction over-temperature
threshold is 140°C with 15°C of hysteresis.
Applications Information
Linear Regulator
Input and Output Capacitors: An input capacitor
is not required for basic operation of the linear reg-
ulator. However, if the AAT2500 is physically locat-
ed more than three centimeters from an input
power source, a CIN capacitor will be needed for
stable operation. Typically, a 1µF or larger capaci-
tor is recommended for CIN in most applications.
CIN should be located as closely to the device VIN
pin as practically possible.
An input capacitor greater than 1µF will offer supe-
rior input line transient response and maximize
power supply ripple rejection. Ceramic, tantalum,
or aluminum electrolytic capacitors may be select-
ed for CIN. There is no specific capacitor ESR
requirement for CIN. However, for 300mA LDO reg-
ulator output operation, ceramic capacitors are rec-
ommended for CIN due to their inherent capability
over tantalum capacitors to withstand input current
surges from low impedance sources such as bat-
teries in portable devices.
For proper load voltage regulation and operational
stability, a capacitor is required between OUT and
GND. The COUT capacitor connection to the LDO
regulator ground pin should be made as directly as
practically possible for maximum device perform-
ance. Since the regulator has been designed to
function with very low ESR capacitors, ceramic
capacitors in the 1.0µF to 10µF range are recom-
mended for best performance. Applications utilizing
Figure 1: AAT2500 Fixed Output. Figure 2: AAT2500 with Adjustable Step-Down
Output and Enhanced Transient Response.
L1
4.7µF
C1
VIN
R1
59k
R2
4.7µF
C4
10µF
C3
10nF
C5
VOUTLDO
VOUTBUCK
100pF
C8
PGND 1
LX 2
VP
3VCC 4
ENLDO
9
EN 10
FB 11
SGND 12
VLDO
5
OUT
6
GND
8
BYP
7
AAT2500
U1
L1
4.7µF
C1
VOUTBUCK
VIN
4.7µF
C4
10µF
C3
10nF
C5
VOUTLDO
PGND 1
LX 2
VP
3VCC 4
ENLDO
9
EN 10
FB 11
SGND 12
VLDO
5
OUT
6
GND
8
BYP
7
AAT2500
U1
the exceptionally low output noise and optimum
power supply ripple rejection should use 2.2µF or
greater for COUT. In low output current applications,
where output load is less than 10mA, the minimum
value for COUT can be as low as 0.47µF.
Equivalent Series Resistance: ESR is a very
important characteristic to consider when selecting a
capacitor . ESR is the internal series resist ance asso-
ciated with a capacitor that includes lead resist ance,
internal connections, size and area, material compo-
sition, and ambient temperature. Typically, capacitor
ESR is measured in milliohms for ceramic capaci-
tors and can range to more than several ohms for
tantalum or aluminum electrolytic capacitors.
Bypass Capacitor and Low Noise
Applications
A bypass capacitor pin is provided to enhance the
low noise characteristics of the LDO. The bypass
capacitor is not necessary for operation; however,
for best device performance, a small ceramic
capacitor in the range of 470pF to 10nF should be
placed between the bypass pin (BYP) and the
device ground pin (GND). To practically realize the
highest power supply ripple rejection and lowest
output noise performance, it is critical that the
capacitor connection between the BYP pin and
GND pin be direct and PCB traces should be as
short as possible.
DC leakage on this pin can affect the LDO regula-
tor output noise and voltage regulation perform-
ance. For this reason, the use of a low leakage,
high quality ceramic (NPO or C0G type) or film
capacitor is highly recommended.
Step-Down Converter
Inductor Selection: The step-down converter
uses peak current mode control with slope com-
pensation to maintain stability for duty cycles
greater than 50%. The output inductor value must
be selected so the inductor current down slope
meets the internal slope compensation require-
ments. The internal slope compensation for the
adjustable and low-voltage fixed versions of the
AAT2500 is 0.24A/µsec. This equates to a slope
compensation that is 75% of the inductor current
down slope for a 1.5V output and 4.7µH inductor.
