TL/H/7783
LM143/LM343 High Voltage Operational Amplifier
February 1995
LM143/LM343 High Voltage
Operational Amplifier
General Description
The LM143 is a general purpose high voltage operational
amplifier featuring operation to g40V, complete input over-
voltage protection up to g40V and input currents compara-
ble to those of other super-bop amps. Increased slew rate,
together with higher common-mode and supply rejection,
insure improved performance at high supply voltages. Oper-
ating characteristics, in particular supply current, slew rate
and gain, are virtually independent of supply voltage and
temperature. Furthermore, gain is unaffected by output
loading at high supply voltages due to thermal symmetry on
the die. The LM143 is pin compatible with general purpose
op amps and has offset null capability.
Application areas include those of general purpose op
amps, but can be extended to higher voltages and higher
output power when externally boosted. For example, when
used in audio power applications, the LM143 provides a
power bandwidth that covers the entire audio spectrum. In
addition, the LM143 can be reliably operated in environ-
ments with large overvoltage spikes on the power supplies,
where other internally-compensated op amps would suffer
catastrophic failure.
The LM343 is similar to the LM143 for applications in less
severe supply voltage and temperature environments.
Features
YWide supply voltage range g4.0V to g40V
YLarge output voltage swing g37V
YWide input common-mode range g38V
YInput overvoltage protection Full g40V
YSupply current is virtually independent of supply voltage
and temperature
Unique Characteristics
YLow input bias current 8.0 nA
YLow input offset current 1.0 nA
YHigh slew rateÐessentially independent of temperature
and supply voltage 2.5V/ms
YHigh voltage gainÐvirtually independent of resistive
loading, temperature, and supply voltage 100k min
YInternally compensated for unity gain
YOutput short circuit protection
YPin compatible with general purpose op amps
Connection Diagram
Metal Can Package
Top View
TL/H/77831
Order Number LM143H, LM143H/883*or LM343H
See NS Package Number H08C
*Available per SMDÝ7800303
C1995 National Semiconductor Corporation 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.
(Note 4)
LM143 LM343
Supply Voltage g40V g34V
Power Dissipation (Note 1) 680 mW 680 mW
Differential Input Voltage (Note 2) 80V 68V
Input Voltage (Note 2) g40V g34V
Operating Temperature Range b55§Ctoa
125§C0
§
Ctoa
70§C
Storage Temperature Range b65§Ctoa
150§Cb65§Ctoa
150§C
Output Short Circuit Duration 5 seconds 5 seconds
Lead Temperature (Soldering, 10 sec.) 300§C 300§C
ESD rating to be determined.
Electrical Characteristics (Note 3)
Parameter Conditions LM143 LM343 Units
Min Typ Max Min Typ Max
Input Offset Voltage TAe25§C 2.0 5.0 2.0 8.0 mV
Input Offset Current TAe25§C 1.0 3.0 1.0 10 nA
Input Bias Current TAe25§C 8.0 20 8.0 40 nA
Supply Voltage TAe25§C10 100 10 200 mV/V
Rejection Ratio
Output Voltage Swing TAe25§C, RLt5kX22 25 20 25 V
Large Signal Voltage TAe25§C, VOUT eg10V, 100k 180k 70k 180k V/V
Gain RLt100 kX
Common-Mode TAe25§C80 90 70 90 dB
Rejection Ratio
Input Voltage Range TAe25§Cg24 g26 g22 g26 V
Supply Current (Note 5) TAe25§C 2.0 4.0 2.0 5.0 mA
Short Circuit Current TAe25§C2020mA
Slew Rate TAe25§C, AVe1 2.5 2.5 V/ms
Power Bandwidth TAe25§C, VOUT e40 Vp-p,20k 20k Hz
RLe5kX, THD s1%
Unity Gain Frequency TAe25§C 1.0M 1.0M Hz
Input Offset Voltage TAeMax 6.0 10 mV
TAeMin 6.0 10
Input Offset Current TAeMax 0.8 4.5 0.8 14 nA
TAeMin 1.8 7.0 1.8 14
Input Bias Current TAeMax 5.0 35 5.0 55 nA
TAeMin 16 35 16 55
Large Signal Voltage RLt100 kX,T
AeMax 50k 150k 50k 150k V/V
Gain RLt100 kX,T
AeMin 50k 220k 50k 220k
Output Voltage Swing RLt5.0 kX,T
AeMax 22 26 20 26 V
RLt5.0 kX,T
AeMin 22 25 20 25
Note 1: Absolute maximum ratings are not necessarily concurrent, and care must be taken not to exceed the maximum junction temperature of the LM143 (150§C)
or the LM343 (100§C). For operating at elevated temperatures, devices in the H08 package must be derated based on a thermal resistance of 155§C/W, junction to
ambient, or 20§C/W, junction to case.
Note 2: For supply voltage less than g40V for the LM143 and less than g34V for the LM343, the absolute maximum input voltage is equal to the supply voltage.
Note 3: These specifications apply for VSeg28V. For LM143, TAemax e125§C and TAemin eb
55§C. For LM343, TAemax e70§C and TAemin e
0§C.
Note 4: Refer to RETS143X for LM143H and LM1536H military specifications.
Note 5: The maximum supply currents are guaranteed at VSeg40V for the LM143 and VSeg34V for the LM343.
