Analog Devices Inc. AD7853LBR

Overview

AD7853LBR from Analog Devices is a 12-bit, 100 kSPS pseudo-differential successive-approximation ADC optimized for low-power operation on 3 V to 5.5 V single supply. It features on-chip 2.5 V reference, self- and system-calibration, flexible SPI/QSPI/8051-compatible serial interface, and 24-lead SOIC package. Used in battery-powered medical instruments and portable data acquisition systems.

For engineers reviewing the AD7853LBR datasheet, AD7853LBR pinout, AD7853LBR application, or AD7853LBR equivalent, key selection criteria include its 4.5 mW typical power dissipation at 3 V, 10 µs max conversion time, ±1 LSB integral nonlinearity, 0–VREF or ±VREF/2 input range support, and sleep-mode current of 5 µA with external clock off.

Technical Context

The AD7853LBR employs a charge-redistribution SAR architecture with integrated track-and-hold (500 ns acquisition), internal 2.5 V reference, and programmable analog input mode (unipolar/bipolar via AMODE). Calibration logic supports automatic power-up self-calibration and user-initiated system calibration using external reference inputs.

Its serial interface operates in five configurable modes (SM1/SM2 controlled), supporting both external-clock (SCLK input) and self-clocking (SCLK output) configurations with polarity control via POLARITY pin. The device retains calibration data during SLEEP mode and supports software-controlled conversion start via control register write.

Key Specifications

Pinout & Package

AD7853LBR is housed in a 24-lead SOIC (R-24) package with standard 0.3-inch width, gull-wing leads, and JEDEC MS-013AC footprint compatibility.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit, low-power SAR ADC applications.

Compared with AD7853BR and ADS7822U, the AD7853LBR uniquely balances sub-7 mW active power, integrated reference, and on-chip calibration - making it the only option that meets simultaneous requirements for 100 kSPS sampling, <10 µA sleep current, and zero-external-reference operation in portable instrumentation.

Availability

AD7853LBR is available at Aetrix Electronics and suitable for battery-powered medical instruments, portable data loggers, industrial field transmitters, and pen-based computing interfaces requiring stable component supply and long-term lifecycle support.

Supply support for AD7853LBR 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.

The AD7853LBR belongs to Analog Devices' precision SAR ADC product line, designed specifically for portable and power-constrained measurement systems requiring integrated calibration, low quiescent current, and robust serial interfacing.

FAQ

What is the maximum sampling rate supported by the AD7853LBR?

The AD7853LBR supports a maximum sampling rate of 100 kSPS, achieved with a 1.8 MHz master clock (CLKIN) at 0°C to +70°C or 1 MHz CLKIN over –40°C to +85°C. This fixed throughput is specified in the AD7853L datasheet and distinguishes it from the faster AD7853 variant. The AD7853LBR maintains this rate across its full operating temperature and supply range while delivering ±1 LSB integral nonlinearity performance.

Does the AD7853LBR require an external reference voltage?

No, the AD7853LBR does not require an external reference voltage because it integrates a 2.5 V internal reference accessible at the REFIN/REFOUT pin. However, it supports external reference override from 1.2 V to AVDD, enabling flexibility for systems needing tighter reference accuracy or different full-scale ranges. When using the internal reference, CREF1 (0.1 µF) and CREF2 (0.01 µF) capacitors must be connected to AGND per the AD7853LBR pinout and layout guidelines.

How does the AD7853LBR enter and exit low-power sleep mode?

The AD7853LBR enters sleep mode when the SLEEP pin is driven logic low, powering down all circuitry-including the internal reference-while retaining calibration data in nonvolatile registers. It exits sleep mode on the rising edge of SLEEP, requiring ~100 µs for reference stabilization before valid conversions. The AD7853LBR achieves 5 µA typical current draw with external clock disabled, making it suitable for intermittent-sampling applications like environmental data loggers.

Can the AD7853LBR perform system-level calibration with external components?

Yes, the AD7853LBR supports system-level calibration using its CAL pin and REFIN/REFOUT functionality. By applying a known external voltage to AIN(+) and AIN(–), users can execute system offset and gain calibration sequences that adjust for errors introduced by external signal conditioning circuitry. The AD7853LBR's calibration spans (+0.05 × VREF for offset, +1.025 × VREF/–0.975 × VREF for gain) define the correctable error range, and calibration results are stored in on-chip registers for persistent use.

What serial interface protocols does the AD7853LBR support?

The AD7853LBR supports SPI, QSPI, and 8051-compatible serial interfaces through five programmable modes selected by SM1 and SM2 pins. It operates with either external SCLK (modes 1–3) or self-clocking SCLK output (modes 4–5), and supports both CPOL/CPHA variants via the POLARITY pin. All modes use 16-bit frames (2 address + 14 data bits), and DOUT/DIN are three-state capable to enable multi-drop bus configurations - fully documented in the AD7853LBR timing diagrams and register map.