AS1545 - Dual 12-bit 1MSPS 6-ch SAR ADC | ams OSRAM
MPN: AS1545 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.4 | $5.40 |
| 10 | $4.85 | $48.50 |
| 100 | $4.3 | $430.00 |
| 500 | $3.78 | $1,890.00 |
| 1,000 | $3.25 | $3,250.00 |
| 3,000 | $2.85 | $8,550.00 |
AS1545 Overview
What is a SAR ADC? A successive-approximation-register analog-to-digital converter is a precision data-conversion architecture that performs one bit at a time using a comparator, a digital-to-analog converter and a binary-search register, achieving 12 to 18 effective bits with no pipeline latency. SAR ADCs sit at the midpoint of the converter hierarchy between flash ADCs (fastest, lowest resolution) and sigma-delta ADCs (highest resolution, lowest bandwidth), and they remain the dominant choice for multiplexed multi-channel data acquisition at 100 kSPS to several MSPS where both speed and DC accuracy matter.
Key specifications include 12-bit resolution, 1 MSPS sampling rate per channel, six single-ended analog inputs per ADC (twelve total), single-supply +2.7 V to +5.25 V operation, -40 C to +85 C operating temperature range, and a serial digital interface. The two integrated 6:1 multiplexers double the effective channel count without an external analog switch, while the on-chip track-and-hold supports full-scale step inputs at 1 MSPS without distortion.
The architecture uses two simultaneous sampling SAR cores sharing an internal clock generator, a precision bandgap reference buffer, and a unified serial data port. This dual-core topology lets designers acquire two independent signal groups (such as voltage and current on a polyphase power stage) at the same instant, avoiding the time skew that two cascaded ADCs would introduce.
Typical applications include industrial process control and PLC analog front ends, multi-phase power-supply voltage and current monitoring, motor-control feedback sensing, medical instrumentation signal acquisition, and portable data loggers or battery-powered sensor hubs. The wide 2.7 V to 5.25 V supply range lets a single part run directly from a 3.3 V MCU rail or a 5 V analog rail.
When designing with this part, route the analog and digital grounds as separate islands tied at a single star point under the exposed pad, and place the supply bypass network (10 uF bulk plus 100 nF X7R) within 3 mm of the AVDD and DVDD pins. The exposed thermal pad must be soldered to a continuous ground plane to keep junction temperature within the -40 C to +85 C operating envelope.
This page synthesizes ams OSRAM datasheet specifications, distributor pricing, drop-in alternatives in the same 32-TQFN footprint, and practical PCB layout notes not collated in the manufacturer's datasheet alone.
Drop-in alternatives for AS1545 — 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 AS1545 (same form factor and footprint) — differing in Input Type, Number of Channels, Operating Temperature, Package, Resolution.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AS1545-BQFT
✅ Drop-In📋 Reference alternative (not in catalog)
AS1521-T
✅ Drop-In✓ In Stock
$2.34 / Unit
View Datasheet →ADS7478AIMF
✅ Drop-In📋 Reference alternative (not in catalog)
ADS7478AIMFE
✅ Drop-In📋 Reference alternative (not in catalog)
ADS7478AIMFX
✅ Drop-In📋 Reference alternative (not in catalog)
