1

2

3

4

5

6

7

8

20

19

18

17

16

15

14

13

SYNC

SS/TRK

EN

AVIN

PVIN

PVIN

PVIN

PGND

SW

SW

SW

SW

AGND

FB

COMP

PGOOD

EP

PGND

PGND

12

11 SW

9

10

SW

LM21215A

www.ti.com

SNOSB87C – MARCH 2011 – REVISED JANUARY 2016

5 Pin Configuration and Functions

PWP Package

20-Pin HTSSOP With Exposed Thermal Pad

Top View

Pin Functions

PIN

DESCRIPTION

NO.

NAME

Frequency synchronization input pin. Applying a clock signal to this pin forces the device to switch

1

SYNC

I

at the clock frequency. If left unconnected, the frequency defaults to 500 kHz.

Soft-start control pin. An internal 2-µA current source charges an external capacitor connected

2

SS/TRK

I

between this pin and AGND to set the output voltage ramp rate during startup. This pin can also be

used to configure the tracking feature.

Active high precision enable input. If not used, the EN pin can be left open, which will go high due to

3

EN

I

an internal pullup current source.

Analog input voltage supply that generates the internal bias. Connect PVIN to AVIN through a low

4

AVIN

P

pass RC filter to minimize the influence of input rail ripple and noise on the analog control circuitry.

Input voltage to the power switches inside the device. Connect these pins together at the device.

5–7

PVIN

P

Locate a low ESR input capacitance as close as possible to these pins.

8–10

PGND

G

Power ground pins for the internal power switches.

11–16

SW

P

Switch node pins. Tie these pins together locally and connect to the filter inductor.

17

PGOOD

O

Open-drain power good indicator.

18

COMP

O

Compensation pin is connected to the output of the voltage loop error amplifier.

19

FB

I

Feedback pin is connected to the inverting input of the voltage loop error amplifier.

20

AGND

G

Quiet analog ground for the internal reference and bias circuitry.

Exposed

Exposed metal pad on the underside of the package with an electrical and thermal connection to

EP

P

Pad

PGND. Connect this pad to the PC board ground plane to improve thermal dissipation.

(1)

P = Power, G = Ground, I = Input, O = Output.

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