LM612AMN [NSC]
Dual-Channel Comparator and Reference; 双通道比较器和参考
| 型号： | LM612AMN |
| 厂家： | 
National Semiconductor |
| 描述： | Dual-Channel Comparator and Reference |
| 文件： | 总10页 (文件大小：246K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
February 1995
LM612
Dual-Channel Comparator and Reference
General Description
Features
COMPARATORS
The dual-channel comparator consists of two individual
comparators, having an input voltage range that extends
down to the negative supply voltage Vb. The common
open-collector output can be driven low by either half of the
LM612. This configuration makes the LM612 ideal for use
as a window comparator. The input stages of the compara-
tor have lateral PNP input transistors which maintain low
input currents for large differential input voltages and swings
Y
Low operating current
300 mA
Y
Wide supply voltage range
4V to 36V
Y
Open-collector outputs
Input common-mode range
Vb to (Va
Y
b
1.8V)
Y
g
Wide differential input voltage
36V
REFERENCE
above Va
.
Y
Fixed output voltage
1.24V
The 1.2V voltage reference, referred to the Vb terminal, is a
two-terminal shunt-type band-gap similar to the LM185-1.2
Y
g
Tight initial tolerance available
0.6% (25 C)
§
Y
Wide operating current range
17 mA to 20 mA
g
series, with voltage accuracy of 0.6% available. The refer-
Y
Tolerant of load capacitance
ence features operation over a shunt current range of 17 mA
to 20 mA, low dynamic impedance, and broad capacitive
load range.
Applications
Y
Voltage window comparator
As
a member of National’s Super-BlockTM family, the
Y
Power supply voltage monitor
LM612 is a space-saving monolithic alternative to a multi-
chip solution, offering a high level of integration without sac-
rificing performance.
Y
Dual-channel fault monitor
Connection Diagram
TL/H/11058–1
Top View
Ordering Information
For information about surface-mount packaging of this device, please contact the Analog Product Marketing group at
National Semiconductor Corporation headquarters.
Temperature Range
Military
NSC
Reference
Tolerances
Package
Package
Number
Industrial
s
s
s
40 C T
b
a
b
a
85 C
J
55 C
§
T
125 C
§
§
§
J
g
80 ppm/ C Max
0.6% at 25 C,
8-Pin
§
LM612AMN
LM612AIN
N08E
J08A
N08E
M08A
Molded DIP
§
LM612AMJ/883
(Note 13)
8-Pin
Ceramic DIP
g
150 ppm/ C Max
2.0% at 25 C,
8-Pin
§
LM612MN
LM612IN
LM612IM
Molded DIP
§
8-Pin Narrow
Surface Mount
Super-BlockTM is a trademark of National Semiconductor Corporation.
C
1995 National Semiconductor Corporation
TL/H/11058
RRD-B30M115/Printed in U. S. A.
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Thermal Resistance, Junction-to-Ambient (Note 5)
N Package
100 C/W
§
Soldering Information
N Package
Soldering (10 seconds)
Voltage on Any Pin Except V (referred to Vb pin)
R
(Note 2)
(Note 3)
36V (Max)
0.3V (Min)
260 C
§
1 kV
b
g
ESD Tolerance (Note 6)
g
Current through Any Input Pin and V Pin
R
20 mA
Operating Temperature Range
s
g
Differential Input Voltage
36V
(Note 4)
s
a
b
LM612AI, LM612I
LM612AM, LM612M
40 C
T
J
85 C
§
Output Short-Circuit Duration
§
55 C
s
s
b
a
T
J
125 C
§
§
s
s
a
b
Storage Temperature Range
65 C
§
T
J
150 C
§
Maximum Junction Temperature
150 C
§
a
Electrical Characteristics These specifications apply for Vb GND 0V, V
5V, V
CM
V
a/2,
e
25 C; limits in boldface type apply over the
e
e
e
e
e
V
OUT
e
Operating Temperature Range.
