The Introduction to LM2907

LM2907 is a single-chip frequency voltage converter with a high-gain operational amplifier/comparator. It is used to operate relays, lights or other loads when the input frequency reaches or exceeds the selected rate. 

The tachometer uses charge pump technology and provides double frequency low ripple. The output of the two versions of full input protection (LM2907-8, LM2917-8) 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 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.

Both of these configurations are available with an active shunt regulator connected across the power leads. The regulator clamps the supply such that stable frequency to voltage and frequency to current operations are possible with any supply voltage and a suitable resistor.

Symbol

Footprint

3D Model

●Direct ground reference tachometer input interface

●With variable reluctance sensor

●Operational amplifier/comparator with floating transistor output

●50 mA receiver or power supply, used to operate relays, solenoids, meters or LED low-ripple Y frequency multiplier

●The tachometer has built-in hysteresis, with differential input or ground reference input

●Built-in Zener LM2917

●G0.3% typical linearity

●The ground reference tachometer is fully protected from damage caused by swinging above the VCC and below the ground

Texas Instruments LM2907M technical specifications, attributes, parameters and parts with similar specifications to Texas Instruments LM2907M.

●Output Swings to Ground For Zero Frequency Input

●Easy to Use

●Only One RC Network provides Frequency Doubling

■ Overspeed/low speed sensing

■ Frequency-voltage conversion (tachometer)

■ Speedometer

■ Breaker point stay meter

■ Handheld tachometer

■ Governor cruise control

■ Car door lock control

■ Clutch control

■ Horn control

■ Touch or sound switch

Breaker Point Dwell Meter

Minimum Component Tachometer Diagram

Zener Regulated Frequency to Voltage Converter

Speed Switch

Texas Instruments (TI) is an American technology company headquartered in Dallas, Texas, which designs and manufactures semiconductors and various integrated circuits, and sells them to electronic designers and manufacturers worldwide. It is one of the top 10 semiconductor companies in global sales. The company focuses on the development of analog chips and embedded processors, which account for more than 80% of its revenue. TI also produces TI digital light processing technology and educational technology products, including calculators, microcontrollers and multi-core processors. As of 2016, the company has 45,000 patents worldwide.