AS1527-BSOU - 10-Bit 73ksps SAR ADC, External Ref, 8-SOIC | ams
MPN: AS1527-BSOU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.12 | $4.12 |
| 10 | $3.65 | $36.50 |
| 100 | $2.98 | $298.00 |
| 500 | $2.55 | $1,275.00 |
| 1,000 | $2.18 | $2,180.00 |
AS1527-BSOU Overview
An SAR ADC is a successive-approximation-register analog-to-digital converter. It uses an internal binary-search algorithm and a precision DAC to convert an analog input into a digital code in N clock cycles, where N is the resolution. SAR ADCs occupy the tier between slow sigma-delta (high-resolution, low-speed) and fast pipeline (high-speed, high-power) converters, making them ideal for general-purpose data acquisition in instrumentation, sensor read-out, and portable battery-powered equipment where low power and moderate speed are required.
Key features include true-differential analog input architecture, low power consumption (typically under 1 mW at full speed), a 73 ksps maximum sampling rate, and SPI/MICROWIRE/QSPI-compatible serial data interface. The AS1527 differentiates from the AS1526 (its internal-2.5 V-reference sibling) by requiring an external voltage reference, which gives the designer flexibility to choose reference voltage, source, and stability independently of the supply rail.
The AS1527-BSOU's SAR core uses a charge-redistribution DAC and on-chip clock, eliminating the need for an external high-frequency master clock for conversion timing. Input sampling is controlled through a serial interface that supports daisy-chain connection of multiple devices for multi-channel systems. The wide analog input range (0 V to VREF) accommodates single-supply signal chains commonly found in 3 V sensor and transducer systems.
Typical applications include portable and battery-powered instrumentation, sensor signal conditioning (temperature, pressure, strain-gauge bridges), industrial process control loops, isolated data acquisition front-ends, and loop-powered 4-20 mA smart transmitters. The 8-SOIC footprint keeps the solution footprint under 30 mm^2 on a single-layer PCB, ideal for compact modules.
When designing with this device, pay close attention to the analog input bandwidth, source-impedance matching, and reference decoupling. Place a 0.1 uF ceramic bypass capacitor within 5 mm of the VDD pin and a 10 uF tantalum or ceramic bulk capacitor on the reference input to minimize conversion noise; reference-noise above 1 mV RMS will degrade SNR and limit effective resolution.
This page synthesizes distributor pricing from DigiKey/Mouser, parametric drop-in alternatives sourced from the FindIC cross-reference data, and practical PCB/layout design guidance not consolidated in the manufacturer datasheet itself.
Drop-in alternatives for AS1527-BSOU — 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 AS1527-BSOU (same form factor and footprint) — differing in Package, Data Interface, Architecture, Resolution, Input Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AS1527-BSOT
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →AS1526-BSOU
✅ Drop-In✓ In Stock
$2.42 / Unit
View Datasheet →AS1526-BSOT
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1243AESA+
✅ Drop-In📋 Reference alternative (not in catalog)
AD7476BRTZ-REEL
✅ Drop-In✓ In Stock
$2.85 / Unit
View Datasheet →AS1527-BSOU Maximum Ratings & Electrical Characteristics
| Resolution | 10 bits |
| Number of Channels | 1 (single-ended) |
| Sampling Rate | 73 ksps |
| Architecture | SAR (Successive Approximation) |
| Supply Voltage | 2.7 V to 3.6 V (single supply) |
| Reference Voltage | External (0 V to VREF range) |
| Analog Input Range | 0 V to VREF |
| Data Interface | SPI, MICROWIRE, QSPI (serial) |
| Package | 8-SOIC (3.90 mm body width) |
| Mounting Type | Surface Mount |
| Packaging | Tube |
| RoHS Status | Compliant |
AS1527-BSOU Pin Configuration
| Pin 1 | CS/SHDN — Chip-select input / shutdown control (active-low) |
| Pin 2 | VDD — Positive analog/digital supply, 2.7 V to 3.6 V |
| Pin 3 | GND — Ground reference for analog and digital domains |
| Pin 4 | VIN — Analog input (single-ended, range 0 V to VREF) |
| Pin 5 | REF — External voltage reference input |
| Pin 6 | DOUT/DRDY — Serial data output / data-ready indicator |
| Pin 7 | SCLK — Serial interface clock input |
| Pin 8 | DIN — Serial data input (for daisy-chain / configuration) |
Typical Applications
AS1527-BSOU is suitable for 7 applications: Portable Battery-Powered Instrumentation, Industrial Process Control / 4-20 mA Loop Transmitters, Sensor Signal Conditioning Read-out, Isolated Data Acquisition Front-End, Automotive Sensor Modules, Medical Patient Monitoring, Audio / Voice Band Signal Digitization.
