IC-Mart Your Trusted Source for Voltage to Frequency & Frequency to Voltage Chips

(from leading manufacturers)

Leading Manufacturers and Representative V/F & F/V Converter Models

1. Texas Instruments (TI)

• LM331 / LM231 / LM131:​ The industry’s “gold standard.” Known for high precision and low cost, these asynchronous V/F converters can also be configured for F/V operation with external circuitry.
• LM2907 / LM2917:​ Designed specifically for automotive dashboards and motor speed sensing. Featuring a built-in high-gain op-amp, they can directly drive loads and are commonly used for F/V conversion.
• VFC32 / VFC320:​ Originally Burr-Brown models; utilize a charge-balancing architecture with extremely high linearity (0.01%) and support bidirectional conversion.
• VFC110:​ A high-speed V/F converter with a full-scale frequency up to 4 MHz, suitable for high-bandwidth signal processing.

2. Analog Devices (ADI)

• AD650:​ An asynchronous converter with exceptional linearity (0.1% linearity at 1 MHz full-scale), often used in precision integrated circuit testing.
• AD654:​ A low-cost, single-supply V/F converter requiring minimal external components (just one resistor and one capacitor).
• AD652:​ A Synchronous V/F Converter (SVFC) that requires an external clock, eliminating system errors caused by capacitor temperature drift.
• AD7740 / AD7741 / AD7742:​ Modern CMOS synchronous V/F chips. Compact and designed for microcontroller interfaces, supporting low-power 3V/5V systems.

3. Microchip Technology (Including former TelCom)

• TC9400 / TC9401 / TC9402:​ General-purpose V/F and F/V converters. The TC9400 is a highly classic model often found in low-cost digital voltmeters or frequency counter front-ends.
• This series supports single-supply operation and serves as a common alternative or reference for the LM331.

4. Nisshinbo Micro Devices (Formerly JRC)

• NJM4151:​ Based on the classic 4151 architecture. While its precision is slightly lower than the LM331, it remains popular in audio processing and simple FM monitoring applications.

5. MaxLinear (Including former Exar)

• XR4151:​ A classic model from Exar, representing an older generation of general-purpose V/F converters still required for maintaining legacy equipment.

China Domestic Manufacturers

• ① SG Micro (SGM):​ Strength lies in Op-Amps, ADCs, and analog interfaces. Currently, no standardized V/F ICs exist. Alternative path: Implementing V/F using Op-Amp + Comparator + MCU.
• ② CHIPSEA (CS):​ Strength lies in ADCs, MCUs, and sensor interfaces. V/F function is achieved via MCU/ADC + timer implementations. Common solution: CSU32 series MCUs (software-based V/F).
• ③ HDSC (Huada Semiconductor):​ Strength lies in industrial MCUs and mixed-signal analog. No independent V/F ICs. Solution: MCU + Timer output frequency.

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1. What are V/F and F/V Converter Chips?

Voltage-to-Frequency Converter (V/F Converter, VFC)

A V/F converter transforms an input analog voltage (Vin​) into a pulse train (fout​) where the frequency is proportional to the voltage.

• Logic:​ The higher the input voltage, the denser (faster) the output square wave or pulse stream.
• Mathematical Relation:​ fout​=k⋅Vin​(where kis the conversion gain).

Frequency-to-Voltage Converter (F/V Converter, FVC)

An F/V converter performs the reverse operation, transforming an input frequency signal (fin​) into a corresponding analog voltage (Vout​).

• Logic:​ The faster the pulse rate, the higher the output DC voltage.
• Mathematical Relation:​ Vout​=k′⋅fin​.

2. Typical Application Scenarios

Due to the superior noise immunity of frequency signals compared to analog voltages, these chips are widely used in industrial control and signal transmission.

A. Long-Distance Signal Transmission (Strength of V/F)

In harsh industrial environments (e.g., concrete pump trucks, heavy machinery), transmitting analog voltage signals over long cables leads to severe distortion due to line resistance and EMI.

• Solution:​ Use a V/F converter at the sensor end to convert voltage into frequency pulses for transmission via optocouplers or cables. Frequency signals are robust; even if noise interferes, accurate pulse counting preserves the data integrity.

B. Motor Speed Monitoring (Strength of F/V)

This is a classic application. Rotating equipment (e.g., automotive engines, fans, industrial conveyors) typically uses magnetic or optical sensors to generate pulses proportional to rotational speed (RPM).

• Solution:​ Use an F/V chip to convert the speed pulses into a DC voltage. This voltage can directly drive dashboard gauges or be fed into a controller (PLC) as a feedback signal for speed regulation.

C. High-Resolution A/D Conversion

For high-resolution measurements where speed is not critical (e.g., precision weighing, temperature monitoring), a V/F converter can serve as a cheap yet powerful Analog-to-Digital Converter (ADC).

• Solution:​ Paired with a microcontroller counter, the number of pulses output by the V/F converter within a specific time window can be counted to achieve extremely high-precision digital values.

D. Frequency Demodulation (FM Demodulation)

In radio or communication fields, information is often carried by frequency variations (FM signals).

• Solution:​ An F/V converter can directly demodulate the varying frequency back into the original analog audio or data signal.

Classification of Voltage to Frequency (V/F) & Frequency to Voltage (F/V) Chips

1. Classification by Basic Conversion Function

This is the most intuitive classification, determining whether the chip acts as an “analog input interface” or a “frequency signal demodulator.”

Category	Typical Chip Model	Primary Manufacturer	Application Logic
Unidirectional V/F Converter	AD7741, AD654	Analog Devices (ADI)	Converts sensor voltage to pulses for noise-immune transmission.
Unidirectional F/V Converter	LM2907, LM2917	Texas Instruments (TI)	Typically used in tachometers to convert speed signals into voltage.
Bidirectional Universal Converter	LM331, TC9400, VFC32	TI, Microchip	Classic general-purpose type; can switch between V/F or F/V modes via external circuits.

2. Classification by Clock Synchronization Logic

This distinguishes between “high precision” and “low cost” technical architectures.

Category	Typical Chip Model	Primary Manufacturer	Logic Characteristics
Asynchronous Converter	LM331, AD650, XR4151	TI, ADI, MaxLinear	Internal oscillator; frequency determined by external RC components. Low cost and flexible.
Synchronous Converter	AD7740, AD7742, AD652	Analog Devices (ADI)	Conversion controlled by an external system clock. Eliminates errors from external capacitor temp drift; offers extremely high linearity.

3. Classification by Circuit Topology Architecture

Determines the signal processing refinement and stability range.

Category	Typical Chip Model	Primary Manufacturer	Logic Characteristics
Charge-Balanced Type	VFC32, AD650, LM331	TI, ADI	Highest precision; suitable for precision instrumentation systems requiring >0.01% linearity.
Multivibrator Type	AD654, SN74LS624	ADI, TI	Simple structure, fast response, low power consumption, but linearity is generally inferior to charge-balanced types.

4. Classification by Output Full-Scale Frequency (Speed/Bandwidth)

Selection based on required signal bandwidth or dynamic range.

Category	Typical Chip Model	Primary Manufacturer	Logic Characteristics
Low/Medium Frequency Precision Type (≤100kHz)	TC9401, LM331, TC9400	Microchip, TI	Focuses on precision conversion of DC signals; common in industrial control.
Medium Frequency Type (500kHz – 1MHz)	VFC320, AD650	TI, ADI	Balances precision and speed.
High Frequency Type (1MHz – 10MHz)	VFC110, AD7741	TI, ADI	Suitable for fast signal acquisition, FM modulation, or motor closed-loop control systems.