AD7740

The AD7740 is a low-cost, ultrasmall synchronous Voltage-to-Frequency Converter (VFC). It works from a single 3.0 V to 3.6 V or 4.75 V to 5.25 V supply consuming 0.9 mA. The AD7740 is available in an 8-lead SOT-23 and also in an 8-lead microSOIC package. Small package, low cost and ease of use were major design goals for this product. The part contains an on-chip 2.5 V bandgap reference but the user may overdrive this using an
external reference. This external reference range includes V_DD.

The full-scale output frequency is synchronous with the clock signal on the CLKIN pin. This clock can be generated with the addition of an external crystal (or resonator) or supplied from a CMOS-compatible clock source. The part has a maximum input frequency of 1 MHz. For an analog input signal that goes from 0 V to VREF, the out-put frequency goes from 10% to 90% of fCLKIN. In buffered mode,the part provides a very high input impedance and accepts a range of 0.1 V to V_DD 0.2 V on the VIN pin.

There is also an unbuffered mode of operation that allows VIN to go from0.15 V to VDD + 0.15 V. The modes are interchangeable using the BUF pin. The AD7740 (Y Grade) is guaranteed over the automotive temperature range of 40°C to +105°C. The AD7740 (K Grade) is guaranteed from 0°C to 85°C.