ICL8211CTY Intersil Corporation, ICL8211CTY Datasheet - Page 8

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

Typical Performance Curves
(ICL8212 ONLY) (Continued)
FIGURE 18. OUTPUT SATURATION VOLTAGE AND CURRENT
FIGURE 19. OUTPUT CURRENT AS A FUNCTION OF OUTPUT
FIGURE 20. HYSTERESIS OUTPUT CURRENT AS A FUNCTION
40
30
20
10
0.6
0.5
0.4
0.3
0.2
0.1
0
-10
-15
-20
-25
-30
-35
-40
0
0.1
-5
-55
AS A FUNCTION OF TEMPERATURE
VOLTAGE
OF HYSTERESIS OUTPUT VOLTAGE
0
-10.00
T
V+ = +5V
A
= +25
HYSTERESIS OUTPUT VOLTAGE
-25
o
C
V
V
OUTPUT VOLTAGE
V
T
1.0
-1.00
T
+5
T
= 1.153V
TEMPERATURE (
= 1.18V
OUTPUT SAT.
CURRENT
= 1.152V
(V
O
= 4.0V)
+35
V
V
V
TH
TH
TH
-0.10
10.0
+65
VOLTAGE SAT.
CURRENT
(I
= 1.153V
=1.25V
T
V+ = +10V
= 1.158V
O
A
= 10mA)
o
V+ = +5V
V
= +25
C)
TH
+95
= 1.2V
30.0 100.0
o
C
-0.01
ICL8211, ICL8212
+125
7-168
Detailed Description
The ICL8211 and ICL8212 use standard linear bipolar
integrated circuit technology with high value thin film
resistors which define extremely low value currents.
Components Q
accurate voltage reference of 1.15V. This reference voltage
is close to the value of the bandgap voltage for silicon and is
highly stable with respect to both temperature and supply
voltage. The deviation from the bandgap voltage is
necessary due to the negative temperature coefficient of the
thin film resistors (-5000 ppm per
Components Q
current source; Q
mirror. Q
current mirror, the collector currents of Q
to be equal and it can be shown that the collector current in
Q
or approximately 1 A at +25
Where k = Boltzman’s Constant
Transistors Q
and Q
ensures a constant current supply free from variations.
The base current of Q
the constant source; there being two stable states for this
type of circuit - either ON as defined above, or OFF if no start
up current is provided. Leakage current in the transistors is
not sufficient in itself to guarantee reliable startup.
Q
IC and V
generate the bandgap voltage, it is necessary to sum a
voltage equal to the base emitter voltage of Q
proportional to the difference of the base emitter voltages of
two transistors Q
The total supply current consumed by the voltage reference
section is approximately 6 A at room temperature. A voltage
at the THRESHOLD input is compared to the reference 1.15V
by the comparator consisting of transistors Q
The outputs from the comparator are limited to two diode
drops less than V+ or approximately 1.1V. Thus the base cur-
rent into the hysteresis output transistor is limited to about
500nA and the collector current of Q
In the case of the ICL8211, Q
times the emitter area of Q
current to approximately 7mA, whereas for the ICL8212
Thus 1.5 = V
which provides:
8
4
and T = Absolute Temperature in
and Q
is matched to Q
9
q = Charge on an Electron
remain constant with supply voltage variations. This
8
9
BE
has 7 times the emitter area of Q
is
BE
IC (Q
of Q
5
, Q
(Q
1
2
8
9
through Q
8
through Q
2
6
10
or Q
and Q
R
R
or Q
, and Q
3
and Q
3
2
and Q
are identical to that of Q
1
10
9
= 12 (approximately.)
provides sufficient start up current for
) =
) +
9
3
operating at two current densities.
7
2
10
are identical and form a current
; Q
9
o
assure that the V
R2
C
R
R
20
1
and R
and R
21
10
3
2
o
thereby limiting the output
is proportioned to have 70
is matched to Q
o
K
C).
x
x
19
1
2
, R
to 100 A.
make up a constant
kT
q
kT
2
8
q
and Q
and R
9
In7
, and due to the
11
CE
9
through Q
9
9
to a voltage
3
9
of Q
are forced
or Q
. Thus the
set up an
3
8
, Q
. To
17
4
,
.