This is the internal slope compensation for the
adjustable (0.6V) version or low-voltage fixed ver-
sions. When externally programming the 0.6V ver-
sion to 2.5V, the calculated inductance is 7.5µH.
In this case, a standard 10µH value is selected.
For high-voltage fixed versions (2.5V and above),
m = 0.48A/µsec. Table 1 displays inductor values
for the AAT2500 fixed and adjustable options.
0.75 ⋅ V
O
L = =
≈
3
⋅ V
O
= 3 ⋅ 2.5V = 7.5µH
m
0.75
⋅
V
O
0.24A
µsec
A
µsec
A
A
µsec
0.75 ⋅ V
O
m = = = 0.24
L
0.75 ⋅ 1.5V
4.7µH
A
µsec
AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 15
Table 1: Inductor Values.
Configuration Output Voltage Inductor Slope Compensation
0.6V Adjustable With 0.6V to 2.0V 4.7µH 0.24A/µsec
External Resistive Divider 2.5V 10µH 0.24A/µsec
Fixed Output 0.6V to 2.0V 4.7µH 0.24A/µsec
2.5V to 3.3V 4.7µH 0.48A/µsec
AAT2500
1MHz Step-Down Converter/LDO Regulator
16 2500.2005.08.1.9
Manufacturer's specifications list both the inductor
DC current rating, which is a thermal limitation, and
the peak current rating, which is determined by the
saturation characteristics. The inductor should not
show any appreciable saturation under normal load
conditions. Some inductors may meet the peak and
average current ratings yet result in excessive loss-
es due to a high DCR. Always consider the losses
associated with the DCR and its effect on the total
converter efficiency when selecting an inductor.
The 4.7µH CDRH3D16 series inductor selected
from Sumida has a 105mΩDCR and a 900mA DC
current rating. At full load, the inductor DC loss is
17mW which gives a 2.8% loss in efficiency for a
400mA, 1.5V output.
Input Capacitor
Select a 4.7µF to 10µF X7R or X5R ceramic capac-
itor for the input. To estimate the required input
capacitor size, determine the acceptable input rip-
ple level (VPP) and solve for C. The calculated
value varies with input voltage and is a maximum
when VIN is double the output voltage.
Always examine the ceramic capacitor DC voltage
coefficient characteristics when selecting the prop-
er value. For example, the capacitance of a 10µF,
6.3V, X5R ceramic capacitor with 5.0V DC applied
is actually about 6µF.
The maximum input capacitor RMS current is:
The input capacitor RMS ripple current varies with
the input and output voltage and will always be less
than or equal to half of the total DC load current.
for VIN = 2 x VOBUCK
The term appears in both the
input voltage ripple and input capacitor RMS cur-
rent equations and is a maximum when VOBUCK is
twice VIN. This is why the input voltage ripple and
the input capacitor RMS current ripple are a maxi-
mum at 50% duty cycle.
The input capacitor provides a low impedance loop
for the edges of pulsed current drawn by the
AAT2500. Low ESR/ESL X7R and X5R ceramic
capacitors are ideal for this function. To minimize
stray inductance, the cap acitor should be placed as
closely as possible to the IC. This keeps the high
frequency content of the input current localized,
minimizing EMI and input voltage ripple.
The proper placement of the input capacitor (C2)
can be seen in the evaluation board layout in
Figure 3.
A laboratory test set-up typically consists of two
long wires running from the bench power supply to
the evaluation board input voltage pins. The induc-
tance of these wires, along with the low-ESR
ceramic input capacitor, can create a high Q net-
work that may affect converter performance. This
problem often becomes apparent in the form of
excessive ringing in the output voltage during load
transients. Errors in the loop phase and gain meas-
urements can also result.
Since the inductance of a short PCB trace feeding
the input voltage is significantly lower than the
power leads from the bench power supply, most
applications do not exhibit this problem.
