NSC LM615AIN Lm615 quad comparator and adjustable reference Datasheet

LM615 Quad Comparator and Adjustable Reference
General Description
Features
The comparators have an input range which extends to the
negative supply, and have open-collector outputs. Improved
over the LM139 series, the input stages of the comparators
have lateral PNP input transistors which enable low input
currents for large differential input voltages and swings
above V a .
The voltage reference is a three-terminal shunt-type bandgap, and is referred to the Vb terminal. Two resistors program the reference from 1.24V to 6.3V, with accuracy of
g 0.6% available. The reference features operation over a
shunt current range of 17 mA to 20 mA, low dynamic impedance, broad capacitive load range, and cathode terminal
voltage ranging from a diode-drop below V b to above V a .
As a member of National’s Super-Block TM family, the
LM615 is a space-saving monolithic alternative to a multichip solution, offering a high level of integration without sacrificing performance.
COMPARATORS
Y Low operating current
Y Wide supply voltage range
Y Open-collector outputs
Y Input common-mode range
Y Wide differential input voltage
REFERENCE
Y Adjustable output voltage
Y Tight initial tolerance available
Y Wide operating current range
Y Tolerant of load capacitance
600 mA
4V to 36V
Vb to (V a b 1.8V)
g 36V
1.24V to 6.3V
g 0.6% (25§ C)
17 mA to 20 mA
Applications
Y
Y
Y
Y
Y
Adjustable threshold detector
Time-delay generator
Voltage window comparator
Power supply monitor
RGB level detector
Connection Diagram
N Package
M Package
TL/H/11057 – 24
TL/H/11057 – 1
Top View
Top View
Ordering Information
For information about surface-mount packaging of this device, please contact the
Analog Product Marketing group at National Semiconductor Corp. headquarters.
Reference
Tolerances
Temperature Range
Military
b 55§ C s TJ s a 125§ C
b 40§ C s TJ s a 85§ C
LM615AMN
LM615AIN
g 0.6% at 25§ C,
80 ppm/§ C max
Industrial
LM615MN
NSC
Package Number
16-Pin
Molded DIP
N16A
16-Pin
Ceramic DIP
J16A
LM615IN
16-Pin
Molded DIP
N16A
LM615IM
16-Pin Narrow
Surface Mount
M16A
LM615AMJ/883
(Note 13)
g 2.0% at 25§ C,
150 ppm/§ C max
Package
Super-BlockTM is a trademark of National Semiconductor Corporation.
C1995 National Semiconductor Corporation
TL/H/11057
RRD-B30M115/Printed in U. S. A.
LM615 Quad Comparator and Adjustable Reference
December 1994
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Maximum Junction Temperature
Voltage on Any Pin Except VRO
(referred to Vbpin)
(Note 2)
(Note 3)
Soldering Information
N Package Soldering (10 seconds)
260§ C
ESD Tolerance (Note 6)
g 1 kV
36V (Max)
b 0.3V (Min)
Current through Any Input Pin
and VRO Pin
Differential Input Voltage
Output Short-Circuit Duration
Storage Temperature Range
150§ C
Thermal Resistance, Junction-to-Ambient (Note 5)
N Package
95§ C/W
Operating Temperature Range
g 20 mA
LM615AI, LM615I
LM615A, LM615M
g 36V
(Note 4)
b 40§ C s TJ s a 85§ C
b 55§ C s TJ s a 125§ C
b 65§ C s TJ s a 150§ C
Electrical Characteristics
These specifications apply for Vb e GND e 0V, V a e 5V, VCM e VOUT e V a /2, IR e 100 mA, FEEDBACK pin shorted to
GND, unless otherwise specified. Limits in standard typeface are for TJ e 25§ C; limits in boldface type apply over the
Operating Temperature Range.
