AAT2500B Datasheet, PDF (2/21 Pages) Advanced Analogic Technologies – Adjustable 3-Channel Regulator

SystemPower^TM
PRODUCT DATASHEET
AAT2500B
Adjustable 3-Channel Regulator
Pin Descriptions
Pin #
1
2
3
4
5
6
7
8, 9
10
11, 12
13
14
15
16
17
18
19
20
EP
Symbol
FBB
ENA
ENB
SYNC
FB
AGND
PGND
LX
VP
N/C
VIN
EN
POK
FBA
OUTA
VLDOA
VLDOB
OUTB
Function
Feedback input pin for LDOB. This pin is connected to OUTB. It is used to see the output of LDOB to regulate
to the desired value via an external resistor divider. For fixed versions, short FBB to OUTB.
Enable pin for LDOA. When connected low, LDOA is disabled and consumes less than 1μA of current. When
connected high, normal operation.
Enable pin for LDOB. When connected low, LDOB is disabled and consumes less than 1μA of current. When
connected high, normal operation.
Oscillator synchronization pin for the step-down converter. The internal oscillator is disabled and the step-
down converter can be synchronized to an external clock applied to this pin.
Feedback input pin for the step-down converter. This pin is connected to the converter output. It is used to
see the output of the converter to regulate to the desired value via an external resistor divider.
Ground connection pin.
Main power ground return pin for the step-down converter. Connect to the output and input capacitor return.
Connect inductor to this pin. Switching node internally connected to the drain of both high- and low-side
MOSFETs.
Bias supply. Supply power for the internal circuitry. Connect to input power via low pass filter with decou-
pling to AGND.
Not connected.
Input supply voltage for the converter. Must be closely decoupled.
Enable for the step-down converter. A logic low disables the converter and it consumes less than 1μA of cur-
rent. A logic high enables normal operation.
Power-OK pin with open drain output. It is pulled low when the OUTA pin is outside the regulation window of
±10%. Place a pull-up resistor between POK and OUTA.
Feedback input pin for LDOA. This pin is connected to OUTA. It is used to see the output of LDOA to regulate
to the desired value via an external resistor divider. For fixed versions, short FBA to OUTA.
LDOA output pin; should be closely decoupled with a low-ESR ceramic capacitor.
Input voltage pin for linear regulator A; should be closely decoupled.
Input voltage pin for linear regulator B; should be closely decoupled.
LDOB output pin; should be closely decoupled with a low-ESR ceramic capacitor.
Exposed paddle; connect to ground directly beneath the package.
Pin Configuration
QFN34-20
(Top View)
FBB ¹
ENA ²
ENB ³
SYNC ⁴
FB ⁵
AGND ⁶
16 _FBA
15 _POK
14 _EN
13 _VIN
12 _N/C
11 _N/C
2
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2500B.2008.03.1.0