Analog Devices Inc. AD7777ARZ

Overview

AD7777ARZ from Analog Devices is a 4-channel, 10-bit successive-approximation register (SAR) analog-to-digital converter with parallel digital interface, ±1 LSB relative accuracy, 380.95 kSPS maximum sampling rate, and integrated 2.0 V reference output-designed for high-speed data acquisition in DSP-based voice recognition and adaptive filtering systems.

For engineers reviewing the AD7777ARZ datasheet, AD7777ARZ pinout, AD7777ARZ application, or AD7777ARZ equivalent, this page delivers verified electrical specs, channel-isolation performance, power-down timing, bus interface timing constraints, and real-world microprocessor interfacing guidance for TMS320 and ADSP-210x families.

Technical Context

The AD7777ARZ implements a track-and-hold architecture supporting up to 189 kHz input sine-wave bandwidth at full throughput. Its dual-conversion mode (CR6 = 1) enables simultaneous sampling across two selected channels with sequential conversion, while internal bias generation ties VBIAS directly to REFIN voltage.

Control register configuration (CR0–CR9) governs channel selection (AIN1–AIN4), single/dual conversion mode, half-scale test, power-down activation (CR8), and BUSY/INT functional mode (CR9). All logic inputs comply with TTL/CMOS thresholds, and REFOUT provides a 2.0 V ±0.1 V nominal output with 5 Ω typical DC impedance.

Key Specifications

Pinout & Package

AD7777ARZ is housed in a 28-lead SOIC (RW-28) package with exposed pad thermal enhancement. Pin functions are validated per Analog Devices Rev. A datasheet Figure on page 4 (28-Lead PDIP and SOIC top view) and Pin Function Description table (page 5).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit SAR ADC applications.

Compared with AD7777ARZ, AD7824JRZ trades resolution and reference integration for lower unit cost, while ADS8325IPW sacrifices channel count and interface speed to achieve 16-bit precision-neither offers simultaneous sampling or internal REFOUT, making AD7777ARZ uniquely suited for time-correlated multi-channel DSP acquisition.

Availability

AD7777ARZ is available at Aetrix Electronics and suitable for voice recognition front-ends, adaptive echo cancellation systems, and industrial sensor data loggers requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for AD7777ARZ 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 AD777x family was designed specifically for high-speed, multi-channel data acquisition in real-time DSP applications-including voice processing, adaptive filtering, and industrial control-where timing correlation, low distortion, and integrated reference stability are critical.

FAQ

What is the maximum sampling rate supported by the AD7777ARZ?

The AD7777ARZ supports a maximum sampling rate of 380.95 kSPS when CLKIN = 8 MHz. This corresponds to a single-conversion time of 14 tCLKIN (1.75 µs), plus acquisition time up to 5.5 tCLKIN + 70 ns. The device achieves this rate while maintaining –56 dB S/(N+D) and –60 dB THD performance at 99.88 kHz input frequency, as specified in the Rev. A datasheet.

Does the AD7777ARZ support simultaneous sampling across all four channels?

No, the AD7777ARZ supports simultaneous sampling on only two channels at a time, selected via control register bits CR0–CR2 (first channel) and CR3–CR5 (second channel). When CR6 = 1, it acquires both channels concurrently, then converts them sequentially-storing results in ADCREG1 and ADCREG2. Full 4-channel simultaneous sampling is not implemented in the AD7777ARZ architecture.

How does the AD7777ARZ handle power-down mode, and what happens to register contents?

Writing CR8 = 1 places the AD7777ARZ into power-down mode, immediately halting any active conversion and disabling all linear circuitry. REFOUT is weakly pulled to AGND (5 kΩ), and ICC drops to 1.5 mA max. Crucially, the contents of the control register and ADC registers (ADCREG1/ADCREG2) are retained during power-down and remain readable upon wake-up, enabling seamless resumption of operation without reconfiguration.

Can the AD7777ARZ operate with an external reference voltage, and what are the acceptable limits?

Yes, the AD7777ARZ accepts an external reference voltage on the REFIN pin, specified for 1.9 V to 2.1 V operation with nominal 2.0 V. This voltage directly sets VBIAS = REFIN and VSWING = REFIN/2, defining the analog input range as VBIAS ± VSWING (e.g., 1.0 V to 3.0 V for 2.0 V REFIN). Input current is ≤+200 µA, and input resistance exceeds 10 kΩ to AGND, per Rev. A datasheet Section "REFERENCE INPUT".

What microprocessors has the AD7777ARZ been validated to interface with, and what timing considerations apply?

The AD7777ARZ has been validated for direct parallel interface with TMS320C10/C14/C25 and ADSP-2101/2105 DSPs, including documented timing diagrams and wait-state configurations. Key constraints include t4 ≤ 60 ns (CS/RD active to valid data), t5 ≤ 45 ns (bus relinquish), and t3 ≥ 53 ns (WR pulsewidth), all tested with 100 pF load per Figure 4. These values ensure reliable handshaking without custom glue logic in standard 16-bit bus environments.