Symbol
Parameter
Conditions
Typical
(Note 7)
LM615AM
LM615AI
Limits
(Note 8)
LM615M
LM615I
Limits
(Note 8)
Units
COMPARATORS
IS
Total Supply Current
a
V Current, RLOAD e % ,
a
3V s V s 36V
250
350
550
600
600
650
mA max
mA max
VOS
Offset Voltage over
V a Range
4V s V a s 36V, RL e 15 kX
1.0
2.0
3.0
6.0
5.0
7.0
mV max
mV max
VOS
Offset Voltage over
VCM Range
0V s VCM s (V a b1.8V)
V a e 30V, RL e 15 kX
1.0
1.5
3.0
6.0
5.0
7.0
mV max
mV max
DVOS
DT
Average Offset
Voltage Drift
IB
Input Bias Current
b5
b8
25
30
35
40
nA max
nA max
IOS
Input Offset Current
0.2
0.3
4
5
4
5
nA max
nA max
AV
Voltage Gain
RL e 10 kX to 36V,
2V s VOUT s 27V
500
50
50
100
V/mV
min
V/mV
tR
Large Signal
Response Time
V a IN e 1.4V, VbIN e TTL
Swing, RL e 5.1 kX
1.5
2.0
ms
ms
ISINK
Output Sink Current
V a IN e 0V, VbIN e 1V,
15
VOUT e 1.5V
VOUT e 0.4V
IL
Output Leakage
Current
V a IN e 1V, VbIN e 0V,
VOUT e 36V
2
mV/§ C
20
13
10
8
10
8
mA min
mA min
2.8
2.4
1.0
0.5
0.8
0.5
mA min
mA min
0.1
0.2
10
10
mA max
mA
Electrical Characteristics
These specifications apply for Vb e GND e 0V, V a e 5V, VCM e VOUT e V a /2, IR e 100 mA, FEEDBACK pin shorted to
GND, unless otherwise specified. Limits in standard typeface are for TJ e 25§ C; limits in boldface type apply over the
Operating Temperature Range. (Continued)
Symbol
Parameter
LM615AM
LM615AI
Limits
(Note 8)
LM615M
LM615I
Limits
(Note 8)
1.244
1.2365
1.2515
( g 0.6%)
1.2191
1.2689
( g 2%)
18
80
150
Typical
(Note 7)
Conditions
Units
VOLTAGE REFERENCE (Note 9)
VR
Reference
Voltage
DVR
DT
Average Drift
with Temperature
DVR
kH
Average Drift
with Time
DVR
DTJ
Hysteresis
(Note 11)
DVR
DIR
VR Change
with Current
VR[100 mA] b VR[17 mA]
0.05
0.1
1
1.1
1
1.1
mV max
mV max
VR[10 mA] b VR[100 mA]
(Note 12)
1.5
2.0
5
5.5
5
5.5
mV max
mV max
(Note 10)
TJ e 40§ C
TJ e 150§ C
V min
V max
ppm/§ C
max
400
1000
ppm/kH
ppm/kH
3.2
mV/§ C
R
Resistance
DVR[10 mA to 0.1 mA] /9.9 mA
DVR[100 mA to 17 mA] /83 mA
0.2
0.6
0.56
13
0.56
13
X max
X max
DVR
DVRO
VR Change
with VRO
VR[VRO
2.5
2.8
5
10
5
10
mV max
mV max
DVR
DV a
VR Change
with V a Change
VR[V a
e 5V] b
VR[V a
e 36V]
0.1
0.1
1.2
1.3
1.2
1.3
mV max
mV max
VR[V a
e 5V] b
VR[V a
e 3V]
0.01
0.01
1
1.5
1
1.5
mV max
mV max
35
40
50
55
nA max
nA max
e VR] b
VR[VRO
e 6.3V]
IFB
FEEDBACK
Bias Current
Vb s VFB s 5.06V
22
29
en
Voltage Noise
BW e 10 Hz to 10 kHz
30
mVRMS
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 V a is 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 an Output to Vb will not cause power dissipation, so it may be continuous. However, shorting an 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 the total power from all shorted outputs causes the junction temperature to exceed 150§ C, degraded reliability or destruction of the device may occur. To
determine junction temperature, see Note 5.
Note 5: Junction temperature may be calculated using TJ e TA a PD iJA. The given thermal resistance is worst-case for packages in sockets in still air. For
packages soldered to copper-clad board with dissipation from one comparator or reference output transistor, nominal iJA is 80 § C/W for the N package.
Note 6: Human body model, 100 pF discharge through a 1.5 kX resistor.
Note 7: Typical values in standard typeface are for TJ e 25§ C; values in boldface type apply for the full operating temperature range. These values represent the
most likely parametric norm.
Note 8: All limits are guaranteed for TJ e a 25§ C (standard type face) or over the full operating temperature range (bold type face).
Note 9: VRO is the reference output voltage, which may be set for 1.2V to 6.3V (see Application Information). VR is the VRO-to-FEEDBACK voltage (nominally
1.244V).
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
106 # DVR/VR[25§ C] # DTJ, where DVR is the lowest value subtracted from the highest, VR[25§ C] is the value at 25§ C, and DTJ is the temperature range. This
parameter is guaranteed by design and sample testing.
Note 11: Hysteresis is the change in VRO caused by a change in TJ, after the reference has been ‘‘dehysterized.’’ To dehysterize the reference; that is minimize the
hysteresis to the typical value, its junction temperature should be cycled in the following pattern, spiraling in toward 25§ C: 25§ C, 85§ C, b 40§ C, 70§ C, 0§ C, 25§ C.
