Overview
The VFC32KP, produced by Texas Instruments, is a voltage-to-frequency converter that provides an output frequency accurately proportional to its input voltage. This device is part of the VFC32 series and is available in various packages, including 14-pin plastic DIP, SO-14 surface-mount, and metal TO-100. It operates on the principle of charge balance, ensuring excellent linearity and noise immunity. The VFC32KP can also be configured as a frequency-to-voltage converter, making it versatile for different applications.
Key Specifications
| Parameter | Conditions | MIN | TYP | MAX | Units |
|---|---|---|---|---|---|
| Voltage Range (Positive Input) | >0, +0.25mA | 0 | 8 | 8 | V x R1 |
| Voltage Range (Negative Input) | >0 | -10 | 8 | 8 | V |
| Current Range | >0, +0.25mA | 0 | 8 | 8 | mA |
| Bias Current (Inverting Input) | 20 | 100 | 250 | nA | |
| Bias Current (Noninverting Input) | 100 | 250 | 250 | nA | |
| Offset Voltage | 1 | 4 | 8 | mV | |
| Differential Impedance | 300 || 10 | 650 || 10 | kΩ || pF | ||
| Common-mode Impedance | 300 || 3 | 500 || 3 | kΩ || pF |
Key Features
- Operation up to 500kHz
- Excellent linearity: ±0.01% max at 10kHz FS, ±0.05% max at 100kHz FS
- Voltage-to-frequency (V/F) or frequency-to-voltage (F/V) conversion
- Monotonic operation
- Voltage or current input
- Digital open-collector frequency output compatible with all common logic families
- Integrating input characteristics for excellent noise immunity and low nonlinearity
- Adjustable full-scale output frequency determined by external capacitor and resistor
Applications
- Integrating A/D converter
- Serial frequency output
- Isolated data transmission
- FM analog signal modulation/demodulation
- Motor speed control
- Tachometer
Q & A
- What is the maximum operating frequency of the VFC32KP?
The VFC32KP can operate up to 500kHz.
- What is the typical linearity error of the VFC32KP at 10kHz full-scale frequency?
The typical linearity error is ±0.01% at 10kHz full-scale frequency.
- Can the VFC32KP be used for both voltage-to-frequency and frequency-to-voltage conversions?
- What types of packages are available for the VFC32KP?
The VFC32KP is available in 14-pin plastic DIP, SO-14 surface-mount, and metal TO-100 packages.
- How is the full-scale output frequency determined?
The full-scale output frequency is determined by an external capacitor and resistor.
- What is the recommended duty cycle for best linearity?
A 25% duty cycle (0.25mA input current) is recommended for best linearity.
- Can the offset voltage be adjusted?
- What is the typical bias current for the inverting input?
The typical bias current for the inverting input is 100 nA.
- How does the VFC32KP handle noise immunity?
The VFC32KP has integrating input characteristics that provide excellent noise immunity and low nonlinearity.
- What are some common applications of the VFC32KP?
Common applications include integrating A/D converters, serial frequency output, isolated data transmission, FM analog signal modulation/demodulation, motor speed control, and tachometers.