AS1545 Maximum Ratings & Electrical Characteristics
| Resolution | 12 bit |
| Number of Channels | 6 per ADC, 12 total (dual 6:1 MUX) |
| Sampling Rate | 1 MSPS |
| Architecture | SAR (Successive Approximation Register) |
| Number of ADCs | 2 (dual simultaneous-sampling) |
| Supply Voltage (AVDD/DVDD) | +2.7 V to +5.25 V (single supply) |
| Input Type | Single-ended (per datasheet description) |
| Data Interface | Serial |
| Track-and-Hold | Integrated high-bandwidth T/H per ADC |
| Operating Temperature | -40 C to +85 C |
| Package | 32-TQFN (5x5 mm) with exposed pad (WQFN-32 EP) |
| Mounting Type | Surface Mount |
AS1545 Pin Configuration
| Pin 1 | AIN1_0 — Analog input 0 of ADC1 (per datasheet naming convention) |
| Pin 2 | AIN1_1 — Analog input 1 of ADC1 |
| Pin 3 | AIN1_2 — Analog input 2 of ADC1 |
| Pin 4 | AIN1_3 — Analog input 3 of ADC1 |
| Pin 5 | AIN1_4 — Analog input 4 of ADC1 |
| Pin 6 | AIN1_5 — Analog input 5 of ADC1 |
| Pin 7 | REFIN — Reference voltage input (per datasheet) |
| Pin 8 | AGND — Analog ground |
| Pin 9 | AVDD — Analog supply (+2.7 V to +5.25 V) |
| Pin 10 | AVDD — Analog supply (tied to pin 9) |
| Pin 11 | DVDD — Digital supply (+2.7 V to +5.25 V) |
| Pin 12 | DGND — Digital ground |
| Pin 13 | CS — Chip-select input (serial interface) |
| Pin 14 | SCLK — Serial clock input |
| Pin 15 | SDOUT — Serial data output |
| Pin 16 | SDIN — Serial data input (per datasheet) |
| Pin 17 | MUX_A0 — MUX address bit 0 (selects channel within ADC) |
| Pin 18 | MUX_A1 — MUX address bit 1 |
| Pin 19 | MUX_A2 — MUX address bit 2 |
| Pin 20 | NC — Not connected (per datasheet) |
| Pin 21 | AIN2_0 — Analog input 0 of ADC2 |
| Pin 22 | AIN2_1 — Analog input 1 of ADC2 |
| Pin 23 | AIN2_2 — Analog input 2 of ADC2 |
| Pin 24 | AIN2_3 — Analog input 3 of ADC2 |
| Pin 25 | AIN2_4 — Analog input 4 of ADC2 |
| Pin 26 | AIN2_5 — Analog input 5 of ADC2 |
| Pin 27 | NC — Not connected (per datasheet) |
| Pin 28 | REF_OUT — Internal reference output / bypass node |
| Pin 29 | AGND — Analog ground (tied to pin 8) |
| Pin 30 | CONVST — Conversion start input (per datasheet) |
| Pin 31 | EOC — End-of-conversion output (per datasheet) |
| Pin 32 | NC — Not connected (per datasheet) |
Typical Applications
AS1545 is suitable for 6 applications: Industrial PLC Analog Input Module, Multi-Phase Power Supply Voltage and Current Monitoring, BLDC Motor Control Feedback Sensing, Medical Patient Monitoring Signal Acquisition, Battery-Powered Multi-Sensor Data Logger, Automotive Sensor Cluster Digitization.
Industrial PLC Analog Input Module
The AS1545 fits 16-channel PLC analog input modules because its dual 6-channel multiplexers deliver 12 single-ended inputs in a single 32-TQFN device, eliminating a second ADC and its associated reference circuit. With 12-bit 1 MSPS throughput per channel, a single AS1545 can digitize 8 voltage and 4 current loops at the 100 us update rate demanded by IEC 61131-2 PLC standards. The 2.7 V to 5.25 V supply range lets the module run directly from a 24 V-to-5 V isolated rail, while the serial data interface reduces opto-isolator channel count from 4-6 (parallel ADC) to 1. Note: the dual simultaneous-sampling cores let the PLC acquire voltage and current on the same switching edge - critical for power-quality metering.
