Texas Instruments ADC121S021CIMF/NOPB

Overview

ADC121S021CIMF/NOPB from Texas Instruments is a single-channel, 12-bit successive-approximation register (SAR) analog-to-digital converter with internal track-and-hold, operating from 2.7 V to 5.25 V supply and delivering 50–200 ksps sample rates. It features SPI/QSPI/MICROWIRE-compatible serial interface, 72.3 dB typical SNR, and 2.6 µW shutdown power. Used in portable instrumentation for precision sensor digitization.

For engineers reviewing the ADC121S021CIMF/NOPB datasheet, ADC121S021CIMF/NOPB pinout, ADC121S021CIMF/NOPB application, or ADC121S021CIMF/NOPB equivalent, key selection considerations include guaranteed performance across 50–200 ksps (not just at one rate), low-power shutdown mode, straight-binary output format, industrial temperature range (–40°C to 85°C), and SOT-23-6 package compatibility with space-constrained PCB layouts.

Technical Context

The ADC121S021CIMF/NOPB implements a charge-redistribution SAR architecture with an integrated track-and-hold circuit that samples VIN on the falling edge of CS and holds during conversion. Its control logic synchronizes acquisition, conversion, and 16-cycle serial readout via SCLK, with three leading zero bits followed by 12 data bits output on SDATA.

Functional mode switching is controlled solely by CS timing: normal mode initiates on CS low and persists if CS remains low past the 10th SCLK falling edge; shutdown mode activates if CS is pulled high between the 2nd and 10th SCLK falling edges, disabling analog circuitry and reducing supply current to 500 nA.

Key Specifications

Pinout & Package

ADC121S021CIMF/NOPB is packaged in a 6-pin SOT-23 (DBV) package with 2.90 mm × 1.60 mm body size, optimized for compact PCB layouts and reflow-compatible assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822IDR, ADC121S021CIMF/NOPB provides 4× higher resolution for calibrated sensor interfaces; compared with ADC121S051CIMF/NOPB, it offers verified 50 ksps operation essential for energy-constrained sampling, making it the only option among the three supporting full-range low-speed precision digitization.

Availability

ADC121S021CIMF/NOPB is available at Aetrix Electronics and suitable for portable instrumentation, remote data acquisition, and industrial sensor interface applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for ADC121S021CIMF/NOPB 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

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision data converters and industrial-grade IC design.

The ADC121S021CIMF/NOPB belongs to TI's precision SAR ADC product line, engineered for low-power, high-accuracy digitization in space- and energy-constrained systems such as handheld test equipment and distributed sensor nodes.

FAQ

What is the guaranteed sample rate range for ADC121S021CIMF/NOPB?

The ADC121S021CIMF/NOPB is fully specified from 50 ksps to 200 ksps - meaning all key parameters including INL, DNL, SNR, and THD are guaranteed across this entire range, not just at discrete points. This eliminates interpolation uncertainty in variable-throughput designs and supports robust timing budgeting in real-time systems where sample rate may be dynamically adjusted.

Does ADC121S021CIMF/NOPB require external reference voltage?

No, ADC121S021CIMF/NOPB uses its VA supply pin as the reference - the full-scale input range is 0 V to VA. This eliminates need for external reference components, reduces BOM count, and simplifies layout. However, VA must be clean and well-bypassed (1 µF + 0.1 µF) since any noise or ripple on VA directly modulates conversion accuracy and SNR.

How does the shutdown mode of ADC121S021CIMF/NOPB work?

ADC121S021CIMF/NOPB enters shutdown mode when CS is pulled high between the 2nd and 10th falling edges of SCLK after CS goes low. In shutdown, analog circuitry powers down, reducing supply current to 500 nA (typical) and total power to 2.6 µW at 5.25 V. Recovery requires pulling CS low again, with first conversion post-wakeup invalid and second valid - enabling predictable low-power burst sampling.

Is ADC121S021CIMF/NOPB pin-compatible with other devices in the ADC121S family?

Yes, ADC121S021CIMF/NOPB is fully pin- and function-compatible with ADC121S051CIMF/NOPB and ADC121S101CIMF/NOPB per TI's Device Comparison Table. All share identical SOT-23-6 pinout, interface protocol, and power sequencing - allowing drop-in replacement when higher sample rates (200–500 ksps or 500 ksps–1 Msps) are needed without PCB redesign.

What is the output data format of ADC121S021CIMF/NOPB?

ADC121S021CIMF/NOPB outputs straight binary (natural binary) format: three leading zero bits followed by twelve data bits, MSB first, clocked out on SCLK falling edges. This eliminates sign-extension or offset-binary decoding overhead in host firmware and ensures direct compatibility with standard SPI peripherals expecting unsigned integer data streams.