⎛⎞
· 1 -
⎝⎠
VOBUCK
VIN
VOBUCK
VIN
IOBUCK
RMS(MAX)
I2
=
⎛⎞
· 1 - = D · (1 - D) = 0.52 =
⎝⎠
VOBUCK
VIN
VOBUCK
VIN
1
2
⎛⎞
IRMS = IOBUCK · · 1 -
⎝⎠
VOBUCK
VIN
VOBUCK
VIN
CIN(MIN) = 1
⎛⎞
- ESR · 4 · FS
⎝⎠
VPP
IOBUCK
⎛⎞
· 1 - = for VIN = 2 × VOBUCK
⎝⎠
VOBUCK
VIN
VOBUCK
VIN
1
4
⎛⎞
· 1 -
⎝⎠
VOBUCK
VIN
CIN =
VOBUCK
VIN
⎛⎞
- ESR · FS
⎝⎠
VPP
IOBUCK
In applications where the input power source lead
inductance cannot be reduced to a level that does
not affect the converter performance, a high ESR
tantalum or aluminum electrolytic should be placed
in parallel with the low ESR, ESL bypass ceramic.
This dampens the high Q network and stabilizes
the system.
Output Capacitor
The output capacitor limits the output ripple and
provides holdup during large load transitions. A
4.7µF to 10µF X5R or X7R ceramic capacitor typi-
cally provides sufficient bulk capacitance to stabi-
lize the output during large load transitions and has
the ESR and ESL characteristics necessary for low
output ripple.
The output voltage droop due to a load transient is
dominated by the capacitance of the ceramic out-
put capacitor. During a step increase in load cur-
rent, the ceramic output capacitor alone supplies
the load current until the loop responds. Within two
or three switching cycles, the loop responds and
the inductor current increases to match the load
current demand. The relationship of the output volt-
age droop during the three switching cycles to the
output capacitance can be estimated by:
Once the average inductor current increases to the
DC load level, the output voltage recovers. The
above equation establishes a limit on the minimum
value for the output capacitor with respect to load
transients.
The internal voltage loop compensation also limits
the minimum output capacitor value to 4.7µF. This
is due to its effect on the loop crossover frequency
(bandwidth), phase margin, and gain margin.
Increased output capacitance will reduce the
crossover frequency with greater phase margin.
The maximum output capacitor RMS ripple current
is given by:
Dissipation due to the RMS current in the ceramic
output capacitor ESR is typically minimal, resulting in
less than a few degrees rise in hot-spot temperature.
Adjustable Output Resistor Selection
For applications requiring an adjustable output volt-
age, the 0.6V version can be externally pro-
grammed. Resistors R1 and R2 of Figure 5 program
the output to regulate at a voltage higher than 0.6V.
To limit the bias current required for the external
feedback resistor string while maintaining good
noise immunity, the minimum suggested value for
1
23
VOUT · (VIN(MAX) - VOUT)
RMS(MAX)
IL · F · VIN(MAX)
=·
·
COUT =
3 · ∆ILOAD
VDROOP · FS
AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 17
Figure 3: AAT2500 Evaluation Board Top Side. Figure 4: AAT2500 Evaluation Board
Bottom Side.
AAT2500
1MHz Step-Down Converter/LDO Regulator
18 2500.2005.08.1.9
R2 is 59kΩ. Although a larger value will further
reduce quiescent current, it will also increase the
impedance of the feedback node, making it more
sensitive to external noise and interference. Table 2
summarizes the resistor values for various output
voltages with R2 set to either 59kΩfor good noise
immunity or 221kΩfor reduced no load input current.
The adjustable version of the AAT2500, combined
with an external feedforward capacitor (C8 in
Figures 2 and 5), delivers enhanced transient
response for extreme pulsed load applications. The
addition of the feedforward capacitor typically
requires a larger output capacitor C1 for stability. Table 2: Adjustable Resistor Values For Use
With 0.6V Step-Down Converter.
