ADI AD7715ARZ-5

The AD7715 is a complete analog front end for low frequency measurement applications. The part can accept low level input signals directly from a transducer and outputs a serial digital word. It employs a Σ-Δ conversion technique to realize up to 16 bits of no missing codes performance. The input signal is applied to a proprietary programmable gain front end based around an analog modulator. The modulator output is processed by an on-chip digital filter. The first notch of this digital filter can be programmed via the on-chip control register allowing adjustment of the filter cutoff and output update rate.

The AD7715 features a differential analog input as well as a differential reference input. It operates from a single supply (3 V or 5 V). It can handle unipolar input signal ranges of 0 mV to 20 mV, 0 mV to 80 mV, 0 V to 1.25 V and 0 V to 2.5 V. It can also handle bipolar input signal ranges of ±20 mV, ±80 mV, ±1.25 V and ±2.5 V. These bipolar ranges are referenced to the negative input of the differential analog input. The AD7715 thus performs all signal conditioning and conversion for a single channel system.

The AD7715 is ideal for use in smart, microcontroller, or DSP-based systems. It features a serial interface that can be configured for three-wire operation. Gain settings, signal polarity, and update rate selection can be configured in software using the input serial port. The part contains self-calibration and system calibration options to eliminate gain and offset errors on the part itself or in the system.

CMOS construction ensures very low power dissipation, and power-down mode reduces the standby power consumption to 50 μW typical. The part is available in a 16-lead, 0.3 inch-wide, plastic dual-in-line package (PDIP) as well as a 16-lead 0.3 inch wide small outline (SOIC_W) package and a 16-lead TSSOP package.

• Charge-balancing ADC 16-bits no missing codes ±0.0015% nonlinearity
• Programmable gain front end Gains of 1, 2, 32 and 128 Differential input capability
• Three-wire serial interface
• SPI-, QSPI-, MICROWIRE-, and DSP-compatible
• Ability to buffer the analog input
• 3 V (AD7715-3) or 5 V (AD7715-5) operation
• Low supply current: 450 μA maximum @ 3 V supplies
• Low-pass filter with programmable output update
• 16-lead SOIC/PDIP/TSSOP

• Pressure Measurement
• Temperature Measurement
• Smart Transmitters