ICL8211CTY Intersil Corporation, ICL8211CTY Datasheet - Page 12

• Manufacturer Part Number: ICL8211CTY
• Description: Programmable Voltage Detectors
• Manufacturer: Intersil Corporation

has occurred, even in the case where a supply voltage may
have dropped to zero. Upon power up to the normal
operating voltage this record must have been retained and
easily interrogated. This could be important in the case of a
transient power failure due to a faulty component or
intermittent power supply, open circuit, etc., where direct
observation of the failure is difficult.
A simple circuit to record an out of range voltage excursion
may be constructed using an ICL8211, an ICL8212 plus a
few resistors. This circuit will operate to 30V without exceed-
ing the maximum ratings of the ICs. The two voltage limits
defining the in range supply voltage may be set to any value
between 2.0V and 30V.
The ICL8212 is used to detect a voltage, V
upper voltage limit to the operating voltage range. The
ICL8211 detects the lower voltage limit of the operating
voltage range, V
that the output can be stable in either state over the
operating voltage range V
trip point of the ICL8211 much higher in voltage than V
The output of the ICL8212 is used to force the output of the
OFF
ON
R
R
4
5
ICL8212 DISCONNECTED
FIGURE 31. OUTPUT STATES OF THE ICL8211 AND ICL8212 AS A FUNCTION OF THE SUPPLY VOLTAGE
OUTPUT ICL8211
SUPPLY VOLTAGE
V
1
1
. Hysteresis is used with the ICL8211 so
V
1
2
3
4
NOM
FIGURE 30. NON-VOLATILE POWER SUPPLY MALFUNCTION RECORDER
1
to V
ICL8212
V
2
2
by making V
V
3
8
7
6
5
OFF
ON
2
, which is the
3
- the upper
ICL8211, ICL8212
R
3
OUTPUT ICL8212
SUPPLY VOLTAGE
2
.
RESET
7-172
R
2
V
R
NOM
S
ICL8211 into the ON state above V
of the supply voltage that will result in the output of the
ICL8211 changing from the ON state to the OFF state. This
may be achieved only by shorting out R3 for values of supply
voltage between V
Constant Current Sources (Figure 32)
The ICL8212 may be used as a constant current source of
value of approximately 25 A by connecting the THRESH-
OLD terminal to GROUND. Similarly the ICL8211 will pro-
vide a 130 A constant current source. The equivalent
parallel resistance is in the tens of megohms over the supply
voltage range of 2V to 30V. These constant current sources
may be used to provide basing for various circuitry including
differential amplifiers and comparators. See Typical Operat-
ing Characteristics for complete information.
Programmable Zener Voltage Reference (Figure 33)
The ICL8212 may be used to simulate a zener diode by
connecting the OUTPUT terminal to the V
a resistor network connected to the THRESHOLD terminal
1
1
V
2
1
2
3
4
ICL8211
1
OFF
and V
ON
2
.
8
7
6
5
AS PER FIGURE 7
OUTPUT ICL8211
SUPPLY VOLTAGE
V
1
2
. Thus there is no value
Z
R
6
output and using
OUTPUT
V
2
V+