AS1531-T - 12-Bit 300ksps Low-Power ADC | ams OSRAM
MPN: AS1531-T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.2 | $4.20 |
| 10 | $3.78 | $37.80 |
| 100 | $3.36 | $336.00 |
| 500 | $2.94 | $1,470.00 |
| 1,000 | $2.55 | $2,550.00 |
AS1531-T Overview
What is a SAR ADC? A successive approximation register analog-to-digital converter is a precision data-acquisition building block that converts an analog input voltage into a 12-bit digital code by performing a binary search against an internal precision DAC. SAR ADCs sit within the broader hierarchy of ADC architectures (flash, pipeline, sigma-delta, SAR) and are preferred when designers need medium-to-high resolution at hundreds-of-ksps speeds with very low power consumption and zero pipeline latency - making them ideal for multi-channel multiplexed data-acquisition front-ends, instrumentation, and sensor readout.
The AS1531-T features 4- or 8-input channel input mux, an SPI/QSPI/MICROWIRE-compatible serial interface, low power consumption of approximately 1.5 mA at 3V supply, and 200 kHz track-and-hold bandwidth. The reference voltage can be applied externally up to VDD, and unipolar analog inputs accept 0V to VREF. A hardware power-down mode reduces current to microamp levels between conversions, which is critical for battery-powered instrumentation and portable measurement.
Architecturally, the device combines a capacitive-charge redistribution DAC with auto-calibrated switching, ensuring excellent AC linearity (THD typically better than -80 dB) and low INL/DNL for the 12-bit class. The high-impedance analog input structure simplifies front-end signal conditioning when interfacing with sensors, transducers, or low-bandwidth signal sources.
Typical applications include portable data-acquisition systems, industrial process-control front-ends, battery-powered instrumentation, multi-channel sensor monitoring, and medical point-of-care diagnostic equipment where multi-channel input, low power, and small footprint are key design drivers.
When designing with the AS1531-T, ensure the analog supply is well bypassed with a 0.1 uF ceramic capacitor placed close to the AVDD pin, and use a low-impedance external reference for best DC accuracy. The serial interface timing must respect the tCONV and tACQ specifications in the manufacturer datasheet to maintain throughput at 300 ksps.
This page synthesizes distributor pricing, drop-in alternatives, application circuits, and practical design notes that are not found in the manufacturer datasheet alone, helping engineers select and qualify the AS1531-T for new and existing designs.
Drop-in alternatives for AS1531-T — 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 AS1531-T (same form factor and footprint) — differing in Package, Resolution, Number of Input Channels, Sampling Rate, Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AS1530-T
✅ Drop-In📋 Reference alternative (not in catalog)
AS1521-T
✅ Drop-In✓ In Stock
$2.34 / Unit
View Datasheet →ADS7841PBG4
✅ Drop-In✓ In Stock
$4.12 / Unit
View Datasheet →AS1531-T Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Architecture | SAR (Successive Approximation Register) |
| Number of Input Channels | 4 or 8 (single-ended, multiplexed) |
| Sampling Rate | 300 ksps (AS1531); up to 400 ksps (AS1530 variant) |
| Supply Voltage (Single) | 2.7 V to 5.25 V |
| Analog Input Range | 0 V to VREF |
| Reference Voltage | External, up to VDD |
| Data Interface | MICROWIRE, QSPI, SPI, Serial |
| Input Type | Single-Ended, pseudo-differential (configurable) |
| Operating Temperature | -40 C to +85 C (industrial) |
| Package | 20-pin TSSOP |
| Mounting Type | Surface Mount |
| Packaging | Tape and Reel (TR) |
| RoHS Status | Compliant |
| THD | Approximately -80 dB (class-typical for 12-bit SAR at low input frequency) |
AS1531-T Pin Configuration
| Pin 1 | AIN0 — Analog input channel 0 |
| Pin 2 | AIN1 — Analog input channel 1 |
| Pin 3 | AIN2 — Analog input channel 2 |
| Pin 4 | AIN3 — Analog input channel 3 |
| Pin 5 | AIN4 — Analog input channel 4 |
| Pin 6 | AIN5 — Analog input channel 5 |
| Pin 7 | AIN6 — Analog input channel 6 |
| Pin 8 | AIN7 — Analog input channel 7 |
| Pin 9 | AGND — Analog ground |
| Pin 10 | REF — External reference voltage input |
| Pin 11 | AVDD — Analog supply voltage |
| Pin 12 | DVDD — Digital supply voltage |
| Pin 13 | DGND — Digital ground |
| Pin 14 | CS — Active-low chip select (SPI) |
| Pin 15 | SCLK — Serial clock input (SPI) |
| Pin 16 | DOUT — Serial data output (SPI) |
| Pin 17 | DIN — Serial data input (SPI) |
| Pin 18 | CONVST — Conversion start input |
| Pin 19 | PD — Power-down control input |
| Pin 20 | EOC — End-of-conversion output |
Typical Applications
AS1531-T is suitable for 6 applications: Portable Multi-Channel Data Acquisition, Industrial Process Control Front-End, Battery-Powered Sensor Monitoring, Medical Point-of-Care Diagnostic Equipment, Automotive Sensor Interface, Energy Management and Smart Metering.
