Explore LM2907-N pins, signal names, electrical functions and connection guidance for each package.
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The input comparator detects alternating positive and negative excursions relative to ground.
Apply a 1 kHz sine wave with 1 V peak amplitude and zero DC offset in the example.
The eight-pin part needs both polarities; an ordinary 0–5 V logic waveform is not a direct substitute.
An internal current charges and discharges C1 on alternate input half cycles.
Connect C1 = 1 nF to GND.
Keep C1 above 500 pF for accurate operation and internal compensation.
Mirrored current pulses feed R1 and C2. This node is also the amplifier noninverting input in the eight-pin device.
Connect 100 kΩ and 1 µF in parallel to GND.
The pump output is a current-producing node, not a rail-to-rail logic signal.
Buffered output in the voltage-follower connection.
Join to IN−7, a high-impedance voltmeter and a 10 kΩ load to GND.
Separate collector of the internal amplifier output transistor.
Join to the +12 V supply for the emitter-follower example.
COL is not internally tied to V+.
Powers the input comparator, charge pump and amplifier.
Use a regulated +12 V rail with 100 nF and local bulk bypass to GND.
Conversion gain is proportional to this supply; LM2907 has no LM2917-style internal Zener regulator.
Negative-feedback input for the output amplifier.
Connect directly to EMIT4 for unity-gain buffering.
CP2 / IN+3 and IN−7 must remain within the amplifier common-mode region.
Internally connects the negative tachometer input to device ground in the eight-pin variant.
Connect externally to circuit GND, including the signal-generator return.
The internal connection does not eliminate the external ground connection.
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