Pin name

Pin location

Pin function

CLAMP1

C8

Auxiliary modulation switches connection: capacitors between CLAMP1 and AC1 and

between CLAMP2 and AC2 are used to implement additional ASK modulation. These

pins are optionally used, in conjunction with COMM1 and COMM2 pins, to modify the

ASK modulation index in specific operating conditions.

CLAMP2

C7

VRECT

A4, A5, B4,

B5, C3

Synchronous rectifier output and input for the main LDO linear regulator. A suitable

capacitor between these pins and VSSP ensures residual AC ripple filtering and

energy storage for proper load transient response.

VS

F1

Reserved: this pin must be left floating.

DFT

G1

Reserved: this pin must be connected to ground.

BOOT_SEL

J5

Reserved: this pin must be connected to ground.

NTC

F8

Coil temperature sensing input: this pin is connected to the center tap of a resistor

divider having an NTC in the low-side position. If this function is not used, the pin

must be pulled-up to V18 through a 10 kΩ resistor to prevent triggering the coil

over-temperature protection.

COMM1

D8

Modulation switches connection: capacitors between COMM1 and AC1 pin and

between COMM2 and AC2 pin are used to implement ASK modulation.

COMM2

D7

VOUT

D2, E1, E2,

E3, F2

Main LDO linear regulator output voltage. Connect a suitable filtering capacitor

between these pins and VSSA to ensure stable operation and proper load transient

response in all operating conditions.

V1V8

G5, G8

1.8V LDO output and supply rail for the digital core, the ADC and the analog circuitry.

Connect a 1 μF filtering capacitor between this pin and ground.

V5V0

F7, E6

5V LDO output and supply rail for the auxiliary circuitry. Connect a 1 μF filtering

capacitor between this pin and ground.

RSTB

J6

Chip-reset input. If set low, the internal digital core is reset. This pin is eventually used

by the host controller to control the power transfer process. Connect to V1V8 pin if not

used.

IEXT

C2

Internal pull-down switch for resisitive (dissipative) over-voltage protection: a resistor

with adequate power dissipation capability must be connected between this pin and

VRECT to damp excessive voltage developing at the output of the rectifier.

VGATE

D1

Gate driver output for the optional VRECT discharging transistor. This pin goes high

when the voltage drop across the main LDO (VVRECT – VVOUT) exceeds the

programmed threshold.

SCL

H8

I2C bus, clock line input. A pull-up resistor to the supply rail of the host controller is

required to ensure correct digital levels.

SDA

J8

I2C bus, data line I/O. A pull-up resistor to the supply rail of the host controller is

required to ensure correct digital levels.

NC

C6, D6

Reserved: this pin must be connected to ground or left floating.

GPIO0

H2

Programmable general-purpose I/Os: the function of these pins depends on the

configuration of the device.

GPIO1

H1

GPIO2

J4

GPIO3

J3

GPIO4

J2

GPIO5

J1

INTB

J7

Interrupt output (active low). Programmable open-drain output used to generate an

interrupt on specific events for the host controller. Also used as auxiliary control signal

during OTP flash.

STWLC68

Device pinout

DS13131 - Rev 3

page 5/32