VFC32KU

Overview

The VFC32KU is a voltage-to-frequency and frequency-to-voltage converter manufactured by Texas Instruments in a 14-pin SOIC package. It operates within a temperature range of 0°C to +70°C with a rated supply voltage of -15V (range -11V to -20V). The device features an open-collector digital output compatible with standard logic families. Key electrical specifications include a maximum full-scale frequency of 500kHz, a dynamic range of 6 decades, and a quiescent current of 5.5mA to 6.0mA. Linearity error is specified at -0.01% for frequencies up to 10kHz and -0.05% up to 100kHz.

Feature Summary

• Provides accurate voltage-to-frequency conversion with excellent linearity characteristics across a wide operating frequency range.
• Capable of bidirectional conversion, functioning as both a voltage-to-frequency and a frequency-to-voltage converter.
• Features an integrating input architecture that ensures high noise immunity and low nonlinearity.
• Delivers a digital open-collector frequency output compatible with common logic families.

Applications

• Integrating analog-to-digital converters
• Serial frequency output systems
• Isolated data transmission links
• FM analog signal modulation and demodulation
• Motor speed control circuits

Procurement Notes

Verify the specific suffix 'KU' corresponds to the SOIC-14 surface-mount package variant when sourcing replacements. Confirm the commercial temperature rating of 0°C to +70°C aligns with your environmental requirements. Ensure the -15V dual power supply configuration matches your system design, as this parameter is critical for proper operation.

Selection Notes

Select the VFC32KU when a surface-mount solution is required for voltage-to-frequency applications. This model offers a balance of precision and integration suitable for industrial environments. Consider external component selection carefully, particularly capacitors for setting full-scale frequency, as their tolerance directly impacts overall accuracy. Verify logic level compatibility for the open-collector output stage.

Part Context

The VFC32KU belongs to the VFC32 family of precision converters originally developed by Burr-Brown Corporation before its acquisition by Texas Instruments. This series includes variants such as the KP (DIP), BM (Metal TO-100), and SM (Military Metal) packages. The KU designation specifically identifies the commercial grade version housed in a standard SOIC-14 plastic surface-mount package.

Replacement Considerations

Direct substitutes within the same family include the VFC32KP (Plastic DIP) and VFC32BM (Metal TO-100). These parts share identical electrical specifications but differ in physical package dimensions and mounting style. Cross-package replacement requires PCB layout modifications to accommodate the different pin configurations and thermal properties.

FAQ

How is the full-scale output frequency determined?

The full-scale output frequency is determined by an external resistor and capacitor connected to the device. Specific values can be selected based on the desired frequency range using the manufacturer's capacitor value selection guidelines.

What type of output does the VFC32KU provide?

The device provides a digital open-collector frequency output. An external pull-up resistor is typically required to establish standard logic-level pulses, which can be connected to any power supply up to the positive supply rail (+VCC).

Can the VFC32KU operate as a frequency-to-voltage converter?

Yes, the VFC32KU can be configured as a frequency-to-voltage converter. This mode utilizes a capacitive-coupled input network to trigger the internal comparator, producing an analog voltage output proportional to the input frequency.