ADP1148 Ver la hoja de datos (PDF) - Analog Devices

Número de pieza

componentes Descripción

Fabricante

ADP1148

High Efficiency Synchronous Step-Down Switching Regulators

Analog Devices 

ADP1148, ADP1148-3.3, ADP1148-5

PIN FUNCTION DESCRIPTIONS

Pin #

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Mnemonic

Function

P-Channel Drive High Current Gate Drive for Top P-Channel MOSFET. The voltage swing at Pin 4 is from VIN to

ground.

NC

No Connection.

VIN

CT

Int VCC

Input Voltage.

External Capacitor CT from Pin 4 to Ground Sets the Operating Frequency. The frequency is also

dependent on the ratio VOUT/VIN.

Internal Supply Voltage, Nominally 3.3 V. Must be decoupled to signal ground. Do not externally load

this pin.

ITH

Sense–

Error Amplifier Decoupling Point. The current comparator threshold increases with the Pin 7 voltage.

Connects to internal resistive divider that sets the output voltage in ADP1148-3.3 and ADP1148-5

versions. Pin 7 is also the (–) input for the current comparator.

Sense+

VFB

The (+) Input for the Current Comparator. A built-in offset between Pins 7 and 8, in conjunction with

RSENSE, sets the current trip threshold.

For the ADP1148 adjustable version, Pin 9 serves as the feedback pin from an external resistive divider

used to set the output voltage. On ADP1148-3.3 and ADP1148-5 versions, this pin is not used.

Shutdown

Taking Pin 10 of the ADP1148, ADP1148-3.3 or ADP1148-5 high holds both MOSFETs off. Must be

at ground potential for normal operation.

Signal GND

Power GND

NC

Small Signal Ground. Must be routed separately from other grounds to the (–) terminal of COUT.

Driver Power Ground. Connects to source of N-channel MOSFET and the (–) terminal of CIN.

No Connection.

N-Channel Drive High Current Drive for bottom N-channel MOSFET. The voltage swing at Pin 13 is from ground to

VIN.

PIN CONFIGURATIONS

14-Lead Plastic DIP

14-Lead Plastic SO

P-DRIVE 1

14 N-DRIVE

NC 2

13 NC

VIN 3 ADP1148 12 POWER GND

CT 4 TOP VIEW 11 SIGNAL GND

(Not to Scale)

INT VCC 5

10 SHUTDOWN

ITH 6

9 VFB*

SENSE(–) 7

8 SENSE(+)

NC = NO CONNECT

*FIXED OUTPUT VERSIONS = SD1

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily

accumulate on the human body and test equipment and can discharge without detection. Although

the ADP1148, ADP1148-3.3, ADP1148-5 feature proprietary ESD protection circuitry, permanent

damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper

ESD precautions are recommended to avoid performance degradation or loss of functionality.

WARNING!

ESD SENSITIVE DEVICE

–4–

REV. A

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