RT9535B

Copyright © 2016 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS9535B-04

February

2016

www.richtek.com

3

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

ACN

Negative Terminal to Sense Input Current. A filter is needed to filter out the

500kHz switching noise.

2

ACP

Positive Terminal to Sense Input Current.

3

ACDRV

Drive Signal for the Gate of Input Power PFET.

4

EN

Enable Control Input (Active High). It must be connected to a logical voltage or

pulled up to VIN with a 100k

 resistor.

5

SS

Soft-Start Control Input. SS controls the soft-start time. Connect a capacitor

from SS pin to GND to set the soft-start time.

6

ISET

Charge Current Setting and System Loop Compensation Pin. Connect a

resistor from this pin to ground to set the charge current.

7

VC

Control Signal of the Inner Loop of the Current Mode PWM. A capacitor of at

least 0.1

F with a serial resistor to GND filters out the current ripple.

8

STATUS

Flag to Indicate Charge Completion. It turns to logical high when the charge

current drops blew 17% of the setting charge current. A 0.1

F capacitor from

STATUS to ground is needed to filter the sampled charge current ripple.

9

NTC

Input for an external NTC thermistor for battery temperature monitoring.

10

NC

No Internal Connection.

11

VFB

Battery Voltage Feedback. Using an external resistor divider to set battery full

charge voltage.

12

VHH

To supply the current sense amplifier CA for very low dropout condition. It must

be connected as shown in the typical application circuit or connected to VIN if

VIN is always larger than BATT by at least 1.8V.

13

BATT

Battery Voltage Sensing Input. A 10

F or larger X5R ceramic capacitor is

recommended for filtering charge current ripple and stability purpose.

14

SNSL

Negative Terminal for Sensing Charge Current.

15

SNSH

Positive Terminal for Sensing Charge Current.

16

PGND

Power Ground.

17, 18

SW

Switch Node. This pin switches between ground and VIN with high dv/dt rates.

Care needs to be taken in the PCB layout to keep this node from coupling to

other sensitive nodes.

19, 20

HSD

Drain of Internal High-Side power N-MOSFET Switch. Connect a low ESR

capacitor of 10

F or higher from this pin to ground for good bypass.

21

BOOT

Bootstrap Supply for the High-Side Power Switch Gate Driver and Control

22

VIN

Input Power Supply. Connect a low ESR capacitor of 10

F or higher from this

pin to ground for good bypass.

23

V5V

Output of Internal 5V LDO. Connect a 1

F ceramic capacitor from this pin to

GND for stability.

24

GND

Analog Ground. Layout input capacitor and V5V capacitor to this pin as close

as possible.

25

(Exposed Pad)

GND

Exposed Pad. Connect the exposed pad to GND.