2
Schematic Diagram
TL/H/77832
3
Typical Performance Characteristics
Voltage Follower Slew Rate Supply Current Short Circuit Current
Unity Gain Bandwidth Input Noise Voltage Input Noise Current
Common-Mode Rejection Power Supply Rejection Response
Large Signal Frequency
Response
Open Loop Frequency
Response
Voltage Follower Pulse
Inverter Pulse Response
TL/H/77834
4
Typical Performance Characteristics (Continued)
Input Voltage Range Output Voltage Swing Voltage Gain
Supply Current Input Current Voltage Gain
TL/H/77833
Application Hints (See AN-127)
The LM143 is designed for trouble free operation at any
supply voltage up to and including the guaranteed maximum
of g40V. Input overvoltage protection, both common-mode
and differential, is 100% tested and guaranteed at the maxi-
mum supply voltage. Furthermore, all possible high voltage
destructive modes during supply voltage turn-on have been
eliminated by design. As with most IC op amps, however,
certain precautions should be observed to insure that the
LM143 remains virtually blow-out proof.
Although output short circuits to ground or either supply can
be sustained indefinitely at lower supply voltages, these
short circuits should be of limited duration when operating at
higher supply voltages. Units can be destroyed by any com-
bination of high ambient temperature, high supply voltages,
and high power dissipation which results in excessive die
temperature. This is also true when driving low impedance
or reactive loads or loads that can revert to low impedance;
for example, the LM143 can drive most general purpose op
amps outside of the maximum input voltage range, causing
heavy current to flow and possibly destroying both devices.
Precautions should be taken to insure that the power sup-
plies never become reversed in polarityÐeven under tran-
sient conditions. With reverse voltage, the IC will conduct
excessive current, fusing the internal aluminum intercon-
nects. Voltage reversal between the power supplies will al-
most always result in a destroyed unit.
In high voltage applications which are sensitive to very low
input currents, special precautions should be exercised. For
example, with high source resistances, care should be tak-
en to prevent the magnitude of the PC board leakage cur-
rents, although quite small, from approaching those of the
op amp input currents. These leakage currents become
larger at 125§C and are made worse by high supply volt-
ages. To prevent this, PC boards should be properly
cleaned and coated to prevent contamination and to pro-
vide protection from condensed water vapor when operat-
ing below 0§C. A guard ring is also recommended to signifi-
cantly reduce leakage currents from the op amp input pins
to the adjacent high voltage pins in the standard op amp pin
connection as shown in
Figure 1. Figures 2, 3
and
4
show
how the guard ring is connected for the three most common
op amp configurations.
Finally, caution should be exercised in high voltage applica-
tions as electrical shock hazards are present. Since the
negative supply is connected to the case, users may inad-
vertantly contact voltages equal to those across the power
supplies.
The LM143 can be used as a plug-in replacement in most
general purpose op amp applications. The circuits present-
ed in the following section emphasize those applications
which take advantage of the unique high voltage abilities of
the LM143.
5
Application Hints (See AN-127) (Continued)
TL/H/77835
Bottom View
FIGURE 1. Printed Circuit Layout for Input
Guarding with TO-5 Package
R3 aR1 cR2
R1 aR2 eRSOURCE TL/H/77837
FIGURE 3. Guarded Non-Inverting Amplifier
R1 eRSOURCE
TL/H/77836
FIGURE 2. Guarded Voltage Follower
R3 eR1 cR2
R1 aR2
TL/H/77838
FIGURE 4. Guarded Inverting Amplifier
TL/H/778314
FIGURE 5. Offset Voltage Adjustment
6
Typical Applications ³(For more detail see AN-127)
130 Vp-p Drive Across a Floating Load
TL/H/77839
g34V Common-Mode Instrumentation Amplifier
AVe#1a2R1
R2 JR5
R4 WHERE: R4 eR6
R5 eR7 TL/H/778310
*R2 may be adjustable to trim the gain.
**R7 may be adjusted to compensate for the resistance tolerance of R4R7 for best CMR.
³The 38V supplies allow for a 5% voltage tolerance. All resistors are (/2 watt, except as noted.
7
Typical Applications ³(Continued) (For more detail see AN-127)
Tracking g65V, 1 Amp Power Supply with Short Circuit Protection
²Put on common heat sink.
All resistors are (/2 watt, 5%, except as noted.
TL/H/778311
³The 38V supplies allow for a 5% voltage tolerance. All resistors are (/2 watt, except as noted.
8
Typical Applications ³(Continued) (For more detail see AN-127)
90W Audio Power Amplifier with Safe Area Protection
²Put on common heat sink
*34 turns of no. 20 wire on a */8×form
**Adjust R6 to set IQe100 mA TL/H/778312
³The 38V supplies allow for a 5% voltage tolerance. All resistors are (/2 watt, except as noted.
9
Typical Applications ³(Continued) (For more detail see AN-127)
1 Amp Power Amplifier with Short Circuit Protection
TL/H/778313
³The 38V supplies allow for a 5% voltage tolerance. All resistors are (/2 watt, except as noted.
10
11
LM143/LM343 High Voltage Operational Amplifier
Physical Dimensions inches (millimeters)
Metal Can Package (H)
Order Number LM143H, LM143H/883 or LM343H
NS Package Number H08C
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