Enhanced Plastic Frequency to Voltage Converter
Description
OBSOLETE
LM2907EP, LM2917EP
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SNOSAB0A – JUNE 2004 – REVISED SEPTEMBER 2011
LM2907EP /LM2917EP Enhanced Plastic Frequency to Voltage Converter
Check for Samples: LM2907EP, LM2917EP
FEATURES
1
•2 Ground referenced tachometer input interfaces directly with variable reluctance magnetic pickups
• Op amp/comparator has floating transistor output
• 50 mA sink or source to operate relays, solenoids, meters, or LEDs
• Frequency doubling for low ripple • Tachometer has built-in hysteresis with either
differential input or ground referenced input • Built-in zener on LM2917EP • ±0.
3% linearity typical • Ground referenced tachometer is fully
protected from damage due to swings above VCC and below ground
APPLICATIONS
• Selected Military Applications • Selected Avionics Applications
DESCRIPTION
The LM2907EP, LP2917EP series are monolithic frequency to voltage converters with a high gain op amp/comparator designed to operate a relay, lamp, or other load when the input frequency reaches or exceeds a selected rate.
The tachometer uses a charge pump technique and offers frequency doubling for low ripple, full input protection in two versions (LM2907-8EP, LM2917-8EP) and its output swings to ground for a zero frequency input.
The op amp/comparator is fully compatible with the tachometer and has a floating transistor as its output.
This feature allows either a ground or supply referred load of up to 50 mA.
The collector may be taken above VCC up to a maximum VCE of 28V.
The two basic configurations offered include an 8-pin device with a ground referenced tachometer input and an internal connection between the tachometer output and the op amp non-inverting input.
This version is well suited for single speed or frequency switching or fully buffered frequency to voltage conversion applications.
The more versatile configurations provide differential tachometer input and uncommitted op amp inputs.
With this version the tachometer input may be floated and the op amp becomes s...
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