RTQ2521

2

DSQ2521-01 May 2019

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Functional Pin Description

Pin No.

Pin Name

Pin Function

1

VOUT

LDO output pins. A 4.7

F or greater of capacitance is required for stability.

Place the output capacitor as close to the device as possible and minimize

the impedance between VOUT pin to load.

2

FB

Feedback voltage input. This pin is used to set the desired output voltage

via an external resistive divider. The feedback reference voltage is 0.8V

typically.

3,

9 (Exposed Pad)

GND

Ground. The exposed pad must be soldered to a large PCB and connected

to GND for maximum the power dissipation.

4

PGOOD

Power good indicator output. An open-drain output and active high when the

output voltage reaches 88% of the target. The pin is pulled to ground when

the output voltage is lower than its specified threshold, EN shutdown, OCP

and OTP.

5

NC

No internal connection. Leave these pins floating doesn’t affect the chip

functionality. By connecting these pins to GND, design engineers could

extend the GND copper coverage on the PCB top layer to enhance the

thermal convection.

6

NR/SS

Noise-reduction and soft-start pin. Decouple this pin to GND with an external

capacitor CNR/SS can not only reduce output noise to very low levels but also

slow down the VOUT rise like a soft-start behavior. For low noise

applications, a 10nF to 1

F CNR/SS is suggested.

7

EN

Enable control input. Connecting this pin to logic high enables the regulator

or driving this pin low puts it into shutdown mode. The device can have VIN

and VEN sequenced in any order without causing damage to the device.

However, for the soft-start function to work as intended, certain sequencing

rules must be applied. Enabling the device after VIN are present is preferred.

8

VIN

Supply input. A minimum of 10

F ceramic capacitor or greater of

capacitance is required and should be placed as close as possible to this

pin for better noise rejection.