I
100 mA, unless otherwise specified. Limits in standard typeface are for T
J
§
R
LM612AM
LM612AI
Limits
LM612M
LM612I
Limits
Typical
Symbol
Parameter
Conditions
Units
(Note 7)
(Note 8)
(Note 8)
COMPARATORS
e %
I
Total Supply Current
Va Current, R
LOAD
,
150
250
250
mA Max
mA Max
S
a
s
s
3V
V
36V
170
300
300
a
s
s
e
V
OS
V
OS
Offset Voltage over
Va Range
4V
V
36V, R
15 kX
1.0
3.0
5.0
mV Max
mV Max
L
2.0
6.0
7.0
a
s
s
(V
b
Offset Voltage over
0V
V
1.8V)
1.0
3.0
5.0
mV Max
mV Max
CM
e
e
15 kX
V
Range
Va
30V, R
1.5
6.0
7.0
CM
L
DV
Average Offset Voltage
Drift
OS
15
mV/ C
§
DT
I
I
Input Bias Current
Input Offset Current
Voltage Gain
5
25
35
nA Max
nA Max
B
8
30
40
0.2
4
4
nA Max
nA Max
OS
0.3
5
5
e
s
A
t
R
10 kX to 36V,
500
50
50
V/mV Min
V/mV
V
L
s
2V
V
OUT
27V
100
e
Swing, R
e
TTL
Large Signal Response
Time
V
1.4V, V
e
1.5
ms
ms
a
b
R
IN
IN
5.1 kX
2.0
L
e
e
1V,
I
Output Sink Current
V
0V, V
20
10
10
mA Min
mA Min
a
b
b
SINK
IN
IN
IN
e
e
V
1.5V
0.4V
13
8
8
OUT
OUT
V
2.8
1.0
0.8
mA Min
mA Min
2.4
0.5
0.5
e
e
e
0V,
I
Output Leakage Current
V
V
1V, V
36V
0.1
10
10
mA Max
mA
a
L
IN
0.2
OUT
2
a
Electrical Characteristics These specifications apply for Vb GND 0V, V
5V, V
CM
V
a/2,
e
e
e
e
e
V
OUT
e
Operating Temperature Range. (Continued)
e
I
100 mA, unless otherwise specified. Limits in standard typeface are for T
J
25 C; limits in boldface type apply over the
§
R
LM612AM
LM612AI
Limits
LM612M
LM612I
Limits
Typical
(Note 7)
Symbol
Parameter
Conditions
Units
(Note 8)
(Note 8)
VOLTAGE REFERENCE (Note 9)
V
R
Reference Voltage
1.244
1.2365
1.2515
1.2191
1.2689
V Min
V Max
g
g
2%)
(
0.6%)
(
DV
Average Drift with
Temperature
(Note 10)
(Note 11)
ppm/ C
§
Max
R
18
80
150
DT
DV
e
e
Average Drift with
Time
T
T
40 C
§
150 C
400
ppm/kH
ppm/kH
R
J
1000
kH
§
J
DV
Hysteresis
R
3.2
mV/ C
§
DT
DV
J
b
V
R
Change with
V
V
0.05
1
1
mV Max
mV Max
R
[
]
[
]
R 100 mA
R 17 mA
Current
0.1
1.1
1.1
DI
R
b
V
V
1.5
5
5
mV Max
mV Max
[
R 10 mA
(Note 12)
]
[
]
R 100 mA
2.0
5.5
5.5
R
Resistance
DV
DV
/9.9 mA
]
0.2
0.6
0.56
13
0.56
13
X Max
X Max
[
R 10 mA to 0.1 mA
/83 mA
]
[
R 100 mA to 17 mA
b
DV
DVa
V
Change with
V
V
0.1
1.2
1.2
mV Max
mV Max
a e
a e
a e
R
[
R V
]
[
R V
]
36V
R
5V
Va Change
0.1
1.3
1.3
b
V
[
R V
V
[
R V
0.01
1
1
mV Max
mV Max
a e
]
]
3V
5V
0.01
1.5
1.5
e
e
n
Voltage Noise
BW
10 Hz to 10 kHz
30
mV
RMS
Note 1: Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating the
device beyond its rated operating conditions.
Note 2: Input voltage above Va is not allowed. As long as one input pin voltage remains inside the common-mode range, the comparator will deliver the correct
output.
Note 3: More accurately, it is excessive current flow, with resulting excess heating, that limits the voltages on all pins. When any pin is pulled a diode drop below
Vb, a parasitic NPN transistor turns ON. No latch-up will occur as long as the current through that pin remains below the Maximum Rating. Operation is undefined
and unpredictable when any parasitic diode or transistor is conducting.