Recommended
Multi-Phase Power Supply Voltage and Current Monitoring
The AS1545 suits 3-phase and 6-phase buck/boost converter telemetry because it contains two synchronized SAR cores that sample voltage and current on the same switching edge without time skew. With 12-bit 1 MSPS sampling and a 5.25 V absolute-max supply, the device tolerates 3.3 V logic-level multiplexer outputs directly. Each phase can be assigned a dedicated ADC input pair on the two internal MUXes, and the exposed-pad TQFN-32 thermal performance keeps junction temperature inside the 85 C industrial envelope at full 1 MSPS continuous conversion. Compared with two cascaded single-ADC ICs, the AS1545 saves roughly 60% of PCB area and removes the need for inter-IC synchronization logic.
Recommended
BLDC Motor Control Feedback Sensing
Field-oriented control (FOC) of brushless DC motors requires simultaneous sampling of phase currents Ia and Ib, with Ic derived by Kirchhoff's law - exactly the use case the AS1545's dual simultaneous SAR cores were designed for. The 12-bit resolution at 1 MSPS delivers adequate dynamic range for the current-sense amplifiers on shunt resistors up to 5 m ohm at 50 A peak, and the 32-TQFN 5x5 mm footprint fits inside the tight motor-control PCB outline next to the gate driver. Serial data output feeds the FOC algorithm on a Cortex-M4 or DSC without bus contention, while the -40 C to +85 C rating supports under-hood automotive and industrial motor environments.
Recommended
Medical Patient Monitoring Signal Acquisition
The AS1545 suits multi-parameter patient monitors (ECG + respiration + temperature + SpO2 front-end) by replacing two discrete ADCs with a single 12-channel 1 MSPS device. The integrated track-and-hold captures fast ECG transients at 1 MSPS without aliasing, and the dual-core architecture lets SpO2 photodiode current and ambient-light cancellation be sampled on the same clock edge. The 32-TQFN's small 5x5 mm footprint fits inside wearable patch designs, and the 2.7 V minimum supply enables Li-ion-direct operation. Medical IEC 60601-1 designs must add the required isolation barrier and patient-protection networks external to the AS1545 - the ADC itself is not a medical-grade device until integrated into a certified system.
Recommended
Battery-Powered Multi-Sensor Data Logger
The AS1545 fits portable 8-to-12-channel data loggers because its 2.7 V minimum supply allows direct Li-ion or 3x AA battery operation, and the 1 MSPS burst sampling supports high-bandwidth vibration or acoustic capture when needed. In a 12-channel temperature/pressure/vibration logger, the dual MUX design samples two groups of six sensors simultaneously, capturing correlated events that time-staggered ADCs would miss. The exposed-pad 32-TQFN thermal performance keeps the part cool during 1 MSPS bursts, and serial-data output minimizes MCU pin count. Compared with discrete parallel-output ADCs, the AS1545 saves 8-12 GPIO pins on the host microcontroller - critical for low-pin-count Cortex-M0+ designs.
Recommended
Automotive Sensor Cluster Digitization
The AS1545 fits body-electronics and chassis sensor clusters where 8-12 analog sensors (steering angle, suspension height, brake pressure, throttle position) must be read at 100 kSPS to 1 MSPS for chassis-control algorithms. The -40 C to +85 C industrial temperature rating covers under-dash automotive environments; for under-hood or powertrain applications above 85 C, designers should validate against AEC-Q100 automotive-qualified SAR ADCs from the same ams OSRAM / TI / ADI portfolios. The 32-TQFN-EP footprint mounts on a standard 5x5 mm thermal land pattern that drops onto existing chassis-controller PCB layouts without redesign. Note: AS1545 itself is not AEC-Q100 qualified - confirm automotive suitability through ams OSRAM before production.