R2 = 59kΩΩR2 = 221kΩΩ
VOUT (V) R1 (kΩΩ) R1 (kΩΩ)
0.8 19.6 75
0.9 29.4 113
1.0 39.2 150
1.1 49.9 187
1.2 59.0 221
1.3 68.1 261
1.4 78.7 301
1.5 88.7 332
1.8 118 442
1.85 124 464
2.0 137 523
2.5 187 715
⎛⎞
⎝⎠
R1 = -1 · R2 = - 1 · 59kΩ = 88.5kΩ
VOUT
VREF
⎛⎞
⎝⎠
1.5V
0.6V
Figure 5: AAT2500 Evaluation Board Schematic.
1. For step-down converter, enhanced transient configuration C8 = 100pF and C1 = 10uF.
Table 3
L1
4.7µF1
C1
10µF
C2
GND
VIN1
1
2
3
Buck Enable
LX1
GND
Table 3
R1
59k
R2
PGND
1
LX
2
VP
3
VCC
4ENLDO 9
EN 10
FB 11
SGND 12
IN
5
OUT
6
GND 8
BYP 7
AAT2500
U1
4.7µF
C4
10µF
C3
10nF
C5 1
2
3
LDO Enable
VOUTLDO
VOUTBUCK
1
2
3
LDO Input
0.01µF
C7
C81
n/a
C9
Thermal Calculations
There are three types of losses associated with the
AAT2500 step-down converter: switching losses,
conduction losses, and quiescent current losses.
Conduction losses are associated with the RDS(ON)
characteristics of the power output switching
devices. Switching losses are dominated by the
gate charge of the power output switching devices.
At full load, assuming continuous conduction mode
(CCM), a simplified form of the step-down convert-
er and LDO losses is given by:
IQBUCK is the step-down converter quiescent cur-
rent and IQLDO is the LDO quiescent current. The
term tsw is used to estimate the full load step-down
converter switching losses.
For the condition where the buck converter is in
dropout at 100% duty cycle, the total device dissi-
pation reduces to:
Since RDS(ON), quiescent current, and switching
losses all vary with input voltage, the total losses
should be investigated over the complete input
voltage range.
Given the total losses, the maximum junction tem-
perature can be derived from the θJA for the
TDFN33-12 package which is 50°C/W.
PCB Layout
The following guidelines should be used to ensure
a proper layout.
1. The input capacitor C2 should connect as
closely as possible to VP and PGND, as shown
in Figure 4.
2. The output capacitor and inductor should be
connected as closely as possible. The connec-
tion of the inductor to the LX pin should also be
as short as possible.
3. The feedback trace should be separate from
any power trace and connect as closely as
possible to the load point. Sensing along a
high-current load trace will degrade DC load
regulation. If external feedback resistors are
used, they should be placed as closely as pos-
sible to the FB pin. This prevents noise from
being coupled into the high impedance feed-
back node.
4. The resistance of the trace from the load return
to GND should be kept to a minimum. This will
help to minimize any error in DC regulation due
to differences in the potential of the internal sig-
nal ground and the power ground.
5. For good thermal coupling, PCB vias are
required from the pad for the TDFN paddle to the
ground plane. The via diameter should be 0.3mm
to 0.33mm and positioned on a 1.2mm grid.
6. LDO bypass capacitor (C5) should be connected
directly between pins 7 (BYP) and 8 (GND)
TJ(MAX) = PTOTAL · ΘJA + TAMB
PTOTAL = IOBUCK
2 · RDSON(HS) + IOLDO · (VIN - VOLDO)
+ (IQBUCK + IQLDO) · VIN
PTOTAL
IOBUCK
2 · (RDSON(HS) · VOBUCK + RDSON(LS) · [VIN - VOBUCK])
VIN
=
+ (tsw · F · IOBUCK + IQBUCK + IQLDO) · VIN + IOLDO · (VIN - VOLDO)
AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 19
Step-Down Converter Design Example
Specifications
VOBUCK = 1.8V @ 400mA (adjustable using 0.6V version), Pulsed Load ∆ILOAD = 300mA
VOLDO = 3.3V @ 300mA
VIN = 2.7V to 4.2V (3.6V nominal)
FS= 1.0MHz
TAMB = 85°C
1.8V Buck Output Inductor
(see Table 1)
For Sumida inductor CDRH3D16, 4.7µH, DCR = 105mΩ.