Note 4: Shorting the Output to Vb will not cause power dissipation, so it may be continuous. However, shorting the Output to any more positive voltage (including
V
a), will cause 80 mA (typ.) to be drawn through the output transistor. This current multiplied by the applied voltage is the power dissipation in the output transistor.
If this total power causes the junction temperature to exceed 150 C, degraded reliability or destruction of the device may occur. To determine junction temperature,
§
see Note 5.
e
a
P
Note 5: Junction temperature may be calculated using T
T
i
. The given thermal resistance is worst-case for packages in sockets in still air. For
JA
J
A
D
packages soldered to copper-clad board with dissipation from one comparator or reference output transistor, nominal i is 90 C/W for the N package.
§
JA
Note 6: Human body model, 100 pF discharged through a 1.5 kX resistor.
e
Note 7: Typical values in standard typeface are for T
25 C; values in boldface type apply for the full operating temperature range. These values represent the
§
J
most likely parametric norm.
e
Note 8: All limits are guaranteed for T
25 C (standard type face) or over the full operating temperature range (bold type face).
§
J
Note 9: V is the reference output voltage, nominally 1.24V.
R
Note 10: Average reference drift is calculated from the measurement of the reference voltage at 25 C and at the temperature extremes. The drift, in ppm/ C, is
§
§
6
10
DV /V
DT , where DV is the lowest value subtracted from the highest, V
#
is the value at 25 C, and DT is the temperature range. This
§
]
R 25 C J
#
parameter is guaranteed by design and sample testing.
[
R 25 C
]
[
R
J
R
§
§
Note 11: Hysteresis is the change in V caused by a change in T , after the reference has been ‘‘dehysterized’’. To dehysterize the reference; that is minimize the
b
R
J
hysteresis to the typical value, its junction temperature should be cycled in the following pattern, spiralling in toward 25 C: 25 C, 85 C, 40 C, 70 C, 0 C, 25 C.
§
§
§
§
§
§
§
Note 12: Low contact resistance is required for accurate measurement.
Note 13: A military RETS 612AMX electrical test specification is available on request. The military screened parts can also be procured as a Standard Military
Drawing.
3
Simplified Schematic Diagrams
Comparator
TL/H/11058–2
Reference
Bias
TL/H/11058–3
4
Typical Performance Characteristics (Reference)
e
0V, unless otherwise noted
25 C, Vb
e
T
J
§
Reference Voltage
Drift vs Time
Accelerated Reference
Voltage Drift vs Time
Reference Voltage vs Temp.
e
TL/H/11058–4
5
Typical Performance Characteristics (Comparators)
25 C, Va
5V, Vb
e
e
e
0V
T
J
§
Supply Current
vs Supply Voltage
Input Bias Current vs
Common-Mode Voltage
Input Current vs
Differential Input Voltage
put,
TL/H/11058–6
6
Application Information
VOLTAGE REFERENCE
Capacitors in parallel with the reference are allowed. See
the Reference AC Stability Range typical curve for capaci-
tance valuesÐfrom 20 mA to 3 mA the reference is stable
for any value of capacitance. With the reference’s wide sta-
bility range with resistive and capacitive loads, a wide range
of RC filter values will perform noise filtering when neces-
sary.
Reference Biasing
The voltage reference is of a shunt regulator topology that
models as a simple zener diode. With current I flowing in
R
the ‘‘forward’’ direction there is the familiar diode transfer
function. I flowing in the reverse direction forces the refer-
R
ence voltage to be developed from cathode to anode.
Reference Hysteresis
The reference voltage depends, slightly, on the thermal his-
tory of the die. Competitive micro-power products varyÐal-
ways check the datasheet for any given device. Do not as-
sume that no specification means no hysteresis.
COMPARATORS
Either comparator or the reference may be biased in any
way with no effect on the other sections of the LM612, ex-
cept when a substrate diode conducts (see Electrical Char-
acteristics Note 3). For example, one or both inputs of one
comparator may be outside the input voltage range limits,
the reference may be unpowered, and the other comparator
will still operate correctly. The inverting input of an unused
comparator should be tied to Vb and the non-inverting tied
TL/H/11058–8
FIGURE 1. 1.24V Reference is Developed between
Cathode and Anode; Current Source I is External
R
The reference equivalent circuit reveals how V is held at
R
the constant 1.2V by feedback for a wide range of reverse
current.
to Va
.
