Product Summary
The LM2917N-8 is a monolithic frequency to voltage converter 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 LM2917N-8 uses a charge pump technique and offers frequency doubling for low ripple, full input protection in two versions (LM2907-8, LM2917-8) 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 applications of the LM2917N-8 include Over/under speed sensing, Frequency to voltage conversion (tachometer), Speedometers, Breaker point dwell meters, Hand-held tachometer, Speed governors, Cruise control, Automotive door lock control, Clutch control, Horn control, Touch or sound switches.
Parametrics
LM2917N-8 absolute maximum ratings: (1)Supply Voltage: 28V; (2)Supply Current (Zener Options): 25 mA; (3)Collector Voltage: 28V; (4)Differential Input Voltage Tachometer: 28V; Op Amp/Comparator: 28V; (5)Input Voltage Range Tachometer: 0.0V to +28V; Op Amp/Comparator: 0.0V to +28V; (6)Power Dissipation: 1200 mW; (7)Operating Temperature Range: -40℃ to +85℃; (8)Storage Temperature Range:-65℃ to +150℃; (9)Soldering Information Dual-In-Line Package Soldering (10 seconds): 260℃; (10)Small Outline Package Vapor Phase (60 seconds): 215℃; Infrared (15 seconds): 220℃.
Features
LM2917N-8 features: (1)Ground referenced tachometer input interfaces directly with variable reluctance magnetic pickups; (2)Op amp/comparator has floating transistor output; (3)50 mA sink or source to operate relays, solenoids, meters, or LEDs; (4)Frequency doubling for low ripple; (5)Tachometer has built-in hysteresis with either differential input or ground referenced input; (6)Built-in zener on LM2917; (7)±0.3% linearity typical; (8)Ground referenced tachometer is fully protected from damage due to swings above VCC and below ground.
Diagrams
Image | Part No | Mfg | Description | Pricing (USD) |
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LM2917N-8 |
National Semiconductor (TI) |
Voltage to Frequency & Frequency to Voltage |
Data Sheet |
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LM2917N-8/NOPB |
National Semiconductor (TI) |
Voltage to Frequency & Frequency to Voltage FREQ TO VLTG CONVERTER |
Data Sheet |
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