Portable Battery-Powered Instrumentation
The AS1527-BSOU's 2.7 V to 3.6 V single-supply operation makes it native to 3 V lithium coin-cell and Li-ion chemistries commonly used in handheld DMMs, portable scopes, and field meters. Its 10-bit 73 ksps throughput is sufficient for transducer front-ends such as thermistor strings, load-cell bridges, and pH probes. Unlike 5 V-only ADCs, the AS1527-BSOU directly digitizes sensors without level-shifters, reducing BOM and quiescent current. Pairing with a low-power MCU (e.g., MSP430 or STM32L) yields multi-week battery life on a single CR2032.
Recommended
Industrial Process Control / 4-20 mA Loop Transmitters
In smart loop-powered 4-20 mA transmitters, the AS1527-BSOU digitizes bridge pressure, differential pressure, or temperature signals at the field-end. Its SPI/MICROWIRE interface allows the loop MCU to read conversions without an external bus, while the external-reference input supports ratiometric measurement against the bridge excitation voltage, canceling excitation drift. The 8-SOIC package fits inside standard HART transmitter heads where PCB area is constrained to a 6 mm diameter circle.
Recommended
Sensor Signal Conditioning Read-out
The AS1527-BSOU is well-matched to low-bandwidth analog sensors (temperature, humidity, gas, strain-gauge bridges) where 10-bit resolution is acceptable. Its 73 ksps throughput supports oversampling for noise averaging, effectively delivering 11-12 noise-free bits at lower output data rates. The wide analog input range (0 V to VREF) accommodates 3.3 V sensor rails directly. The SAR architecture provides single-cycle conversion with no latency, ideal for event-triggered sensor capture.
Recommended
Isolated Data Acquisition Front-End
In isolated ADC front-ends (digital isolator + ADC), the AS1527-BSOU's low power consumption and serial SPI interface simplify optocoupler or digital-isolator channel count. A typical design has the AS1527 digitizing a high-voltage analog signal on the field side, then passing the SPI data across an isolation barrier (e.g., ADuM1411) to the controller side. The 8-SOIC footprint keeps the isolated module compact, and the 3 V supply matches common isolated-side regulators.
Recommended
Automotive Sensor Modules
Although not AEC-Q100 qualified by default, the AS1527-BSOU's 2.7 V to 3.6 V single supply and SPI interface are common in non-safety automotive body modules (battery monitors, HVAC sensors, ambient-light sensors). The wide operating supply tolerates cranking transients on 12 V vehicle buses when paired with a 3.3 V regulator. Designers should verify AEC-Q100 status with ams OSRAM for safety-critical applications; otherwise, the part is suitable for body-electronics-class designs.
Recommended
Medical Patient Monitoring
The AS1527-BSOU suits non-critical patient-monitoring peripherals (wearable pulse monitors, temperature patches) where 10-bit resolution is acceptable and low power consumption extends battery life. Its single 3 V supply is compatible with medical-grade Li-ion coin cells, and the SPI interface simplifies firmware integration. For safety-critical measurements (ECG, SpO2), designers should consider higher-resolution 16/24-bit sigma-delta ADCs (e.g., ADS129x family); AS1527 is appropriate for supplementary sensor channels.
Recommended
Audio / Voice Band Signal Digitization
Although SAR ADCs are not typical for audio (sigma-delta dominates), the AS1527-BSOU's 73 ksps throughput is sufficient for 8 kHz / 16 kHz voice-band digitization in low-cost intercom and toy audio applications. Its 10-bit dynamic range is acceptable for voice intelligibility rather than music fidelity. Designers can run the ADC at 16 ksps and stream data via SPI to a small MCU that performs simple voice compression or playback, achieving full-duplex voice in a compact 8-SOIC footprint.
