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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201999B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 20, 2013

AAT1171

600mA Voltage-Scaling Step-Down Converter

for RF Power Amplifiers with Bypass Switch

DATA SHEET

Pin Descriptions

Pin #

Symbol

Function

TDFN33-12

WLCSP-12

1

N/A

N/C

Not connected.

2, 3

5, 9

VOUT

Feedback input pin. This pin is connected to the converter output. It is used to

complete the control loop, regulating the output voltage to the desired value.

When in bypass mode, a low resistance MOSFET is connected between this pin

and VIN.

4

7

VCC

Bias supply. Supply power for the internal circuitry. Connect to input power via

low pass filter with decoupling to AGND.

5

6

AGND

Analog ground. Connect the return of all small signal components to this pin.

6

1

DAC

Control voltage input from a DAC. Input voltage between 0.2V and 1.2V to con-

trol output voltage of the converter. Force pin to 1.3V for bypass switch enable.

7

2

EN

Enable DC/DC converter, active high.

8

3

BYPASS

Enable control to bypass the DC/DC converter when PA transmitting at full

power from low battery voltage. Active high.

9

4

MODE/SYNC

This pin is used to program the device between PWM and LL mode:

HIGH - PWM Mode Only

LOW - LL Mode: PWM operation for loads above 100mA and variable switching

frequency for loads below 100mA. Connecting the SYNC pin to the system clock

(19.8MHz) will override the internal clock and force the switching frequency to

the external clock frequency divided by 10.

10

12

VIN

Input supply voltage for the converter. Must be closely decoupled.

11

8, 11

PGND

Main power ground. Connect to the output and input capacitor return.

12

10

LX

Switching node. Connect the inductor to this pin. It is connected internally to

the drain of both low- and high-side MOSFETs.

EP

N/A

Exposed paddle (bottom). Connect to ground directly beneath the package.

Pin Configuration

TDFN33-12

WLCSP-5

(Top View)

(Top View)

N/C

VOUT

VOUT

1

VCC

AGND

DAC

LX

PGND

VIN

MODE/SYNC

BYPASS

EN

2

3

4

5

6

12

11

10

9

8

7

12

11

10

7

8

9

6

5

4

1

2

3

VIN

VCC

AGND

DAC

5: VOUT

2: EN

11: PGND

8: PGND

LX

VOUT

MODE/SYNC

BYPASS