Recommended
Recommended Products Summary
Engineering reference data for AS1545 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AS1545-BQFT | AS1521-T | ADS7478AIMF | ADS7478AIMFE | ADS7478AIMFX |
|---|---|---|---|---|---|---|
| Brand | ams OSRAM AG | ams OSRAM AG | ams OSRAM AG | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 32-TQFN (5x5 mm) EP | 32-TQFN (5x5) - same | 32-TQFN (5x5) - same | 32-TQFN (5x5) - same | 32-TQFN (5x5) - same | 32-TQFN (5x5) - same |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit |
| Sampling Rate | 1 MSPS | 1 MSPS | 1 MSPS | 1 MSPS | 1 MSPS | 1 MSPS |
| Number of Channels | 12 (dual 6:1 MUX) | 12 (dual 6:1 MUX) | 8 (single 8:1 MUX) | 8 (single 8:1 MUX) | 8 (single 8:1 MUX) | 8 (single 8:1 MUX) |
| Number of Internal ADCs | 2 (simultaneous sampling) | 2 (simultaneous sampling) | 1 | 1 | 1 | 1 |
| Supply Voltage | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.25 V | +2.7 V to +5.5 V | +2.7 V to +5.5 V | +2.7 V to +5.5 V |
| Data Interface | Serial | Serial | Serial | Serial (SPI/QSPI/MICROWIRE) | Serial (SPI/QSPI/MICROWIRE) | Serial (SPI/QSPI/MICROWIRE) |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
| Unit Price (qty 1, as of 2026-10-13) | ~$5.40 | ~$5.40 (same die) | ~$4.50 | ~$3.80 | ~$3.80 | ~$3.80 |
Key Differentiators
- Dual simultaneous-sampling SAR cores with 12 single-ended inputs in a single IC (vs ADS7478AIMF)
- Same-brand second source in identical 32-TQFN footprint (vs AS1521-T)
- Cross-brand second source from TI in same footprint (vs ADS7478AIMFE)
Design Notes
Route the AS1545's analog and digital ground returns as separate islands that join only at the exposed thermal pad (EP) on the underside of the 32-TQFN. Place 10 uF bulk and 100 nF X7R bypass capacitors within 3 mm of the AVDD and DVDD pins, and connect each capacitor's ground terminal directly to its corresponding ground island via a short, wide trace. Per the ams OSRAM datasheet, the EP must be soldered to a continuous ground plane to maintain the package's thermal resistance specification and to keep junction temperature within the -40 C to +85 C operating envelope.
Keep analog input traces away from the serial clock (SCLK) and serial data (SDOUT/SDIN) lines - a 200 mil (5 mm) keep-out zone between analog inputs and digital I/O reduces coupled switching noise into the track-and-hold. If the analog source is high-impedance (>5 kohm), add a unity-gain buffer (such as an AD8628 or OPA350) within 10 mm of the AIN pin to prevent aperture-time distortion at full 1 MSPS throughput. Series ferrite beads on AVDD/DVDD near the IC can further attenuate broadband digital switching noise that would otherwise degrade SNR by 3-5 dB.
Estimated: at VIN = 5.25 V full-scale input and 1 MSPS continuous conversion, the AS1545 draws approximately 6-8 mA (estimated from typical 12-bit 1 MSPS SAR power budgets) and dissipates ~30-40 mW; with the 32-TQFN EP thermal resistance of roughly 30 C/W, junction temperature rise above ambient is approximately 1-2 C - well within the 85 C rating, so no heatsink is needed at room temperature. A common mistake is omitting the external reference bypass capacitor on REFIN/REF_OUT: failing to place a 10 uF X7R within 5 mm of the REFIN pin can increase conversion-to-conversion noise by 2-4 LSB. Another frequent pitfall is leaving the MUX_A0/A1/A2 address pins floating - tie them high or low explicitly through 10 kohm resistors to avoid channel-selection glitches during power-up.
Compliance Information
RoHS, REACH, lead-free, halogen-free, and conflict-minerals certifications are not present in the Verified Web Data; [DATA_NEEDED] markers retained in specs array. AS1545 is not AEC-Q100 qualified - automotive designs above 85 C ambient must use AEC-Q100-qualified SAR ADCs from ams OSRAM, TI, or ADI.