1.8V Output Capacitor
VDROOP = 0.2V
1
23
1 1.8V · (4.2V - 1.8V)
4.7µH · 1.0MHz · 4.2V
23
RMS
IL1 · F · VIN(MAX)
= ·
·
3 · ∆ILOAD
VDROOP · FS
3 · 0.3A
0.2V · 1MHz
COUT = = = 4.5µF
· = 63mArms
·
(VOBUCK) · (VIN(MAX) - VOBUCK)=
Pesr = esr · IRMS2 = 5mΩ · (63mA)2 = 20µW
V
OBUCK
V
OBUCK
1.8
V
1.8V
∆I
L1
=
⋅ 1 - = ⋅ 1 - = 218mA
L1 ⋅ F
V
IN
4.7µH ⋅ 1.0MHz
4.2V
I
PKL1
= I
OBUCK
+ ∆I
L1
= 0.4A + 0.11A = 0.51A
2
P
L1
= I
OBUCK2
⋅ DCR = 0.4A
2
⋅ 105mΩ = 17mW
⎛
⎝⎞
⎠
⎛
⎝⎞
⎠
L1 = 3 ⋅ V
O2
= 3 ⋅ 1.8V = 5.4µH
µsec
A
µsec
A
AAT2500
1MHz Step-Down Converter/LDO Regulator
20 2500.2005.08.1.9
Input Capacitor
Input Ripple VPP = 25mV
AAT2500 Losses
PTOTAL
+ (tsw · F · IOBUCK + IQBUCK + IQLDO) · VIN + (VIN - VLDO) · ILDO
IOBUCK
2 · (RDSON(HS) · VOBUCK + RDSON(LS) · [VIN - VOBUCK])
VIN
=
=
+ (5ns · 1.0MHz · 0.4A + 50µA +125µA) · 4.2V + (4.2V - 3.3V) · 0.3A = 392mW
0.42 · (0.725Ω · 1.8V + 0.7Ω · [4.2V - 1.8V])
4.2V
IOBUCK
RMS
I
P = esr · IRMS
2 = 5mΩ · (0.2A)2 = 0.2mW
2
= = 0.2Arms
CIN = = = 4.75µF
1
⎛⎞
- ESR · 4 · FS
⎝⎠
VPP
IOBUCK
1
⎛⎞
- 5mΩ · 4 · 1MHz
⎝⎠
25mV
0.4A
AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 21
Table 3: Evaluation Board Component Values.
Table 4: Typical Surface Mount Inductors.
Inductance Max DC DCR Size (mm)
Manufacturer Part Number (µH) Current (A) (ΩΩ) LxWxH Type
Sumida CDRH3D16-4R7 4.7 0.90 0.11 3.8x3.8x1.8 Shielded
Sumida CDRH3D16-100 10 0.55 0.21 3.8x3.8x1.8 Shielded
MuRata LQH32CN4R7M23 4.7 0.45 0.20 2.5x3.2x2.0 Non-Shielded
MuRata LQH32CN4R7M33 4.7 0.65 0.15 2.5x3.2x2.0 Non-Shielded
MuRata LQH32CN4R7M53 4.7 0.65 0.15 2.5x3.2x1.55 Non-Shielded
Coilcraft LPO6610-472 4.7 1.10 0.20 5.5x6.6x1.0 1mm
Coilcraft LPO3310-472 4.7 0.80 0.27 3.3x3.3x1.0 1mm
Coiltronics SDRC10-4R7 4.7 1.53 0.117 4.5x3.6x1.0 1mm Shielded
Coiltronics SDR10-4R7 4.7 1.30 0.122 5.7x4.4x1.0 1mm Shielded
Coiltronics SD3118-4R7 4.7 0.98 0.122 3.1x3.1x1.85 Shielded
Coiltronics SD18-4R7 4.7 1.77 0.082 5.2x5.2x1.8 Shielded
VOUT (V) R1 (kΩΩ) R1 (kΩΩ) L1 (µH)
Adjustable Version R2 = 59kΩΩR2 = 221kΩΩ11
(0.6V device)
0.8 19.6 75.0 4.7
0.9 29.4 113 4.7
1.0 39.2 150 4.7
1.1 49.9 187 4.7
1.2 59.0 221 4.7
1.3 68.1 261 4.7
1.4 78.7 301 4.7
1.5 88.7 332 4.7
1.8 118 442 4.7
1.85 124 464 4.7
2.0 137 523 4.7 or 6.8
2.5 187 715 10
VOUT (V) R1 (kΩΩ) L1 (µH)
