Analog Devices Inc. AD977ABRZ

Overview

AD977ABRZ from Analog Devices is a 16-bit, 200 kSPS successive-approximation analog-to-digital converter (ADC) operating from a single 5 V supply. It features factory-calibrated linearity, on-chip 2.5 V reference, high-speed serial interface, and power-down mode consuming only 50 µW. It supports ±10 V, ±5 V, and 0 V–5 V input ranges and is used in precision industrial data acquisition systems requiring high DC accuracy and AC performance.

For engineers reviewing the AD977ABRZ datasheet, AD977ABRZ pinout, AD977ABRZ application, or AD977ABRZ equivalent, key selection considerations include throughput rate (200 kSPS), integral linearity error (±3 LSB max), full-power bandwidth (1 MHz), serial data format (binary two's complement or straight binary), and SOIC-20 package compatibility with legacy AD977-series layouts.

Technical Context

The AD977ABRZ implements a switched-capacitor SAR architecture with internal clock generation and dual-mode serial interface-supporting both internal DATACLK (EXT/INT = LOW) and external clock synchronization (EXT/INT = HIGH) with SYNC framing. Its conversion control relies on R/C and CS signals, with BUSY indicating active conversion state.

It integrates a 2.48 V–2.52 V internal reference (1 µA source current) and accepts external references from 2.3 V to 2.7 V. Input sampling capacitance is 40 pF, aperture delay is fixed at 40 ns, and transient response to full-scale step is 1 µs-enabling accurate capture of fast-changing sensor or process signals in closed-loop control.

Key Specifications

Pinout & Package

AD977ABRZ is housed in a 20-lead skinny SOIC (SOIC-20) package with standard 0.3-inch body width and 0.050-inch lead pitch. Thermal resistance θ_JA = 75°C/W enables operation up to +85°C ambient without forced airflow.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit SAR ADC applications.

Compared with AD7606BSTZ and ADS8860IDRCT, the AD977ABRZ uniquely combines single-supply 5 V operation, factory-calibrated bipolar/unipolar input flexibility, and internal 2.5 V reference in a compact SOIC-20-making it ideal for cost-sensitive, single-channel precision measurement where layout area and supply simplicity are critical.

Availability

AD977ABRZ is available at Aetrix Electronics and suitable for industrial process monitoring, automated test equipment, scientific instrumentation, and energy metering applications requiring stable component supply and long-lifecycle support.

Supply support for AD977ABRZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, founded in 1965 and headquartered in Wilmington, MA.

The AD977 family belongs to Analog Devices' precision data acquisition product line, designed specifically for applications demanding high DC accuracy, low power, and flexible analog input configuration in harsh industrial and laboratory environments.

FAQ

What is the maximum sampling rate supported by the AD977ABRZ?

The AD977ABRZ supports a maximum throughput rate of 200 kSPS, corresponding to a complete conversion cycle time of 5 µs. This is confirmed in Table 2 of the Rev. E datasheet under AD977A specifications. The AD977ABRZ achieves this rate while maintaining full 16-bit resolution, ±3 LSB INL, and 83 dB S/(N+D) performance at 20 kHz input frequency. Its 1 MHz full-power bandwidth ensures accurate digitization of signals well beyond Nyquist for typical industrial sensor bandwidths.

Does the AD977ABRZ require an external reference voltage?

No, the AD977ABRZ does not require an external reference voltage because it integrates a precision 2.48 V–2.52 V internal reference with 1 µA source capability. However, it also supports external reference inputs from 2.3 V to 2.7 V via the REF pin, allowing system-level voltage alignment or metrology-grade traceability. When using the internal reference, a 2.2 µF tantalum capacitor must be connected between CAP and AGND2 to ensure stability and low drift, as specified in the Pin Function Descriptions section.

How does the AD977ABRZ handle bipolar versus unipolar input configurations?

The AD977ABRZ supports both bipolar (±10 V, ±5 V, ±3.3 V) and unipolar (0 V–10 V, 0 V–5 V, 0 V–4 V) input ranges through external resistor networks connected to R1IN, R2IN, and R3IN pins, as detailed in Table 8 of the datasheet. The SB/BTC pin selects data format: LOW for two's complement (bipolar) or HIGH for straight binary (unipolar). Zero-error specifications differ-bipolar zero error is ±10 mV max, unipolar zero error is ±10 mV max-ensuring consistent offset performance regardless of range selection.

Can the AD977ABRZ be used in daisy-chained multi-ADC systems?

Yes, the AD977ABRZ supports daisy-chained operation via its TAG and SYNC pins in external clock mode (EXT/INT = HIGH). The TAG input level is output on DATA after 16–17 DATACLK periods, enabling time-aligned data from multiple AD977ABRZ devices to share a single serial bus. SYNC provides frame synchronization aligned to the external clock edge, ensuring deterministic readout timing across the chain. This capability is explicitly documented in Figures 7–12 and the "Use of the TAG Input" section of the datasheet.

What is the power consumption profile of the AD977ABRZ in active and power-down modes?

The AD977ABRZ consumes a maximum of 100 mW during active conversion (IDIG = 4 mA, IANA = 11 mA at 5 V), and drops to just 50 µW in power-down mode (PWRD = HIGH), as specified in Table 3. Recovery to full accuracy after exiting power-down takes ≤1 ms when a 2.2 µF capacitor is connected to CAP. This ultra-low standby power enables use in battery-backed data loggers and energy-harvesting systems where duty-cycled acquisition is employed without sacrificing measurement repeatability.