ADC121S705CIMMX - 12-Bit 1MSPS Differential SAR ADC | TI
MPN: ADC121S705CIMMX ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.2 | $3.20 |
| 10 | $2.88 | $28.80 |
| 100 | $2.55 | $255.00 |
| 500 | $2.21 | $1,105.00 |
| 1,000 | $1.85 | $1,850.00 |
ADC121S705CIMMX Overview
A successive-approximation register (SAR) ADC is a sampling converter that uses a binary search through an internal capacitive DAC to resolve each conversion in N clock cycles for an N-bit code. Unlike delta-sigma converters, SAR ADCs provide a single conversion result per acquisition with no latency, deterministic timing, and inherently excellent AC/DC performance for multiplexed or sampled data systems. SAR ADCs sit within the broader data-converter hierarchy of analog-to-digital converters, which itself belongs to the data-acquisition IC and signal-chain semiconductor family, and they remain the workhorse for industrial control, instrumentation, and motor-drive applications where latency, sample-rate determinism, and DC accuracy matter most.
Key features of the ADC121S705CIMMX include 12-bit resolution, 1 MSPS maximum throughput, a fully differential analog input with high input impedance, an external reference that can swing from 1.0 V to VA for flexible input ranges, 244 uV LSB at VA = 1.0 V, and a low-power serial interface that simplifies galvanic isolation. The 8-VSSOP package has 3.00 mm width and supports the -40 C to +105 C industrial temperature range.
Architecturally, the device uses a charge-redistribution SAR core with a high-impedance differential input sample-and-hold, an external reference pin, and an SCLK-driven serial data output. The wide reference range allows scaling the input span to maximize dynamic range for low-amplitude transducer signals.
Typical applications include industrial process control, portable instrumentation, battery monitoring, motor control feedback, and remote sensor data acquisition. When designing with this ADC, use a low-noise analog supply, keep the reference bypassed with a 10 uF capacitor close to the REF pin, and route the serial clock and data lines away from switching nodes to preserve SNR.
Drop-in alternatives for ADC121S705CIMMX — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ADC121S705CIMMX (same form factor and footprint) — differing in Package, Resolution, Input Type, Operating Temperature Range, Number of Channels.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ADC121S705CIMM
✅ Drop-In📋 Reference alternative (not in catalog)
ADC121S705CIMM/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
ADC121S101CIMFX
✅ Drop-In✓ In Stock
$1.85 / Unit
View Datasheet →ADC121S051CIMFX
✅ Drop-In✓ In Stock
$1.95 / Unit
View Datasheet →ADC101S021CIMFX
✅ Drop-In✓ In Stock
$1.4 / Unit
View Datasheet →ADC121S705CIMMX Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Sample Rate (max) | 1 MSPS (500 kSPS to 1 MSPS) |
| Number of Channels | 1 |
| Converter Type | SAR (Successive Approximation) |
| Input Type | Differential |
| Analog Supply Voltage (VA) | 4.5 V to 5.5 V (5 V typical) |
| Digital Supply Voltage (VD) | 2.7 V to 5.5 V |
| Reference Voltage Range | 1.0 V to VA |
| LSB Size (VA = 1.0 V) | 244 uV |
| Output Format | Serial, 2's complement binary (SPI/QSPI/MICROWIRE/DSP compatible) |
| Operating Temperature | -40 C to +105 C |
| Package | 8-VSSOP (MSOP), 3.00 mm width |
| Mounting Type | Surface Mount |
| Linearity Error (max) | 0.0232% |
| RoHS Status | Compliant |
ADC121S705CIMMX Pin Configuration
| Pin 1 | CH0+ — Positive differential analog input |
| Pin 2 | CH0- — Negative differential analog input |
| Pin 3 | VA — Analog power supply (5 V typical) |
| Pin 4 | GND — Ground (analog and digital common) |
| Pin 5 | REF — External reference voltage input (1.0 V to VA) |
| Pin 6 | CS — Chip select (active low) |
| Pin 7 | SCLK — Serial clock input |
| Pin 8 | SDOUT — Serial data output (2's complement) |
Typical Applications
ADC121S705CIMMX is suitable for 6 applications: Industrial Process Control, Portable Instrumentation, Battery Monitoring Systems, Motor Control Feedback, Remote Sensor Data Acquisition, Medical Monitoring Devices.
Industrial Process Control
The ADC121S705CIMMX's 12-bit resolution, fully differential input, and 1 MSPS throughput make it well suited to industrial process-control loops where 4-20 mA or 0-10 V transducer signals must be digitized with high common-mode rejection. The wide reference range (1.0 V to VA) lets designers scale full-scale to the transducer output for maximum dynamic range. Its serial SPI output simplifies isolation through a digital isolator, keeping the analog front-end and noisy motor-drive ground planes separated. The -40 C to +105 C operating range covers factory-floor temperature requirements, and the 8-VSSOP footprint fits in compact PLC analog-input modules.
Recommended
Portable Instrumentation
The ADC121S705CIMMX's 5 V analog supply and 2.7 V to 5.5 V digital supply let it share rails with low-power microcontrollers, simplifying portable-instrument design. The high-impedance differential input is ideal for direct connection to bridge-type sensors (load cells, strain gauges) without external driver amplifiers. With 1 MSPS throughput, the ADC can oversample to improve effective resolution for handheld multimeters, dataloggers, and field-test equipment. The 8-VSSOP small footprint preserves PCB area for battery management and wireless radios, and the 2's complement serial output is directly compatible with common MCU SPIs.
