IZ8005
1
CLINICAL THERMOMETER
General Description
The IZ8005 is a CMOS digital clinical thermometer IC for measuring body temperature from
32.00C~43.00C. It also provides alarm, self-test, auto power off and last time measured
temperature functions. The other electronic components are LCD display, thermister, 1.5V battery,
ON/OFF switch, buzzer, resistors and capacitors.
Features
Single-chip CMOS construction
Single 1.5V battery operation
Measurement range: +32.00C ~ +43.00C
Measurement accuracy: 0.1C
Resolution: 0.01C
Auto self-test
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 temperature
Block Diagram
IZ8005
2
Pad Assignment
37
Chip size: 1.97 x 2.12 mm
2
* The IC substrate should be connected to VDD in the PCB layout artwork.
IZ8005
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Pad Description
Pad
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
26 TEST2
I
Pull low test pin, for production test, floating LCD displays the real time
value, when connected to VDD, LCD displays the highest value.
27
INIT
I
Test pin for IC
28
ML
I
Connect to VDD for memory function, otherwise floating.
29
FEVL
I
Floating with fever function, otherwise connect to VDD.
30
S804KL
I
Floating buzzer is 4kHz, connect to VDD if buzzer is 8kHz.
31
OSCI
I
For system oscillator in
32
OSCO
O
For system oscillator out
33
BZ1
O
Buzzer output 1
34
BZ2
O
Buzzer output 2
35~37
COM1~COM3
O
LCD backplane drive, 3-level voltage out
Absolute Maximum Ratings
Supply voltage.......................0V to 2.0V
Input voltage.............. VSS-0.5V to
VDD+0.5V
Operation Temperature.......-20C to +75C
Storage
Temperature.............-55Cto
+125C
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.
IZ8005
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Electrical Characteristics
Symbol Parameter
Test
Conditions
Min. Typ. Max. Unit
V
DD
Operating
Voltage
--
1.3
1.5
1.65
V
I
DD
Operating
Current
V
DD
= 1.5V, No load
--
60
100
mkA
I
STB
Standby
Current
V
DD
= 1.5V
--
0.3
1.0
mkA
F
OSC
Oscillating
Frequency
V
DD
= 1.5V, R
OSC
= 820kOhm 25.6 32 38.4 kHz
RC
Temperature Measurement
Accuracy at Range 35C~39C
-- -
0.1
--
0.1
C
LCD Electrode Pattern
SA1 SA2 SA3 SB1 SB2 SB3 SC1 SC2 SC3 SD1 SD2 SD3 SE1
COM1
F1 A1 B1 F2 A2 B2 F3 A3 B3 F4 A4 B4 A5
COM2
E1 G1 C1 E2 G2 C2 E3 G3 C3 E4 G4 C4 B5
COM3
H1 D1 -- -- D2 H2 -- D3 -- I4 D4 H4 C5
Note: 1/3 duty, 1/2 bias (LCD uses 3V)
Functional Description
Power sw: push switch to turn the power on or off.
When power on: push the switch, then it will generate a "beep" sound for 0.125 sec.
a. First displays all the segments on for 2 sec.
b. After a., as described above, then shows the last-time measured temperature for 2.8 sec.
c. After b., shows the self-test temperature (37.000.01C ) for 1 sec. The C mark
will flash at a speed of
1Hz.
d. After c., displays the highest measured temperature, then the C mark will flash at a speed of 1Hz.
e. If the temperature is < 32.00C, the display shows Lo C.
f. If the temperature is . 43.00C, the display shows Hi C.
g. The display always shows the higher temperature during the temperature measurement.
h. If the measured temperature does not change for more than 8 sec, the measurement is over and
the C mark flash stops.
i. When measurement is over, if the temperature > 37.50C the buzzer alarms
"beep-beep-beep---beep-beep-beep---" for 4 sec, as follows:
BI ------ BI ------ BI ------ ------
(0.175S) (0.175S) (0.175S) (0.175S) (0.175S) (0.175S) (0.375S)
if the temperature . 37.50C, the buzzer alarms "beep-beep-beep-beep-" for 4 sec, as follows:
BI ----
(0.5S) (0.5S)
j. It will automatically turn the power off when measurement is over for 8 min 40 sec.
k. When measurement is over, but if the temperature rises within 8 min 40 sec, the C mark will flash
again ( repeat from step 2-d), and starts to count 8 min 40 sec again.
IZ8005
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l. When beep sound is on for 4 sec, the temperature is not measured.
When "Power OFF" type standby current is 0.3 mkA.
The frequency of the buzzer is 4kHz or 8kHz by pin option.
Fever alarm is pin option.
Measurement to 0.01 degree at C.
Sensor use 503ET.
Reference resistor is the value (sensor in 37.00C)
The low battery and "M" flag cannot display when the temperature shows Hi or Lo.
When battery voltage is low, the battery mark "N" flashes at a speed of 1Hz and the
measurement may not be accurate. The low voltage detect: 1.35V 0.05V.
During the process of mass production, in order to adjust the reference resistance (RF), let test 2
be floating, the measured temperature will be the actual temperature of the measured environment. It can be
up or down, not always the higher one.
Flow Chart
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