CS5531ASEP - 16-bit Ultra-Low Noise PGIA ADC | Cirrus Logic
MPN: CS5531ASEP ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.08 | $3.08 |
| 10 | $2.95 | $29.50 |
| 100 | $2.72 | $272.00 |
| 500 | $2.5 | $1,250.00 |
| 1,000 | $2.3 | $2,300.00 |
CS5531ASEP Overview
A delta-sigma ADC uses oversampling and charge-balance (noise-shaping) techniques to achieve very high resolution from a modest sampling clock. According to the Cirrus Logic datasheet, the CS5531/32/33/34 family is highly integrated: the CS5531/33 provide 16-bit performance while the CS5532/34 provide 24-bit performance, all sharing the same architecture and package. Delta-sigma ADCs sit within the data acquisition hierarchy of analog front ends, alongside SAR and pipeline converters, and are preferred where precision at low bandwidth matters more than conversion speed.
Key features of the CS5531 include the integrated PGIA that accepts small differential sensor signals directly, a selectable gain range supporting bridge and load-cell front ends, multiple output word rates up to 3840 Hz, and an on-chip digital filter. The charge-balance modulator delivers low noise floor suitable for weighing scales, process transmitters, and precision instrumentation.
Technically, the device combines a 4th-order (family-typical) delta-sigma modulator with a digital decimation filter and self/system calibration options, allowing designers to remove offset and gain error without external trimming. The analog supply operates from 3 V to 5 V per distributor data, with a serial SPI-compatible interface (SCLK, SDI, SDO, CS) and multiplexed channel addressing for the two differential inputs.
Typical applications include industrial weighing scales and load-cell signal conditioning, precision process-control transmitters, and laboratory data acquisition front ends where the PGIA eliminates a separate instrumentation amplifier stage.
Design consideration: because delta-sigma converters sample continuously, ensure the serial interface timing and calibration routine are executed after power-up, and provide clean reference voltage decoupling for lowest noise.
This page synthesizes distributor pricing, same-family drop-in alternatives (CS5532/33/34), and practical design guidance not consolidated in the manufacturer datasheet.
Drop-in alternatives for CS5531ASEP — 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 CS5531ASEP (same form factor and footprint) — differing in Number of Input Channels, Package, Interface, Converter Type, Analog Supply Voltage.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
CS5531-ASZ
✅ Drop-In✓ In Stock
$3.98 / Unit
View Datasheet →CS5532-ASZR
✅ Drop-In✓ In Stock
$8.65 / Unit
View Datasheet →CS5532-BSZ
✅ Drop-In✓ In Stock
$4.03 / Unit
View Datasheet →CS5533-ASZ
✅ Drop-In✓ In Stock
$2.25 / Unit
View Datasheet →CS5533-ASZR
✅ Drop-In✓ In Stock
$3.55 / Unit
View Datasheet →CS5534-BSZ
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →CS5534-ASZR
✅ Drop-In✓ In Stock
$3.55 / Unit
View Datasheet →CS5531ASEP Maximum Ratings & Electrical Characteristics
| Resolution | 16 bit |
| Number of Input Channels | 2 (differential, multiplexed) |
| Converter Type | Sigma-Delta (charge-balance) |
| Max Output Word Rate | 3840 Hz |
| Analog Supply Voltage | 3 V to 5 V |
| Integrated Amplifier | Ultra-low-noise PGIA |
| Interface | SPI-compatible serial (SCLK, SDI, SDO, CS) |
| Package | SSOP-20 |
| Mounting Type | Surface Mount |
| Gain Selection | Programmable via PGIA |
| Calibration | Self and system calibration |
| Manufacturer | Cirrus Logic |
CS5531ASEP ssop-20 Pin Configuration Guide
Pin configuration for CS5531ASEP (ssop-20 package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for CS5531ASEP.
Refer to the datasheet for full pin configuration.
Typical Applications
CS5531ASEP is suitable for 6 applications: Weighing Scales and Load-Cell Front Ends, Industrial Process Transmitters, Precision Data Acquisition Systems, Medical Instrumentation Front Ends, Energy and Power Monitoring, Legacy Design Maintenance and Lifetime Buys.
Weighing Scales and Load-Cell Front Ends
The CS5531ASEP fits weighing-scale designs because its integrated ultra-low-noise PGIA amplifies the microvolt-level differential output of a Wheatstone-bridge load cell directly, removing a discrete instrumentation amplifier stage and its associated offset drift. The 16-bit charge-balance delta-sigma modulator delivers stable readings at retail-scale resolution counts, while self and system calibration trim offset and gain error over temperature. In a typical circuit the load cell connects differentially to the PGIA inputs, and the ADC runs at a low output word rate for maximum noise-free counts. Designers needing finer division counts can move to the pin-compatible 24-bit CS5532 on the same PCB footprint without layout changes.
Recommended
Industrial Process Transmitters
In 4-20 mA and smart process transmitters, the CS5531ASEP digitizes low-level sensor signals from pressure bridges and RTD front ends where noise floor and drift define accuracy. The PGIA gain selection lets one PCB serve multiple sensor ranges, reducing SKU count, and the SPI-compatible serial interface integrates easily with low-power MCUs common in loop-powered designs. Operating from a 3 V to 5 V analog supply per distributor data, the charge-balance converter rejects line-related interference at low word rates. The self-calibration routine executed at power-up keeps total error within transmitter accuracy budgets without manual trimming or costly reference trimming potentiometers.