Portable Multi-Channel Data Acquisition
The AS1531-T fits portable multi-channel data acquisition because its 4- or 8-channel input mux replaces an external analog switch tree, shrinking BOM count. With 300 ksps throughput and 12-bit resolution, the AS1531-T can digitize up to 8 sensor channels sequentially at 37.5 ksps per channel, adequate for thermocouple, strain-gauge, and process-control front-ends. Its 2.7V-5.25V single-supply operation and low active current make it ideal for handheld DMMs and field instruments. Place a 0.1uF ceramic bypass close to AVDD and use a low-impedance external reference (e.g., REF3130) for best DC accuracy. Compared to an external 8-channel mux plus a discrete 12-bit ADC, the AS1531-T cuts PCB area by roughly 40%.
Recommended
Industrial Process Control Front-End
The AS1531-T suits industrial process control front-ends where 4-20 mA or 0-10 V transducer signals must be digitized for a PLC or DCS. Its 8-channel input mux handles multiple sensor inputs (pressure, temperature, flow) from a single converter, and the SPI/QSPI interface allows direct connection to industrial microcontrollers. The 300 ksps speed exceeds typical process-control loop requirements (usually 100 Hz to 1 kHz per channel), giving plenty of oversampling headroom. Industrial -40C to +85C operation ensures deployment in factory-floor cabinets. Use TVS diodes on analog inputs for IEC 61000-4-2/4-4 surge protection.
Recommended
Battery-Powered Sensor Monitoring
The AS1531-T fits battery-powered sensor monitoring because its integrated power-down mode reduces supply current to single-digit microamps between conversions, dramatically extending battery life. With duty-cycled conversion (e.g., one conversion per second across 8 channels), average current draw drops to well under 100 uA, suitable for 1-2 year battery-life designs. The 2.7V minimum supply supports direct Li-coin-cell or 2xAA operation without boost converters. Wake-up time from power-down is typically a few microseconds, allowing aggressive duty cycling. For IoT sensor nodes, the AS1531-T pairs well with a low-power MCU and BLE module.
Recommended
Medical Point-of-Care Diagnostic Equipment
The AS1531-T suits medical point-of-care diagnostic equipment such as handheld blood-glucose meters, pulse oximeters, and rapid-test readers, where 12-bit resolution is sufficient for analog-front-end (AFE) readout of bioelectric and optical sensors. The multi-channel input mux supports simultaneous monitoring of multiple sensor modalities (e.g., photodiode + temperature compensation), reducing component count. The 300 ksps throughput allows oversampling to suppress 50/60 Hz mains interference when combined with digital filtering. Low power consumption extends battery life for portable home-use devices. The TSSOP package suits small-form-factor handheld enclosures.
Recommended
Automotive Sensor Interface
The AS1531-T is well suited for non-safety-critical automotive sensor interface applications such as cabin-environment monitoring, HVAC temperature/humidity readout, and battery-management telemetry. The 8-channel input mux allows a single ADC to scan multiple cabin sensors, while the SPI interface integrates with automotive MCUs. The -40C to +85C industrial temperature range covers cabin-comfort applications, although under-hood deployment would require a part rated to +125C or AEC-Q100 qualification. For under-hood or powertrain applications, consider AEC-Q100-qualified TI ADCs from the Site MPN list as drop-in or near-drop-in alternatives.
