Overview
The LM2907M-8/NOPB is a frequency-to-voltage converter produced by Texas Instruments. This monolithic integrated circuit is designed to convert input frequencies into proportional output voltages, making it highly versatile for various applications. The device features a high-gain operational amplifier and a tachometer circuit that can operate with ground-referenced or differential input signals. It is particularly suited for applications requiring frequency measurement and conversion, such as speedometers, tachometers, and control systems.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Package Type | SOIC-8 | - |
| Supply Voltage | -28 to 28 | V |
| Output Sink Current | 50 | mA |
| Operating Temperature Range | -40 to 85 | °C |
| Storage Temperature Range | -65 to 150 | °C |
| Input Threshold Voltage | ±10 to ±40 | mV |
| Hysteresis | 30 | mV |
| Linearity | ±0.3% (Typical) | - |
| Thermal Resistance (Junction-to-Ambient) | 110 | °C/W |
Key Features
- Ground-referenced tachometer input interfaces directly with variable reluctance magnetic pickups.
- Op amp with floating transistor output capable of sinking or sourcing up to 50 mA to operate relays, solenoids, meters, or LEDs.
- Frequency doubling for low ripple output.
- Built-in hysteresis with either differential or ground-referenced input.
- High linearity of ±0.3% (typical).
- Full protection against voltage swings above VCC and below ground.
- Output voltage proportional to input frequency (VOUT = fIN × VCC × R1 × C1).
- Zener regulator on chip for accurate and stable frequency-to-voltage or current conversion.
Applications
- Over- and under-speed sensing.
- Frequency-to-voltage conversion (tachometer).
- Speedometers.
- Breaker point dwell meters.
- Hand-held tachometers.
- Speed governors.
- Cruise control.
- Automotive door lock control.
- Clutch control.
- Horn control.
- Touch or sound switches.
Q & A
- What is the primary function of the LM2907M-8/NOPB?
The primary function is to convert input frequencies into proportional output voltages. - What types of input signals can the LM2907M-8/NOPB handle?
The device can handle both ground-referenced and differential input signals. - What is the maximum output current of the LM2907M-8/NOPB?
The device can sink or source up to 50 mA. - What is the typical linearity of the LM2907M-8/NOPB?
The typical linearity is ±0.3%. - What is the operating temperature range of the LM2907M-8/NOPB?
The operating temperature range is -40°C to 85°C. - What types of applications is the LM2907M-8/NOPB suitable for?
It is suitable for speedometers, tachometers, speed governors, cruise control, and other frequency measurement and control applications. - How is the output voltage of the LM2907M-8/NOPB calculated?
The output voltage is calculated as VOUT = fIN × VCC × R1 × C1. - Does the LM2907M-8/NOPB have built-in protection against voltage swings?
Yes, it has full protection against voltage swings above VCC and below ground. - What is the purpose of the Zener regulator in the LM2907M-8/NOPB?
The Zener regulator ensures accurate and stable frequency-to-voltage or current conversion. - What package types are available for the LM2907 series?
The LM2907 series is available in SOIC-8, PDIP-8, and PDIP-14 packages.