Note 12: Low contact resistance is required for accurate measurement.
Note 13: A military RETS electrical test specification is available on request. The LM615AMJ/883 may also be procured as a Standard Military Drawing.
3
Simplified Schematic Diagrams
Comparator
TL/H/11057 – 2
Reference
Bias
TL/H/11057 – 3
4
Typical Performance Characteristics (Reference)
TJ e 25§ C, FEEDBACK pin shorted to V b e 0V, unless otherwise noted.
Reference Voltage
vs Temperature
Reference Voltage
Drift vs Time
Accelerated Reference
Voltage Drift vs Time
Reference Voltage
vs Current
and Temperature
Reference Voltage
vs Reference Current
Reference Voltage
vs Reference Current
Reference AC
Stability Range
FEEDBACK Current
vs FEEDBACK-to-Vb
Voltage
FEEDBACK Current
vs FEEDBACK-to-Vb
Voltage
Reference Noise
Voltage vs Frequency
Reference Small-Signal
Resistance vs Frequency
Reference Voltage
vs Current
and Temperature
TL/H/11057 – 4
5
Typical Performance Characteristics (Reference) (Continued)
TJ e 25§ C, FEEDBACK pin shorted to V b e 0V, unless otherwise noted.
Reference
Power-Up Time
Reference Voltage
with FEEDBACK
Voltage Step
Reference Step Response
for 100 m E 10 mA
Current Step
Reference Voltage
with 100 E 12 mA
Current Step
Reference Voltage
Change with Supply
Voltage Step
TL/H/11057 – 5
Typical Performance Characteristics (Comparators)
TJ e 25§ C, V a e 5V, Vb e 0V, unless otherwise noted
Supply Current
vs Supply Voltage
Input-Bias
Current vs Common-Mode
Voltage
Input Current vs
Differential Input Voltage
TL/H/11057 – 6
6
Typical Performance Characteristics (Comparators) (Continued)
Output Saturation
Voltage vs Sink Current
Small-Signal Response
TimesÐInverting Input,
Negative Transition
Small-Signal Response
TimesÐInverting Input,
Positive Transition
Small-Signal Response
Times Non-Inverting Input,
Positive Transition
Small-Signal Response
TimesÐNon-Inverting Input,
Negative Transition
Large-Signal Response
TimesÐInverting Input,
Positive Transition
Large-Signal Response
Times-Inverting Input,
Negative Transition
Large-Signal Response
TimesÐNon-Inverting Input,
Positive Transition
Large-Signal Response
TimesÐNon-Inverting Input,
Negative Transition
TL/H/11057 – 8
7
Application Information
Capacitors in parallel with the reference are allowed. See
the Reference AC Stability Range typical curve for capacitance valuesÐfrom 20 mA to 3 mA any capacitor value is
stable. With the reference’s wide stability range with resistive and capacitive loads, a wide range of RC filter values
will perform noise filtering.
Adjustable Reference
The FEEDBACK pin allows the reference output voltage,
Vro, to vary from 1.24V to 6.3V. The reference attempts to
hold Vr at 1.24V. If Vr is above 1.24V, the reference will
conduct current from Cathode to Anode; FEEDBACK current always remains low. If FEEDBACK is connected to Anode, then Vro e Vr e 1.24V. For higher voltages FEEDBACK is held at a constant voltage above AnodeÐsay
3.76V for Vro e 5V. Connecting a resistor across the constant Vr generates a current I e R1/Vr flowing from Cathode into FEEDBACK node. A Thevenin equivalent 3.76V is
generated from FEEDBACK to Anode with R2 e 3.76/I.
Keep I greater than one thousand times larger than FEEDBACK bias current for k0.1% errorÐI t 32 mA for the military grade over the military temperature range (I t 5.5 mA
for a 1% untrimmed error for an industrial temperature
range part).
VOLTAGE REFERENCE
Reference Biasing
The voltage reference is of a shunt regulator topology that
models as a simple zener diode. With current Ir flowing in
the ‘‘forward’’ direction there is the familiar diode transfer
function. Ir flowing in the reverse direction forces the reference voltage to be developed from cathode to anode. The
cathode may swing from a diode drop below Vb to the reference voltage or to the avalanche voltage of the parallel
protection diode, nominally 7V. A 6.3V reference with V a e
3V is allowed.
TL/H/11057–9
FIGURE 1. Voltage Associated with Reference
(Current Source Ir is External)
The reference equivalent circuit reveals how Vr is held at
the constant 1.2V by feedback, and how the FEEDBACK pin
passes little current.