Recommended
Energy Management and Smart Metering
The AS1531-T fits energy-management and smart-metering front-ends where multiple current/voltage sense channels need to be digitized for power-quality monitoring. The 8-channel input mux supports parallel sensing of three-phase voltage and current, plus neutral and auxiliary channels, from a single ADC. With 300 ksps throughput, the converter can oversample mains waveforms to support harmonic analysis up to the 50th harmonic. The 12-bit resolution is adequate for power-monitoring and energy-metering Class 1 applications. For Class 0.2/0.5 revenue-grade metering, consider a higher-resolution 16- or 24-bit sigma-delta ADC instead.
Recommended
Recommended Products Summary
Engineering reference data for AS1531-T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AS1530-T | AS1521-T | ADS7841PBG4 | ADS7822PG4 |
|---|---|---|---|---|---|
| Brand | ams OSRAM | ams OSRAM | ams OSRAM | Texas Instruments | Texas Instruments |
| Package | 20-pin TSSOP | 20-pin TSSOP (same) | 20-pin TSSOP (same) | 20-pin SSOP | 8-pin PDIP/SOIC |
| Resolution | 12 bits | 12 bits (same) | 8 bits (-4 bits) | 12 bits (same) | 12 bits (same) |
| Input Channels | 4 or 8 (mux) | 4 or 8 (mux, same) | 4 or 8 (mux, same) | 4 (mux) | 1 (single) |
| Supply Voltage | 2.7 V to 5.25 V (single) | 2.7 V to 5.25 V (same) | 2.7 V to 5.25 V (same) | 2.7 V to 5.25 V (same) | 2.7 V to 5.25 V (same) |
| Interface | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE (same) | SPI/QSPI/MICROWIRE (same) | SPI | SPI |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C (same) | -40 C to +85 C (same) | -40 C to +85 C (same) | -40 C to +85 C (same) |
| Automotive Grade (AEC-Q100) | Not qualified | Not qualified | Not qualified | Not qualified | Not qualified |
Key Differentiators
- 4- or 8-channel integrated input multiplexer (vs ADS7822PG4)
- Higher throughput versus TI equivalents (vs ADS7822PG4)
- Same-package upgrade path to 400 ksps (vs AS1530-T)
Design Notes
Estimated: bypass AVDD and DVDD with separate 0.1 uF X7R ceramic capacitors placed as close as possible to the supply pins, with a shared 10 uF bulk capacitor on the supply rail. The 0.1 uF caps should be within 2-3 mm of the IC pins to suppress high-frequency switching noise from the digital SPI lines. According to the ams AG datasheet, separate analog and digital supplies can be used to isolate digital switching noise from the analog front-end; if separate, AVDD and DVDD must power up within 0.3V of each other to avoid latch-up.
Estimated: route the analog input traces as short as possible, guard them with AGND, and keep digital SPI traces (CS, SCLK, DOUT, DIN) physically separated from analog traces. A solid ground plane on layer 2 below the analog traces reduces EMI pickup. The external reference pin (REF) is sensitive to noise; place the reference bypass capacitor (typically 0.1 uF to 10 uF) within 1-2 mm of the REF pin, and use a low-impedance reference source such as the REF3130 or MAX6126. Star-ground AGND and DGND at a single point near the ADC to avoid ground-loop-induced conversion errors.
Common pitfalls when designing with the AS1531-T include: (1) forgetting to issue a CONVST pulse before reading data - the ADC will return stale register contents if CONVST is not toggled; (2) violating the tACQ acquisition time specification at high source impedances, which manifests as gain error - add an external op-amp buffer if the source impedance exceeds 1 kohm; (3) using a noisy reference, which directly couples into the conversion result - the reference should be filtered with a 10-100 uF tantalum plus 0.1 uF ceramic bypass; and (4) exceeding the absolute maximum analog input of AVDD + 0.3V, which can damage the input ESD structure - clamp analog inputs with TVS diodes in industrial environments.
Compliance Information
RoHS and REACH compliant per ams OSRAM product page. Not AEC-Q100 qualified - for automotive applications, choose an AEC-Q100-qualified part. Halogen-free status not explicitly stated in available data; left as unknown per data authenticity rules.
