LM7131ACM5X National Semiconductor, LM7131ACM5X Datasheet - Page 21

• Manufacturer Part Number: LM7131ACM5X
• Description: IC OP AMP TINY HI SPEED SOT23-5
• Manufacturer: National Semiconductor

Specifications of LM7131ACM5X

• Amplifier Type: Voltage Feedback
• Number Of Circuits: 1
• Slew Rate: 150 V/µs
• Gain Bandwidth Product: 70MHz
• -3db Bandwidth: 90MHz
• Current - Input Bias: 20µA
• Voltage - Input Offset: 20µV
• Current - Supply: 7.5mA
• Current - Output / Channel: 65mA
• Voltage - Supply, Single/dual (±): 2.7 V ~ 12 V, ± 2.5 V ~ 6 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-5, SC-74A, SOT-25
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Output Type: -
• Other names: LM7131ACM5XTR

Using the LM7131
systems and a somewhat narrow range for +3V systems.
One way to increase this output range is to have the output
load referenced to ground — this will allow the output to
swing lower. Another is to use higher load impedances. The
output swing specifications show typical numbers for swing
with loads of 600Ω to ground. Note that these typical num-
bers are similar to those for a 150Ω load. These typical
numbers are an indication of the maximum DC performance
of the LM7131.
The sinking output of the LM7131 is somewhat lower than
the amplifier’s sourcing capability. This means that the
LM7131 will not drive as much current into a load tied to 2.5
V as it will drive into a load tied to 0V.
Good AC performance will require keeping the output further
away from the supply rails. For a +5V supply and relatively
high impedance load (analog-to-digital converter input) the
following are suggested as an initial starting range for
achieving high (
Upper output level —
Approximately 0.8V to 1V below the positive (V+) rail.
Lower output level —
Approximately 200 mV–300 mV above the negative rail.
The LM7131 very useful in virtual ground systems as an
output device for output loads which are referenced to 0V or
>
60 dB) AC accuracy
(Continued)
FIGURE 15. D/A Ouput Amplifier
21
the lower rail. It is also useful as a driver for capacitive loads,
such as sample and hold circuits, and audio analog to digital
converters. If fast amplifiers with rail-to-rail output ranges are
needed, please see the National Semiconductor LM6142
datasheet.
D/A Output Amplifier
The LM7131 can be used as an output amplifier for fast
digital-to-analog converters. When using the LM7131 with
converters with an output voltage range which may exceed
the differential input voltage limit of
to add protection diodes to the inputs. See Figure 15. For
high speed applications, it may be useful to consider low
capacitance schottky diodes. Additional feedback capaci-
tance may be needed to control ringing due to the additional
input capacitance from the D/A and protection diodes. When
used with current output D/As, the input bias currents may
produce a DC offset in the output. This offset may be can-
celed by a resistor between the positive input and ground.
Spice Macromodel
A SPICE macromodel of the LM7131 and many other Na-
tional Semiconductor op amps is available at no charge from
your National Semiconductor representative.
01231324
±
2V, it may be necessary
www.national.com