The LM2907N 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 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 50mA. 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 an 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 suitable for active filter conditioning of the tachometer output.
Feature
- Ground referenced tachometer input interfaces directly with variable reluctance magnetic pickups
- Op amp/comparator has floating transistor output
- 50mA 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
- ±0.3% Linearity typical
- Ground referenced tachometer is fully protected from damage due to swings above VCC and below ground
- Output swings to ground for zero frequency input
- Easy to use, VOUT = fIN x VCC x R1 x C1
- Only one RC network provides frequency doubling
- Green product and no Sb/Br
