Rev. 1.00

5

November 22, 2011

HT16C21

Pin Description

Pin Name

Type

Description

SDA

I/O

SCL

I

VDD

—

Positive power supply.

VSS

—

Negative power supply, ground.

VLCD

—

● One external resistor is connected between the VLCD pin and the VDD

pin to determine the bias voltage for the package with a VLCD pin.

Internal voltage adjustment function is disabled.

voltage. If the VLCD pin is used as voltage detection pin, an external

power supply should not be applied to the VLCD pin.

● An external MCU can detect the voltage of the VLCD pin and program the

internal voltage adjustment for the packages with a VLCD pin.

COM0~COM3

O

LCD common outputs.

COM4/SEG0~COM7/SEG3

O

LCD common/segment multiplexed driver outputs

SEG4~SEG19

O

LCD segment outputs.

Approximate Internal Connections

VDD

VSS

SCL, SDA (for schmit Trigger type)

Vselect-on

Vselect-off

COM0~COM7; SEG0~SEG19

Absolute Maximum Ratings

Storage temperature .......................................................................................................................-55°C to +150°C

Operating temperature .....................................................................................................................-40°C to +85°C

Note: These are stress ratings only. Stresses exceeding the range specified under "Absolute Maximum Ratings"

may cause substantial damage to the device. Functional operation of this device at other conditions beyond

those listed in the specification is not implied and prolonged exposure to extreme conditions may affect

device reliability.