Recommended
Battery Monitoring Systems
Battery-monitoring ICs and BMS front-ends require high-impedance, differential measurement of cell voltages with excellent DC accuracy. The ADC121S705CIMMX's differential input, 1 MSPS sample rate, and small 8-VSSOP package enable per-cell voltage telemetry in multi-cell battery packs. The external reference lets the designer use the same rail as the cell stack for ratiometric measurements, eliminating gain error from reference drift. The serial output is straightforward to route across an isolator for high-voltage traction-battery stacks. Operating from -40 C to +105 C, the ADC121S705CIMMX handles under-hood EV and grid-storage environments.
Recommended
Motor Control Feedback
Field-oriented control of BLDC and PMSM motors demands fast, deterministic current and position feedback. The ADC121S705CIMMX's 1 MSPS SAR architecture provides single-conversion latency (no pipeline delay), enabling tight current-loop control. Its differential input rejects switching noise from the inverter, and the wide reference range lets designers scale to shunt-resistor drops of 50-100 mV. Multiple ADC121S705CIMMX channels can be synchronized through the CS pin to sample all motor phases simultaneously, simplifying PCB layout. The 8-VSSOP package is small enough to place close to each phase shunt.
Recommended
Remote Sensor Data Acquisition
The ADC121S705CIMMX was designed for remote sensor data acquisition in battery-operated or energy-harvesting systems. Its low serial-interface pin count (CS, SCLK, SDOUT) minimizes the number of isolator or wireless channels needed, and the high-impedance differential input accepts direct bridge outputs without instrumentation amplifiers. The 244 uV LSB at 1 V reference provides 12-bit precision on low-amplitude signals, and the 5 V supply range is compatible with common industrial sensor rails. The 8-VSSOP package keeps the analog front-end footprint tiny for placement inside sensor housings.
Recommended
Medical Monitoring Devices
Patient-monitoring instruments such as pulse oximeters, ECG front-ends, and temperature dataloggers benefit from the ADC121S705CIMMX's differential input, 12-bit resolution, and low power consumption. The differential input rejects 50/60 Hz mains interference common in clinical environments, and the 1 MSPS throughput allows oversampling to improve effective resolution for low-amplitude biopotential signals. The 2's complement serial output simplifies digital filtering in a host DSP or MCU. The 8-VSSOP package fits in compact wearable form factors, and the wide operating temperature covers body-worn and bedside equipment.
Recommended
Recommended Products Summary
Engineering reference data for ADC121S705CIMMX — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ADC121S705CIMM | ADC121S705CIMM/NOPB | ADC121S101CIMFX | ADC121S051CIMFX | ADC101S021CIMFX |
|---|---|---|---|---|---|---|
| Package | 8-VSSOP (MSOP), 3.00 mm | 8-VSSOP (MSOP) - same | 8-VSSOP (MSOP) - same | 8-VSSOP (MSOP) - same | 8-VSSOP (MSOP) - same | 8-VSSOP (MSOP) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 10 bits |
| Max Sample Rate | 1 MSPS | 1 MSPS | 1 MSPS | 1 MSPS | 500 kSPS | 200 kSPS |
| Analog Supply | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V |
| Input Configuration | Differential | Differential | Differential | Single-ended | Single-ended | Single-ended |
| Reference | External, 1.0 V to VA | External, 1.0 V to VA | External, 1.0 V to VA | External, 1.0 V to VA | External, 1.0 V to VA | External, 1.0 V to VA |
| Output Format | Serial SPI 2's complement | Serial SPI 2's complement | Serial SPI 2's complement | Serial SPI straight binary | Serial SPI straight binary | Serial SPI straight binary |
Key Differentiators
- Fully differential input with high input impedance (vs ADC121S101CIMFX)
- Higher 1 MSPS throughput with same 8-VSSOP footprint (vs ADC121S051CIMFX)
- Tape-and-reel packaging (CIMMX suffix) (vs ADC121S705CIMM)
Design Notes
Bypass VA (pin 3) and VD (tied to VA in single-rail designs) with a 1 uF ceramic capacitor as close to the pin as possible, plus a 10 uF bulk capacitor on the analog rail. According to the TI ADC121S705 datasheet, REF (pin 5) should be decoupled with at least a 10 uF low-ESR capacitor to minimize reference-induced gain error. Estimated: with a 5 V supply and 1 MSPS conversion, the device draws a few mW of power, so a small LDO (such as TPS7A47 or LP2985) is sufficient as the analog source.
Place the input capacitors for CH0+ and CH0- close to the analog input pins and route the differential pair as a matched-length, ground-referenced pair to preserve common-mode rejection. Keep the REF capacitor within 5 mm of pin 5 and away from the digital SCLK/SDOUT traces. Use a single ground plane and place the ADC121S705CIMMX's GND pin directly to the analog ground pour via a short, low-inductance via. This layout is critical for preserving the 12-bit linearity and meeting the 0.0232% linearity error spec.
The SCLK line is the primary source of digital noise coupling into the analog input. Use a series 33 ohm damping resistor at the SCLK driver if the line length exceeds 25 mm, and keep SCLK rise/fall times below 5 ns where possible. SDOUT transitions should be sampled by the host MCU on the rising edge of SCLK to avoid setup/hold violations. According to the TI datasheet timing section, the maximum SCLK frequency is dictated by the sample rate and conversion latency, not by the device itself.
Compliance Information
RoHS compliant per TI product page and DigiKey listing. AEC-Q100 not applicable (industrial-grade part, -40 C to +105 C). Lead-free and halogen-free per the MSL/JEDEC J-STD-020 rating.
