Application Circuits

Note: Substrate connect to VDD

BZ1 and BZ2 are connected to an external buzzer to generate sounds.

LOWC is connected to an external resistor for adjusting the detector level of a low voltage de-

tector. Open the pin when not in use.

OSCI, OSCO are connected to an external resistor, and form an RC oscillator with a built-in

capacitor for SYSTEM clock (=32kHz)

RS, RF, SC constitute an alternating RC oscillator, which allows one oscillator, namely RS or

RF, active at a time.

REF (reference resistor) is a resistor value equal to 503ET, sensor is value in 37.0 °C or 98.6 °F.

SENSOR is a 503ET thermistor.

HT7500

7

August 8, 2000

SE N S O R

RE F

400k W

2200 ~ 270 0pF

0. 02 2 m F

0. 02 2 m F

To LC D

0 6 %#

BZ 1

BZ 2

1. 5V

Ba t t e r y

B u zze r

LOW C

VS S

SC

RF

RS

VD D

PS W

TE S T 2

CLF H

OS C I

OS C O

C 512

CA P

VE E

SD 1

SC 1 ~ 3

SB 1 ~ 3

SA 1 ~ 3

CO M 3

CO M 2

CO M 1