Pin Name

I/O

Options

Description

BZO

BZO

O

¾

High voltage buzzer complement output signals

VO

¾¾

LDO regulator output

VCC

¾¾

High voltage positive power supply for driving the VFD filament, F1O,

BZO and BZO outputs. An external 10uF capacitor is recommended to be

connected to ground on the PCB to reduce surge voltages.

VFD0~VFD23

O

¾

High voltage grid/segment output for VFD panel

RES

I

¾

Schmitt trigger reset input. Active low

VSS

¾¾

Negative power supply, ground

VDD

¾¾

Positive power supply

OSC1

OSC2

I

O

Crystal or RC

OSC1, OSC2 are connected to an RC network or Crystal determined by a

configuration option, for the internal system clock. In the case of the RC

oscillator, OSC2 can be used to monitor the system clock. Its frequency is

1/4 system clock.

Note:

1. *All pull-high resistors are controlled by an option bit.

2. Pin PB3~PB7 are five internal pins only and not bound out and its port control register must setup this pin

as an output.

3. PB3~PB7 individual pins can be selected to have a pull-high resistor.

Absolute Maximum Ratings

Storage Temperature ............................

-50°Cto125°C

Operating Temperature...........................

-40°Cto85°C

VCC Supply Voltage.....................................12V to 24V

-100mA

Total Power Dissipation .....................................500mW

Note: These are stress ratings only. Stresses exceeding the range specified under

²Absolute Maximum Ratings² 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.

D.C. Characteristics

Ta=25

°C

Symbol

Parameter

Test Conditions

Min.

Typ.

Max.

Unit

Conditions

Operating Voltage

¾¾

2.2

¾

5.5

V

3.3

¾

5.5

V

Operating Current

(Crystal OSC, RC OSC)

3V

¾

¾

12

mA

5V

¾¾

35

mA

Operating Current

(Crystal OSC, RC OSC)

5V

¾

48

mA

Standby Current

(WDT Enabled)

3V

¾

No load, system HALT

¾¾

5

mA

5V

¾¾

¾

10

mA

Standby Current

(WDT Disabled)

3V

¾

No load, system HALT

¾¾

1

mA

5V

¾¾

¾

2

mA

Input Low Voltage for I/O Ports,

TMR, INT0 and INT1

¾¾

¾

0

¾

V

HT45R35V

Rev. 1.00

4

January 15, 2009