AD7740YRMZ Datasheet PDF - ADI

Product Details

●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 VREF, 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.

●Product Highlights

● 1. The AD7740 is a single channel, single-ended VFC. It is available in 8-lead SOT-23 and 8-lead MSOP packages, and is intended for low-cost applications. The AD7740 offers considerable space saving over alternative solutions.

● 2. The AD7740 operates from a single 3.0 V to 3.6 V or 4.75 V to 5.25 V supply and consumes typically 0.9 mA when the input is unbuffered. It also contains an automatic power-down function.

● 3. The AD7740 does not require external resistors and capacitors to set the output frequency. The maximum output frequency is set by a crystal or a clock. No trimming or calibration is required.

● 4. The analog input can be taken to 150 mV below GND for true bipolar operation.

● 5. The specified voltage reference range on REFIN is from 2.5 V to the supply voltage, VDD.

●Applications

● Isolation of high common-mode voltages

● Low-cost analog-to-digital conversion

● Battery monitoring

● Automotive sensing

●### Features and Benefits

● 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 VREF

● True –150 mV capability without charge pump

● VREF 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