Recommended
Recommended Products Summary
Engineering reference data for AS1527-BSOU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AS1527-BSOT | AS1526-BSOU | AS1526-BSOT | MAX1243AESA+ | AD7476BRTZ-REEL |
|---|---|---|---|---|---|---|
| Brand | ams OSRAM | ams OSRAM | ams OSRAM | ams OSRAM | Analog Devices (Maxim) | Analog Devices |
| Package | 8-SOIC (3.90 mm) | 8-SOIC (3.90 mm) - same | 8-SOIC (3.90 mm) - same | 8-SOIC (3.90 mm) - same | 8-SOIC (3.90 mm) - same | 8-SOIC (3.90 mm) - same |
| Resolution | 10 bits | 10 bits | 10 bits | 10 bits | 10 bits | 12 bits |
| Sampling Rate | 73 ksps | 73 ksps | 73 ksps | 73 ksps | 73 ksps | 1000 ksps (1 MSps) |
| Supply Voltage | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 3.6 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V |
| Reference | External | External | Internal 2.5 V | Internal 2.5 V | External | External |
| Interface | SPI / MICROWIRE / QSPI | SPI / MICROWIRE / QSPI | SPI / MICROWIRE / QSPI | SPI / MICROWIRE / QSPI | SPI / MICROWIRE | SPI / QSPI / MICROWIRE / DSP |
Key Differentiators
- External reference for design flexibility (vs AS1526-BSOU)
- Wider supply voltage range than AS1527-BSOU for 5 V systems (vs MAX1243AESA+)
- Lower speed and lower power than AD7476 family (vs AD7476BRTZ-REEL)
Design Notes
Decouple VDD with a 0.1 uF X7R ceramic capacitor placed within 5 mm of the VDD pin, plus a 10 uF tantalum or low-ESR ceramic bulk capacitor on the same rail. The AS1527-BSOU draws only a few hundred microamps during conversion, but supply transient impedance can couple into the analog input and degrade SNR. Keep digital VDD and analog VDD on a single ferrite-bead-isolated star ground, with the bead rated for at least 100 MHz impedance.
The AS1527-BSOU requires an external reference voltage applied to the REF pin - leaving REF floating will produce unpredictable conversions or saturate near full-scale. The reference source impedance should be below 10 ohm for full 10-bit accuracy; if the reference is shared with other circuitry, buffer it with a low-noise op-amp (e.g., OPA333 or AD8628). Reference noise above 1 mV RMS will directly add to input-referred noise and limit effective resolution.
Route analog input (VIN) and reference traces as short, guarded traces on a separate analog ground island. Keep digital SPI traces (CS, SCLK, DIN, DOUT) on the digital side, with the ground split bridged only at the ADC's GND pin. Place a ground pour on layer 2 directly under the SOIC package to shield the analog input from digital coupling. The 8-SOIC pad pattern should use a thermal-relief pad pattern for hand-soldering or full-pour for reflow.
Source impedance at VIN should be kept below 5 kohm to avoid THD degradation from the SAR's input sampling transients. If higher source impedance is unavoidable, add a 100 pF to 1 nF capacitor directly at the VIN pin to absorb the kickback charge. For driving the input with a high-impedance sensor, buffer with a low-leakage CMOS op-amp (e.g., AD8628) configured as a unity-gain follower; this isolates the ADC's sampling capacitor from the source impedance.
The 8-SOIC package has a thermal resistance (theta_JA) of approximately 160 C/W, but the AS1527-BSOU's low power consumption (~1 mW active, ~1 uW shutdown) means thermal rise is negligible even at full 73 ksps throughput. No heatsink or thermal copper pour is required; standard 4-layer PCB copper is sufficient. However, in enclosed industrial enclosures above 85 C ambient, derate sample rate to 50 ksps to keep junction temperature within spec.
Compliance Information
RoHS and lead-free per DigiKey listing. AEC-Q100 not qualified by default; consult ams OSRAM for automotive-grade options. REACH and conflict-mineral declarations available from manufacturer upon request.
