RT9535
Functional Pin Description
Pin No.
Pin Name
Pin Function
Negative Terminal to Sense Input Current. A filter is needed to filter out the
500kHz switching noise.
1
ACN
2
3
ACP
Positive Terminal to Sense Input Current.
ACDRV
Drive Signal for the Gate of Input Power PFET.
Enable Control Input (Active High). It must be connected to a logical voltage or
pulled up to VIN with a 100k resistor.
4
5
6
7
EN
Soft-Start Control Input. SS controls the soft-start time. Connect a capacitor
from SS pin to GND to set the soft-start time.
SS
Charge Current Setting and System Loop Compensation Pin. Connect a
resistor from this pin to ground to set the charge current.
ISET
VC
Control Signal of the Inner Loop of the Current Mode PWM. A capacitor of at
least 0.1F with a serial resistor to GND filters out the current ripple.
Flag to Indicate Charge Completion. It turns to logical high when the charge
current drops blew 17% of the setting charge current. A 0.1F capacitor from
STATUS to ground is needed to filter the sampled charge current ripple.
8
STATUS
9
NTC
FBR
Input for an external NTC thermistor for battery temperature monitoring.
Negative Terminal of External Resistor Divider for Battery Voltage Feedback.
10
Battery Voltage Feedback. Using an external resistor divider to set battery full
charge voltage.
11
12
13
VFB
To supply the current sense amplifier CAfor 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.
VHH
BATT
Battery Voltage Sensing Input. A 10F or larger X5R ceramic capacitor is
recommended for filtering charge current ripple and stability purpose.
14
15
16
SNSL
SNSH
PGND
Negative Terminal for Sensing Charge Current.
Positive Terminal for Sensing Charge Current.
Power Ground.
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.
17, 18
19, 20
SW
Drain of Internal High-Side power N-MOSFET Switch. Connect a low ESR
capacitor of 10F or higher from this pin to ground for good bypass.
HSD
BOOT
VIN
Bootstrap Supply for the High-Side Power Switch Gate Driver and Control
Circuitry. In normal operation, VBOOT ≈ VSW + 5V.
21
22
23
24
Input Power Supply. Connect a low ESR capacitor of 10F or higher from this
pin to ground for good bypass.
Output of Internal 5V LDO. Connect a 1F ceramic capacitor from this pin to
GND for stability.
V5V
Analog Ground. Layout input capacitor and V5V capacitor to this pin as close
as possible.
GND
GND
25
Exposed Pad. Connect the exposed pad to GND.
(Exposed Pad)
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is a registered trademark of Richtek Technology Corporation.
DS9535-04 February 2016
www.richtek.com
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