Recommended
Precision Data Acquisition Systems
Laboratory and industrial data acquisition boards use the CS5531ASEP where 16-bit effective accuracy at modest bandwidth (up to 3840 Hz output word rate) is required, such as thermocouple, bridge, and low-frequency vibration inputs. The multiplexed two-channel differential architecture shares one PGIA and modulator across inputs, saving cost and board area versus per-channel converters. The digital decimation filter reduces external anti-aliasing requirements dramatically compared with SAR front ends. Because the CS5532/33/34 share the identical SSOP-20 pinout, a single DAQ PCB can be populated with 16-bit or 24-bit devices to create accuracy tiers from one layout.
Recommended
Medical Instrumentation Front Ends
Diagnostic and monitoring instruments measuring physiological signals through bridge or low-level transducers benefit from the CS5531ASEP's ultra-low-noise PGIA and high linearity delta-sigma conversion. The charge-balance architecture suppresses 50/60 Hz interference at appropriately chosen word rates, which is valuable in electrically noisy clinical environments. Its 3 V to 5 V analog supply range supports battery-powered portable devices, and the serial interface isolates cleanly with standard digital isolators for patient-connected equipment. For designs demanding finer resolution on weak bio-potential-adjacent signals, the pin-compatible 24-bit CS5532 substitutes without board redesign.
Recommended
Energy and Power Monitoring
Sub-metering and power-quality monitors sample current-shunt and voltage-divider signals with the CS5531ASEP, whose integrated PGIA accepts small shunt drops directly. The delta-sigma oversampling plus decimation filtering provides the anti-aliasing and noise performance needed for accurate RMS and power calculations at fundamental frequencies up to a few kilohertz. Two differential channels allow simultaneous-ish sampling of voltage and current paths through firmware-controlled multiplexing, sufficient for single-phase metering. The self-calibration feature removes gain and offset drift between production units, tightening billing-grade accuracy over temperature and component tolerance spreads.
Recommended
Legacy Design Maintenance and Lifetime Buys
For existing products designed around the CS5531ASEP, maintaining production requires sourcing discontinued parts from authorized aftermarket channels such as Rochester Electronics or qualifying same-family substitutions. Because the entire CS5531/32/33/34 family shares the SSOP-20 pinout, a board last purchased with CS5531 can be requalified with CS5532-ASZR or CS5533-ASZ with firmware-level verification only - no PCB respin. This page's cross-reference comparison and stocking guidance support obsolescence management, helping engineers quantify which family member is the lowest-risk substitution before placing a final lifetime-buy order.
Recommended
Recommended Products Summary
Engineering reference data for CS5531ASEP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | CS5531-ASZ | CS5532-ASZR | CS5533-ASZ | CS5534-BSZ |
|---|---|---|---|---|---|
| Package | SSOP-20 | SSOP-20 - same | SSOP-20 - same | SSOP-20 - same | SSOP-20 - same |
| Brand | Cirrus Logic | Cirrus Logic | Cirrus Logic | Cirrus Logic | Cirrus Logic |
| Resolution | 16 bit | 16 bit | 24 bit | 16 bit | 24 bit |
| Max Output Word Rate | 3840 Hz | 3840 Hz | 3840 Hz | 3840 Hz | 3840 Hz |
| Integrated PGIA | Yes (ultra-low-noise) | Yes | Yes | Yes | Yes |
| Analog Supply | 3 V to 5 V | 3 V to 5 V | 3 V to 5 V | 3 V to 5 V | 3 V to 5 V |
| Lifecycle Status | Obsolete (aftermarket only) | Aftermarket/distributor stock | Active at distributors | Aftermarket/distributor stock | Aftermarket/distributor stock |
Key Differentiators
- Integrated ultra-low-noise PGIA eliminates external instrumentation amplifier (vs CS5532-ASZR)
- Same-footprint 24-bit upgrade path (vs CS5532-ASZR)
- Trade-off: obsolescence risk vs alternatives (vs CS5532-ASZR)
Design Notes
Keep the analog front end physically separated from the digital SPI lines: route SCLK/SDI/SDO away from the PGIA input traces and the reference pins. Place 100 nF ceramic decoupling capacitors directly at the analog supply and reference pins, with a bulk 10 uF nearby. A solid analog ground plane under the ADC, joined to digital ground at a single point, minimizes return-current coupling into the charge-balance modulator and protects the noise floor that motivated choosing this family.
The CS5531 requires its calibration and configuration command sequence after power-up before conversion data is valid; designs that read the ADC immediately at reset will see offset errors. Also verify the register map and serial word format when substituting a CS5532 for a CS5531 - they are pin-compatible but the 24-bit data width and some command details differ. Finally, since the CS5531ASEP suffix is obsolete, screen broker-sourced parts for provenance; prefer Rochester Electronics or factory-marked distributor stock.
At low output word rates the delta-sigma filter averages many modulator samples, so input filtering requirements are modest - a simple RC (e.g., 1 k ohm and 100 nF) differential filter at the PGIA inputs handles most RF ingress. However, clock quality on XIN matters: jitter or a noisy crystal circuit raises the noise floor. Use a crystal with proper load capacitors per the datasheet and keep the oscillator traces short and guarded by ground.
Compliance Information
The verified web data does not state RoHS/REACH status for the CS5531ASEP suffix. The CS5531-ASZ Z-suffix conventionally indicates lead-free, but this must be confirmed with the manufacturer before compliance claims.