Fixed Version R2 Not Used
0.6-3.3V 0 4.7
AAT2500
1MHz Step-Down Converter/LDO Regulator
22 2500.2005.08.1.9
1. For reduced quiescent current R2 = 221kΩ.
Table 5: Surface Mount Capacitors.
Manufacturer Part Number Value Voltage Temp. Co. Case
MuRata GRM21BR61A475KA73L 4.7µF 10V X5R 0805
MuRata GRM18BR60J475KE19D 4.7µF 6.3V X5R 0603
MuRata GRM21BR60J106KE19 10µF 6.3V X5R 0805
MuRata GRM21BR60J226ME39 22µF 6.3V X5R 0805
AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 23
Ordering Information
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means
semiconductor products that are in compliance with current RoHS standards, including
the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more
information, please visit our website at http://www.analogictech.com/pbfree.
Voltage
Package Buck Converter LDO Marking1Part Number (Tape and Reel)2
TDFN33-12 Adj - 0.6V 3.3V NZXYY AAT2500IWP-AW-T1
TDFN33-12 Adj - 0.6V 3.0V NYXYY AAT2500IWP-AT-T1
TDFN33-12 Adj - 0.6V 2.8V OAXYY AAT2500IWP-AQ-T1
TDFN33-12 Adj - 0.6V 2.7V ORXYY AAT2500IWP-AP-T1
TDFN33-12 Adj - 0.6V 2.5V OOXYY AAT2500IWP-AN-T1
TDFN33-12 Adj - 0.6V 1.8V ONXYY AAT2500IWP-AI-T1
TDFN33-12 Adj - 0.6V 1.5V OMXYY AAT2500IWP-AG-T1
TDFN33-12 1.2V 3.0V OWXYY AAT2500IWP-ET-T1
TDFN33-12 1.8V 2.7V PFXYY AAT2500IWP-IP-T1
AAT2500
1MHz Step-Down Converter/LDO Regulator
24 2500.2005.08.1.9
Legend
Voltage Code
Adjustable A
(0.6V)
1.2 E
1.5 G
1.8 I
1.9 Y
2.5 N
2.6 O
2.7 P
2.8 Q
2.85 R
2.9 S
3.0 T
3.3 W
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
Package Information
TDFN33-12
Top View Bottom View
Detail "B"
Detail "A"
Side View
3.00 ± 0.05
Index Area
(D/2 x E/2)
Detail "A"
Detail "B"
1.70 ± 0.05
3.00 ± 0.05
0.05 ± 0.05
0.229 ± 0.051
7.5° ± 7.5°
2.40 ± 0.05
0.16
Pin 1 Indicator
(optional)
0.375 ± 0.125
0.3 ± 0.10
0.45 ± 0.050.23 ± 0.05
0.075 ± 0.075
0.1 REF
0.8 + 0.05
-0.20
Option A:
C0.30 (4x) max
Chamfered corner
Option B:
R0.30 (4x) max
Round corner
AAT2500
1MHz Step-Down Converter/LDO Regulator
2500.2005.08.1.9 25
AAT2500
1MHz Step-Down Converter/LDO Regulator
26 2500.2005.08.1.9
Advanced Analogic Technologies, Inc.
830 E. Arques Avenue, Sunnyvale, CA 94085
Phone (408) 737-4600
Fax (408) 737-4611
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