TC1024 TELCOM [TelCom Semiconductor, Inc], TC1024 Datasheet - Page 3

• Manufacturer Part Number: TC1024
• Description: PRECISION TEMPERATURE-TO-VOLTAGE CONVERTERS WITH SHUTDOWN MODE
• Manufacturer: TELCOM [TelCom Semiconductor, Inc]

TC1023/1024-05
PRECISION TEMPERATURE-TO-VOLTAGE
CONVERTERS WITH SHUTDOWN MODE
DETAILED DESCRIPTION
TC1023 and TC1024 appears in Figure 5. The TC1023 can
be used with single power supply to measure temperatures
from 0 C to 100 C. A pull-down resistor (R1 in Figure 1)
must be added from the output pin to the negative power
supply for measuring temperatures less than 0 C. The
value of the resistor must be chosen to limit the maximum
current pulled from the output to the negative supply to
– 50 A (i.e., R1 = V
Output Stage
sourcing 1mA. These devices have a limited ability to drive
heavy capacitive loads. Loads of 50pF (to ground) can be
driven directly. For heavier loads, a 2k (or greater) resis-
tor should be placed in series with the output for decoupling.
If the TC1023/1024 is used in a noisy electrical environ-
ment, a 0.1 F bypass capacitor from V
mended.
Shutdown/Calibrate Mode
is taken to V
(typ) and the output to drop immediately to 0V through
approximately 100k . For applications where the TC1023/
1024 is connected to an external A/D converter, a refer-
ence voltage can be directly connected to V
shutdown for A/D calibration, as shown in Figure 3. A
CMOS gate provides bias voltage to the bandgap refer-
ence V
taking CE to V
limit current through the voltage reference to the desired
current (I
is the CMOS gate output high voltage at output current
equal to I
A plot of output voltage versus temperature for both the
Both devices have Class A output stages capable of
The TC1023/1024 enters shutdown when the CE input
R
, and at the same time disables the TC102x by
REF
REF
6/12/97
V
IH
). That is, R1 = (V
; and V
CC
. This causes quiescent current to fall to 1 A
CE
IH
= 2.2V to 12.0V MIN.
Figure 1. TC1023 Connections
. Limiting resistor R1 should be chosen to
TC1023
GND
V
SS
REF
CC
/50 A).
is the reference voltage of V
V
OUT
OH
– V
V
SS
R1 = V
REF
CC
)/I
to GND is recom-
SS
REF
/50 A
OUT
(where V
V
while in
OUT
R
).
OH
3
Multi-Zone Temperature Sensing
ing as shown in the example of Figure 4. In this example,
the processor addresses either of two sensors with a single
I/O port pin. The TC102x V
and routed to the processor's A/D converter, eliminating
the need for separate A/D input channels for each sensor.
The CE input facilitates multi-zone temperature sens-
Zone 1
CE
TC102x
GND
V
CE
V
CC
CC
TC102x
V
GND
V
OUT
V
Figure 4. TC1023/1024 Addressing
CC
CC
Figure 2. TC1024 Connections
TC1024 (– 20 C to +125 C)
V
CC
Figure 3. A/D Calibration
CE
V
PRELIMINARY INFORMATION
= 3.0V to 12.0V
OUT
TC1024
GND
V
CC
Zone 2
CE
OUT
2.5V
REF
V
TC102x
GND
OUT
V
CC
R1
pins are connected together
Zone 1/Zone 2
V
OUT
CONVERTER
A/D
I/O Pin
MICROCONTROLLER
CONVERTER
TC1023
TC1024
A/D
V
CMOS
GATE
OUT
CAL