Analog Devices Inc. AD7484BSTZ

Overview

AD7484BSTZ from Analog Devices is a 14-bit, 3 MSPS successive approximation register (SAR) analog-to-digital converter with parallel interface, 40 MHz input bandwidth, internal 2.5 V reference, and full-scale overrange capability via 15th bit. It operates from a single 5 V supply and supports ±200 mV input offset for single-supply op amp interfacing in high-speed data acquisition systems.

For engineers reviewing the AD7484BSTZ datasheet, AD7484BSTZ pinout, AD7484BSTZ application, or AD7484BSTZ equivalent, key selection criteria include throughput rate (3 MSPS), dc accuracy (±1 LSB INL), power modes (90 mW / 2.5 mW / 2 µA), VDRIVE-adjustable digital interface, and 48-lead LQFP package compatibility with AD7482.

Technical Context

The AD7484BSTZ implements an algorithmic SAR architecture with no pipeline delay, using a capacitive DAC and internal trimmed oscillator to control conversion timing. Its track-and-hold acquires signals within 70 ns and handles input frequencies up to 40 MHz at 3 MSPS.

It features dual parallel interface modes (Mode 1 and Mode 2), configurable via MODE1/MODE2 pins, with BUSY signaling synchronized either to output latch (Mode 1) or conversion completion (Mode 2). The VDRIVE pin sets digital I/O voltage levels independently from AVDD/DVDD (2.7 V to 5.25 V).

Key Specifications

Pinout & Package

The AD7484BSTZ is housed in a 48-lead LQFP package (7 mm × 7 mm, 0.5 mm pitch) with exposed thermal pad, rated for −40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed SAR ADC applications.

Compared with AD7484BSTZ, AD7482BSTZ offers pin-compatible 12-bit performance at lower cost and power but sacrifices 6 dB SNR and 2-bit resolution; ADS8588SIPM delivers superior resolution and integrated features but requires PCB redesign and firmware changes due to SPI interface and larger footprint.

Availability

AD7484BSTZ is available at Aetrix Electronics and suitable for high-speed data acquisition, industrial motor control, medical ultrasound beamforming, and communications test equipment requiring stable component supply across extended temperature ranges.

Supply support for AD7484BSTZ 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, headquartered in Norwood, MA.

The AD7484BSTZ belongs to Analog Devices' high-speed precision SAR ADC product line, designed specifically for applications demanding deterministic latency, wide input bandwidth, and flexible power management in compact industrial and medical systems.

FAQ

What is the maximum input frequency the AD7484BSTZ can accurately digitize?

The AD7484BSTZ has a full-power bandwidth of 40 MHz at the −3 dB point, meaning it can accurately digitize sinusoidal inputs up to 40 MHz while maintaining specified SINAD and THD performance. At 1 MHz input, typical SINAD is 78 dB and THD is −95 dB, confirming high-fidelity capture well within its bandwidth limit. This makes the AD7484BSTZ suitable for digitizing fast transients and high-frequency sensor outputs without aliasing or amplitude loss.

Does the AD7484BSTZ require an external reference, or does it have an internal one?

AD7484BSTZ includes an internal 2.5 V reference with buffered output (REFOUT), calibrated to ±50 mV error at 25°C and ±100 mV over −40°C to +85°C. It also supports external 2.5 V references via REFIN. When using the internal reference, a 1 nF capacitor must connect REFSEL to AGND; when using external reference, REFSEL ties directly to AGND and a 470 nF capacitor connects REFIN to AGND. The internal reference eliminates BOM cost and board space in many applications.

How does the overrange capability of the AD7484BSTZ work, and what is its practical benefit?

The AD7484BSTZ provides 8% full-scale overrange via a dedicated D14 output bit, allowing accurate digitization of analog inputs up to −200 mV to +2.7 V - exceeding the nominal 0 V to 2.5 V range. When enabled, D14 acts as an overflow flag: logic high indicates input exceeds +2.5 V, logic low indicates input falls below 0 V. This prevents data corruption during signal transients (e.g., motor startup surges or ultrasound pulse echoes), enabling robust system operation without front-end clamping or gain adjustment.

Can the AD7484BSTZ interface directly with a 3.3 V microcontroller?

Yes, the AD7484BSTZ supports direct interfacing with 3.3 V microcontrollers via its VDRIVE pin, which sets digital I/O voltage thresholds independently from AVDD/DVDD. By connecting VDRIVE to 3.3 V, the logic high threshold becomes ~2.3 V (0.7 × VDRIVE) and logic low remains ≤0.4 V - fully compatible with standard 3.3 V CMOS levels. This eliminates external level shifters, reduces signal integrity risk, and simplifies PCB routing while maintaining full 3 MSPS throughput in Parallel Mode 2.

What are the power consumption differences between normal, nap, and standby modes of the AD7484BSTZ?

In normal operational mode, AD7484BSTZ consumes 20 mA (100 mW at 5 V); in nap mode, current drops to 0.5 mA (2.5 mW), retaining reference stability for fast wake-up; in standby mode, current is ≤2 µA (10 µW), powering down all circuitry except reset logic. Nap mode requires ≥300 ns settling before conversion if external reference is used; standby mode requires full reset initialization. These modes allow dynamic power scaling aligned to system activity - e.g., nap between bursts in intermittent DAQ, standby during idle periods.