AD7740KRMZ-REEL7

Overview

The AD7740KRMZ-REEL7 is a synchronous Voltage-to-Frequency Converter (VFC) from Analog Devices, housed in an 8-lead MSOP package. It operates on a single supply ranging from 3.0 V to 5.25 V with typical current consumption of 0.9 mA. The device features an internal 2.5 V bandgap reference and supports a maximum input frequency of 1 MHz. Integral Nonlinearity is specified at ±0.012% of span in unbuffered mode and ±0.018% in buffered mode. The K grade version guarantees operation within a temperature range of 0 °C to +85 °C.

Feature Summary

• Synchronous operation where full-scale output frequency is determined by the external system clock signal applied to the CLKIN pin.
• Selectable high impedance buffered input mode via the BUF pin, allowing for true bipolar operation down to -150 mV without requiring a charge pump.
• Minimal external component requirement as no resistors or capacitors are needed to set the output frequency; the part includes an automatic power-down function.
• Ratiometric design capability utilizing the internal 2.5 V reference or an overdriven external precision reference.

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 that the specific ordering suffix REEL7 corresponds to the tape and reel packaging configuration required for automated assembly processes. Confirm that the K grade designation aligns with the commercial temperature range specifications of 0 °C to +85 °C rather than the automotive Y grade. Ensure compatibility with the 8-lead MSOP footprint during PCB layout verification.

Selection Notes

Select this component when space constraints favor an ultrasmall surface-mount package over larger alternatives. Choose the AD7740 for applications requiring low power consumption and simplified circuit design due to the absence of external frequency-setting components. Consider the buffered versus unbuffered input modes based on source impedance requirements and the need for negative voltage input capability.

Part Context

This device belongs to the AD7740 series of synchronous voltage-to-frequency converters manufactured by Analog Devices Inc. The series emphasizes cost-effectiveness and ease of use through CMOS technology and charge-balance conversion techniques. The product line offers flexibility through different package options and temperature grades to suit various industrial and consumer electronics environments.

Replacement Considerations

AD7740KRMZ

FAQ

How does the AD7740 handle inputs below ground potential?

In unbuffered mode (BUF = 0), the analog input VIN can accept signals down to -0.15 V relative to ground, enabling true bipolar operation without the need for a charge pump circuit.

What determines the full-scale output frequency of the converter?

The full-scale output frequency is synchronous with the clock signal on the CLKIN pin. It can be generated by an external crystal connected between CLKIN and CLKOUT or supplied directly by a CMOS-compatible clock source.