Holtek Semiconductor Inc HT7501 Datasheet

Features

•

Single-chip CMOS construction

•

Single 1.5V battery operation

•

Measurement range: +32.00°C~+43.00°C
Measurement accuracy:
Resolution: 0.01

•

Auto self-test

°C

±0.1°C

General Description

The HT7501 is a CMOS digital clinical ther­mometer IC for measuring body temperature
from 32.00
self-test, auto power off and last time measured

°C~43.00°C. It also provides alarm,

Block Diagram

HT7501

Clinic a l Thermom e ter

•

Alarm warning for fever

•

Highest temperature hold

•

Auto power off after 8 min 40 sec

•

One-key input switch for ON/OFF

•

Displays last time measured te mperatur e

temperature functions. The other electronic
components a re LCD displa y, thermister, 1.5V
battery, ON/OFF switch, buzzer, resistors and
capacitors.

1 8th Feb ’99

Pad Assignment

HT7501

Chip size: 121 × 124 (mil)

* The IC substrate should be connected to VDD in the PCB layout artwork.

2

Pad Coordinates Unit: mil

Pad No. X Y Pad No. X Y

1 –54.78 54.10 19 20.27 –56.53
2 –54.78 46.45 20 54.78 –56.53
3 –54.78 39.10 21 54.78 –49.30
4 –54.78 31.45 22 54.78 –37.99
5 –54.78 24.10 23 54.78 –25.58
6 –54.78 16.45 24 54.78 –1.02
7 –54.78 9.10 25 54.02 8.50
8 –54.78 1.45 26 54.02 15.13

9 –54.78 –5.91 27 54.02 27.11
10 –54.78 –13.56 28 51.13 55.85
11 –52.53 –56.53 29 44.50 55.85
12 –44.46 –56.53 30 37.87 55.85
13 –37.10 –56.53 31 31.24 55.85
14 –29.88 –56.53 32 18.02 56.61
15 –22.82 –56.53 33 1.95 56.61
16 –5.31 –56.53 34 –17.34 56.61
17 5.40 –56.53 35 –23.97 56.61
18 13.64 –56.53 36 –40.97 56.61

2 8th Feb ’99

HT7501

Pad Description

Pad No. Pad Name I/O Function

1~3 SA1~SA3 O LCD segment drive
4~6 SB1~SB3 O LCD segment drive
7~19 SC1~SC3 O LCD segment drive
10~12 SD1~SD3 O LCD segment drive
13 SE1 O LCD segment drive
14 VEE O Generate negative voltage (–1.5V)
15 CAP O For negative voltage, NMOS output
16 C512 O For negative voltage, inverter output
17 TV B Test pin for IC
18 TEST1 I Test pin for IC
19 LOWC B For the supply voltage detector. Open the pin when not in use.
20 VSS I Power supply GND
21 SC B Common point, NMOS open drain
22 RF O Connect reference resistor, PMOS open drain
23 RS O Connect sensor resistor, PMOS open drain
24 VDD I Positive power supply
25 PSW I Pull low input pin, push switch to turn the power on or off

Pull low test pin, for productio n test, floating LCD displays

26 TEST2 I

27 ML I Connect to VDD for memory function, otherwise floating.
28 FEVL I Floating with fever function, otherwise connect to VDD.
29 S804KL I Floating buzzer is 4kHz, connect to VDD if buzzer is 8kHz.
30 OSCI I For system oscillator in
31 OSCO O For system oscillator out
32 BZ1 O Buzzer output 1
33 BZ2 O Buzzer output 2
34~36 COM1~COM3 O LCD backplane drive, 3-level voltage out

the real time value , when connected to VDD, LCD disp lays
the highest value.

3 8th Feb ’99