Analog Devices Inc. AD7440BRM

Overview

AD7440BRM from Analog Devices is a 10-bit, 1 MSPS successive approximation register (SAR) analog-to-digital converter with fully differential analog input, operating from single 3 V or 5 V supply, delivering 61 dB SINAD at 100 kHz input and supporting transducer interface in battery-powered data acquisition systems.

For engineers reviewing the AD7440BRM datasheet, AD7440BRM pinout, AD7440BRM application, or AD7440BRM equivalent, key selection considerations include its 8-lead SOT-23 package, differential track-and-hold architecture, SPI-compatible serial interface, 4 mW max power at 3 V/1 MSPS, and guaranteed no missed codes to 10 bits.

Technical Context

The AD7440BRM employs a SAR architecture with no pipeline delay, using a low-noise, wide-bandwidth differential track-and-hold amplifier capable of handling input frequencies up to 3.5 MHz. Its conversion is initiated on the falling edge of CS and synchronized to the SCLK, enabling precise sampling control.

It accepts an externally applied reference voltage (VREF) ranging from 100 mV to 2.2 V (at 3 V supply) or up to 3.5 V (at 5 V supply), directly setting full-scale span (2 × VREF) and common-mode input range. Output coding is twos complement, with 4 leading zeros followed by 10 data bits and 2 trailing zeros.

Key Specifications

Pinout & Package

AD7440BRM is housed in an 8-lead SOT-23 package (JEDEC MO-178AA), with gull-wing leads, 0.95 mm pitch, and 1.0 mm height. Thermal impedance θ_JA is 211.5°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7440BRM, AD7450ABRM offers higher resolution at the cost of increased power and slightly relaxed linearity, while ADS7822U trades speed and package size for lower unit cost and reduced power at sub-1 MSPS rates - making each suitable for distinct design priorities in embedded sensing.

Availability

AD7440BRM is available at Aetrix Electronics and suitable for transducer interface, battery-powered systems, and data acquisition systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for AD7440BRM 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with design centers worldwide and a legacy of precision data conversion innovation.

The AD7440BRM belongs to Analog Devices' high-speed, low-power SAR ADC product line, engineered specifically for portable and space-constrained applications demanding accuracy, efficiency, and differential noise immunity without sacrificing throughput.

FAQ

What is the maximum sampling rate supported by the AD7440BRM?

The AD7440BRM supports a maximum throughput rate of 1 MSPS, achieved with an 18 MHz serial clock (SCLK). At this rate, conversion time is fixed at 16 SCLK cycles (888 ns), and the device maintains full 10-bit accuracy with 61 dB SINAD at 100 kHz input frequency. Lower rates are achievable by reducing SCLK frequency, enabling power scaling in duty-cycled applications.

Does the AD7440BRM require an external reference voltage?

Yes, the AD7440BRM requires an external reference voltage applied to the VREF pin. For specified performance, VREF must be 2.0 V (±1%) with a 3 V supply or 2.5 V (±1%) with a 5 V supply. The reference can be scaled from 100 mV to 2.2 V (3 V supply) or up to 3.5 V (5 V supply), directly determining full-scale input span (2 × VREF) and common-mode range.

Is the AD7440BRM pin-compatible with the AD7450A?

Yes, the AD7440BRM and AD7450ABRM share identical 8-lead SOT-23 pinout, pin functions, and electrical interface specifications. Both use the same VREF, VIN+, VIN–, GND, CS, SDATA, SCLK, and VDD connections, and both output 16-bit frames (4 leading zeros + data + trailing zeros). Firmware and layout are interchangeable, though AD7450ABRM outputs 12-bit data instead of 10-bit.

What serial interface protocols does the AD7440BRM support?

The AD7440BRM supports SPI, QSPI, MICROWIRE, and DSP-compatible serial interfaces using a standard 3-wire configuration (CS, SCLK, SDATA). It operates in master-in/slave-out mode with data clocked out on the falling edge of SCLK, MSB first, and requires no mode pins or configuration registers - enabling plug-and-play integration with most microcontrollers and DSPs.

How does the AD7440BRM manage power consumption in low-duty-cycle applications?

The AD7440BRM features a full power-down mode drawing ≤1 µA, activated by holding CS high while SCLK is inactive. This allows rapid wake-up (<1 µs power-up time) between conversions, making it ideal for battery-operated systems that sample intermittently. Power scales linearly with throughput: at 100 kSPS, dissipation drops to ~0.6 mW (3 V), enabling multi-year operation on small batteries.