LM397MF National Semiconductor, LM397MF Datasheet - Page 5

• Manufacturer Part Number: LM397MF
• Manufacturer: National Semiconductor

Specifications of LM397MF

• Number Of Elements: 1
• Output Type: Open Collector
• Technology: Bipolar
• Input Offset Voltage: 7@30VmV
• Input Bias Current (typ): 250nA
• Single Supply Voltage (typ): 9/12/15/18/24/28V
• Dual Supply Voltage (typ): ±3/±5/±9/±12V
• Supply Current (max): 0.7@5VmA
• Voltage Gain In Db: 101.6dB
• Power Supply Requirement: Single/Dual
• Single Supply Voltage (min): 5V
• Single Supply Voltage (max): 30V
• Dual Supply Voltage (min): ±2.5V
• Dual Supply Voltage (max): ±15V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 5
• Package Type: SOT-23
• Dc: N/A
• Lead Free Status / RoHS Status: Not Compliant

Application Notes
(Continued)
Input Stage
The LM397 has a bipolar input stage. The input common
mode voltage range is from 0 to (V
– 1.5V).
S
Output Stage
The LM397 has an open collector grounded-emitter NPN
output transistor for the output stage. This requires an exter-
nal pull-up resistor connected between the positive supply
voltage and the output. The external pull-up resistor should
be high enough resistance so to avoid excessive power
dissipation. In addition, the pull-up resistor should be low
enough resistance to enable the comparator to switch with
the load circuitry connected. Because it is an open collector
output stage, several comparator outputs can be connected
together to create an OR’ing function output. With an open
collector, the output can be used as a simple SPST switch to
ground.The amount of current which the output can sink is
approximately 10mA. When the maximum current limit is
reached, the output transistor will saturate and the output will
rise rapidly (Figure 4).
20022107
FIGURE 4. Output Saturation Voltage vs. Output Sink
Current
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