Hysteresis
Any comparator may oscillate or produce a noisy output if
the applied differential input voltage is near the compara-
tor’s offset voltage. This usually happens when the input
signal is moving very slowly across the comparator’s switch-
ing threshold. This problem can be prevented by the addi-
tion of hysteresis, or positive feedback, as shown in Figure
4.
TL/H/11058–9
FIGURE 2. Reference Equivalent Circuit
To generate the required reverse current, typically a resistor
is connected from a supply voltage higher than the refer-
ence voltage to the Reference Output pin. Varying that volt-
age, and so varying I , has small effect with the equivalent
R
series resistance of less than an ohm at the higher currents.
Alternatively, an active current source, such as the LM134
TL/H/11058–11
FIGURE 4. R and R Add Hysteresis to Comparator
F
S
The amount of hysteresis added in Figure 4 is
series, may generate I
.
R
R
S
a
V
e
c
V
H
a
(R
R )
S
F
R
R
S
a
ll
R
S
&
c
V
for R
F
F
A good rule of thumb is to add hysteresis of at least the
maximum specified offset voltage. More than about 50 mV
TL/H/11058–10
FIGURE 3. 1.2V Reference
7
Application Information (Continued)
of hysteresis can substantially reduce the accuracy of the
comparator, since the offset voltage is effectively being in-
creased by the hysteresis when the comparator output is
high.
The guaranteed common-mode input voltage range for an
LM612 is Vb
(Va
s
s
b
1.8V), over temperature.
V
CM
This is the voltage range in which the comparisons must be
made. If both inputs are within this range, the output will be
at the correct state. If one input is within this range, and the
It is often a good idea to decrease the amount of hysteresis
until oscillations are observed, then use three times that
minimum hysteresis in the final circuit. Note that the amount
of hysteresis needed is greatly affected by layout. The
amount of hysteresis should be rechecked each time the
layout is changed, such as changing from a breadboard to a
P.C. board.
other input is less than (Vb 32V), even if this is greater
a
than Va, the output will be at the correct state. If, however,
either or both inputs are driven below Vb, and either input
current exceeds 10 mA, the output state is not guaranteed
to be correct. If both inputs are above (Va
b
output state is also not guaranteed to be correct.
1.8V), the
Output Stage
Input Stage
The comparators have a common open-collector output
stage which requires a pull-up resistor to a positive supply
voltage for the output to switch properly. When the internal
output transistor is off, the output (HIGH) voltage will be
pulled up to this external positive voltage.
The input stage uses lateral PNP input transistors which,
unlike those of many op amps, have breakdown voltage
BV
equal to the absolute maximum supply voltage. Also,
EBO
they have no diode clamps to the positive supply nor across
the inputs. These features make the inputs look like high
impedances to input sources producing large differential
and common-mode voltages.
To ensure that the LOW output voltage is under the TTL-low
threshold, the output transistor’s load current must be less
than 0.8 mA (over temperature) when it turns on. This im-
pacts the minimum value of the pull-up resistor.
Typical Applications
TL/H/11058–12
Power Supply Monitor with Indicator
8
Physical Dimensions inches (millimeters)
8-Pin Ceramic Dual-In-Line Package (J)
Order Number LM612AMJ/883
NS Package Number J08A
8-Pin Surface Mount Package (M)
Order Number LM612IM
NS Package Number M08A
9
Physical Dimensions inches (millimeters) (Continued)
8-Pin Molded Dual-In-Line Package (N)
Order Number LM612AMJ/883, LM612AMN, LM612AIN, LM612MN or LM612IN
NS Package Number N08E
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DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL
SEMICONDUCTOR CORPORATION. As used herein:
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systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and whose
failure to perform, when properly used in accordance
with instructions for use provided in the labeling, can
be reasonably expected to result in a significant injury
to the user.
2. A critical component is any component of a life
support device or system whose failure to perform can
be reasonably expected to cause the failure of the life
support device or system, or to affect its safety or
effectiveness.
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