AD7740KRM

Overview

The AD7740KRM is a synchronous Voltage-to-Frequency Converter (VFC) manufactured by Analog Devices Inc. It operates from a single 3.0 V to 5.25 V supply and consumes typically 0.9 mA in normal mode. The device features an internal 2.5 V bandgap reference, with a full-scale frequency set by an external clock or crystal connected to the CLKIN pin. It supports a maximum input frequency of 1 MHz and offers selectable high-impedance buffered or unbuffered analog inputs. The K grade version guarantees operation within a temperature range of 0 °C to +85 °C.

Feature Summary

• Synchronous voltage-to-frequency conversion utilizing an external master clock for stable transfer functions without trimming.
• Integrated 2.5 V bandgap reference with capability for overdriving via external precision references.
• Selectable input buffering allowing true bipolar operation down to -150 mV below ground or high-impedance buffered mode.
• Automatic power-down activation upon inactive clock signals to minimize power consumption.

Applications

• Isolation of high common-mode voltages using opto-isolators
• Low-cost analog-to-digital conversion systems
• Battery monitoring circuits
• Automotive sensing applications

Procurement Notes

Verify the specific ordering suffix RM against the datasheet Ordering Guide to confirm the package type and RoHS compliance status. Ensure the required temperature grade matches the K specification for commercial ranges. Confirm that the application circuitry supports the single-supply voltage requirements and clock generation methods specified in the documentation.

Selection Notes

Select this component for applications requiring low-cost, space-saving voltage-to-frequency conversion. Consider the K grade for commercial temperature environments. Evaluate the need for buffered versus unbuffered input modes based on source impedance and voltage range requirements relative to the supply voltage.

Part Context

The AD7740 belongs to a family of synchronous VFCs designed for minimal external component counts. It utilizes charge-balance conversion techniques and integrates essential functions like clock generation and reference voltage sources into a compact footprint suitable for portable and industrial electronics.

Replacement Considerations

Cross-reference the AD7740YRM for automotive temperature range requirements (-40 °C to +105 °C). Verify pinout compatibility if substituting with other VFC devices, as package pin configurations may vary between manufacturers.