To generate the required reverse current, typically a resistor
is connected from a supply voltage higher than the reference voltage. Varying that voltage, and so varying Ir, has
small effect with the equivalent series resistance of less
than an ohm at the higher currents. Alternatively, an active
current source, such as the LM134 series, may generate Ir.
TL/H/11057 – 12
FIGURE 4. Thevenin Equivalent of
Reference with 5V Output
TL/H/11057–10
FIGURE 2. Reference Equivalent Circuit
TL/H/11057 – 13
R1 e Vr/I e 1.24/32m e 39k
R2 e R1 [(Vro/Vr) b 1] e 39k [(5/1.24) b 1] e 118k
FIGURE 5. Resistors R1 and R2 Program
Reference Output Voltage to be 5V
TL/H/11057–11
FIGURE 3. 1.2V Reference
8
Application Information (Continued)
Understanding that Vr is fixed and that voltage sources, resistors, and capacitors may be tied to the FEEDBACK pin, a
range of Vr temperature coefficients may be synthesized.
Connecting a resistor across VRO-to-FEEDBACK creates a
0 TC current source, but a range of TCs may be synthesized.
TL/H/11057 – 14
TL/H/11057 – 17
FIGURE 6. Output Voltage has Negative Temperature
Coefficient (TC) if R2 has Negative TC
I e Vr/R1 e 1.24/R1
FIGURE 9. Current Source is Programmed by R1
TL/H/11057 – 15
FIGURE 7. Output Voltage has Positive TC
if R1 has Negative TC
TL/H/11057 – 18
FIGURE 10. Proportional-to-Absolute-Temperature
Current Source
TL/H/11057 – 19
FIGURE 11. Negative-TC Current Source
Reference Hysteresis
The reference voltage depends, slightly, on the thermal history of the die. Competitive micro-power products varyÐalways check the data sheet for any given device. Do not
assume that no specification means no hysteresis.
TL/H/11057 – 16
FIGURE 8. Diode in Series with R1 Causes Voltage
Across R1 and R2 to be Proportional to Absolute
Temperature (PTAT)
9
Application Information (Continued)
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.
COMPARATORS
Any of the comparators or the reference may be biased in
any way with no effect on the other sections of the LM615,
except when a substrate diode conducts (see Electrical
Characteristics 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 comparators will still operate correctly. Unused comparators should
have inverting input and output tied to Vb, and non-inverting
input tied to V a .
Input Stage
The input stage uses lateral PNP input transistors which,
unlike those of many op amps, have breakdown voltage
BVEBO equal to the absolute maximum supply voltage. Also,
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.
The guaranteed common-mode input voltage range for an
LM615 is Vb s VCM s (V a b 1.8V), over temperature.
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
other input is less than (V b a 32V), even if this is greater
than V a , 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 (V a b 1.8V), the
output state is also not guaranteed to be correct.
Hysteresis
Any comparator may oscillate or produce a noisy output if
the applied differential input voltage is near the comparator’s offset voltage. This usually happens when the input
signal is moving very slowly across the comparator’s switching threshold. This problem can be prevented by the addition of hysteresis, or positive feedback, as shown in Figure
12 .
Output Stage
The comparators have open-collector output stages which
require a pull-up resistor from each output pin to a positive
supply voltage of 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.
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 impacts the minimum value of the pull-up resistor.
TL/H/11057–20
FIGURE 12. RS and RF Add Hysteresis to Comparator
The amount of hysteresis added in Figure 12 is
VH e V a x
RS
(RF a RS)
R
& Va x S
for RF n RS
RF
A good rule of thumb is to add hysteresis of at least the
maximum specified offset voltage. More than about 50 mV
of hysteresis can substantially reduce the accuracy of the
comparator, since the offset voltage is effectively being increased by the hysteresis when the comparator output is
high.
10
Typical Applications
Power Supply Monitor
VOUT1 and VOUT2 are optional digital
outputs, and are LOW when the
corresponding LED is ON.
All resistors 1%
tolerance or better.
Tracking Comparator
TL/H/11057 – 21
4-Threshold Level Detector
TL/H/11057 – 22
R1–C1 removes the low-frequency signal component,
so that through R2–C2 the higherfrequency component is detected.
TL/H/11057 – 23
11
12
Physical Dimensions inches (millimeters)
Ceramic Dual-In-Line Package (J)
Order Number LM615AMJ/883
NS Package Number J16A
16-Pin Narrow Surface Mount Package (M)
Order Number LM615IM
NS Package Number M16A
13
LM615 Quad Comparator and Adjustable Reference
Physical Dimensions inches (millimeters) (Continued)
16-Pin Molded Dual-In-Line Package (N)
Order Number LM615IN or LM615MN
NS Package Number N16A
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