AD7740YRMZ-REEL7

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 MSOP 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 VDD. 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 V_REF, the output 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 VDD - 0.2 V on the VIN pin. There is also an unbuffered mode of operation that allows VIN to go from -0.15 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.

Applications

• Isolation of High Common-Mode Voltages
• Low-Cost Analog-to-Digital Conversion
• Battery Monitoring
• Automotive Sensing

Key features

• Synchronous Operation
• Full-Scale Frequency Set by External System Clock
• 8-Lead SOT-23 and 8-Lead MSOP Packages
• 3 V or 5 V Operation
• Low Power: 3 mW (Typ)
• Nominal Input Range: 0 to V_REF
• True -150 mV Capability Without Charge Pump
• V_REF Range: 2.5 V to VDD
• Internal 2.5 V Reference
• 1 MHz Max Input Frequency
• Selectable High Impedance Buffered Input
• Minimal External Components Required