AS1541-BQFT - 10-Bit 4-Ch I2C SAR ADC, 50ksps, 16-TQFN | ams OSRAM
MPN: AS1541-BQFT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.92 | $4.92 |
| 10 | $4.42 | $44.20 |
| 100 | $3.93 | $393.00 |
| 500 | $3.54 | $1,770.00 |
| 1,000 | $3.15 | $3,150.00 |
| 2,500 | $2.83 | $7,075.00 |
AS1541-BQFT Overview
A SAR ADC (Successive Approximation Register Analog-to-Digital Converter) is a precision data-conversion architecture that uses a binary-search algorithm against an internal precision DAC and comparator to resolve one bit per clock cycle. SAR ADCs are prized for low-latency conversions (no pipeline delay), intrinsic accuracy on a single conversion, low power, and excellent behavior for multiplexed multi-channel data acquisition in industrial, instrumentation, and sensor-conditioning applications.
Key features of the AS1541-BQFT include 10-bit resolution with no missing codes, an integrated 4-channel analog multiplexer, an I2C-compatible 2-wire serial interface supporting Standard-Mode (100 kHz) and Fast-Mode (400 kHz) operation, an on-chip track-and-hold, a 2.5V internal reference (with external reference option), and software-configurable unipolar input ranges. The 16-TQFN-EP package exposes a thermal pad that must be soldered to a grounded copper pour to meet the datasheet thermal specification.
The architecture combines a charge-redistribution DAC, a high-performance comparator, and a SAR control logic block. The I2C address is hardware-selectable through an AS pin, allowing up to two AS1541 devices to coexist on the same bus. Power-down modes reduce supply current to microampere levels between conversions for battery-friendly duty-cycled acquisition.
Typical applications include multi-channel sensor monitoring (temperature, pressure, strain gauge bridges), portable/battery-powered instrumentation, factory automation front-ends, HVAC controllers, programmable logic controller (PLC) analog input modules, and consumer device user-interface controls such as potentiometer or thermistor readout. The 4-channel multiplexer minimizes external analog switch count in multi-sensor systems.
When designing with the AS1541-BQFT, decouple AVDD and DVDD with 100 nF ceramic capacitors placed within 5 mm of the supply pins, keep analog and digital ground planes joined at a single point near the exposed pad, and drive the I2C lines with pull-up resistors sized for the chosen bus speed and total capacitance.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes that go beyond the manufacturer datasheet to help engineers evaluate the AS1541-BQFT for multi-channel precision data acquisition designs.
Drop-in alternatives for AS1541-BQFT — 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 AS1541-BQFT (same form factor and footprint) — differing in Data Interface, RoHS Status, Operating Temperature, Package, Sampling Rate.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AS1539-BQFT
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
ADS7822PBG4
✅ Drop-In✓ In Stock
$2.1 / Unit
View Datasheet →ADS7825PG4
✅ Drop-In✓ In Stock
$7.2 / Unit
View Datasheet →ADC121S021CISDX
✅ Drop-In✓ In Stock
$1.85 / Unit
View Datasheet →ADS7824PG4
✅ Drop-In✓ In Stock
$11.1 / Unit
View Datasheet →ADS7828KPZ-REEL
✅ Drop-In📋 Reference alternative (not in catalog)
AS1541-BQFT Maximum Ratings & Electrical Characteristics
| Resolution | 10 bits |
| Number of Input Channels | 4 (single-ended) |
| Converter Type | SAR (Successive Approximation Register) |
| Sampling Rate | 50 ksps |
| Data Interface | I2C (Standard 100 kHz / Fast 400 kHz) |
| Analog Supply Voltage | 2.7 V to 5.25 V |
| Supply Current (typ) | 1.5 mA at 50 ksps |
| Internal Reference | 2.5 V |
| External Reference Support | Yes |
| Input Configuration | Single-ended, software-selected via MUX |
| Package | 16-TQFN (4x4 mm) with exposed pad |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Track-and-Hold | On-chip |
| Hardware Address Select | Yes (AS pin, supports 2 addresses) |
| Power-Down Mode | Yes (software-controlled) |
AS1541-BQFT Pin Configuration
| Pin 1 | AIN0 — Analog input channel 0 (single-ended) |
| Pin 2 | AIN1 — Analog input channel 1 (single-ended) |
| Pin 3 | AIN2 — Analog input channel 2 (single-ended) |
| Pin 4 | AIN3 — Analog input channel 3 (single-ended) |
| Pin 5 | GND — Analog ground |
| Pin 6 | REF — Reference voltage input / internal reference bypass |
| Pin 7 | AVDD — Analog supply voltage (2.7V to 5.25V) |
| Pin 8 | AS — I2C address select (hardware pin) |
| Pin 9 | SDA — I2C serial data |
| Pin 10 | SCL — I2C serial clock |
| Pin 11 | DVDD — Digital supply voltage (derived from AVDD or external) |
| Pin 12 | DGND — Digital ground |
| Pin 13 | NC — Not connected (per datasheet) |
| Pin 14 | NC — Not connected (per datasheet) |
| Pin 15 | NC — Not connected (per datasheet) |
| Pin 16 | EP — Exposed thermal pad - connect to GND |
Typical Applications
AS1541-BQFT is suitable for 6 applications: Multi-Channel Sensor Monitoring, Portable / Battery-Powered Instrumentation, PLC Analog Input Modules, HVAC and Building Automation Controllers, Consumer Device User-Interface Controls, Data Acquisition Front-End for Embedded Systems.
Multi-Channel Sensor Monitoring
The AS1541-BQFT's integrated 4-channel analog multiplexer makes it a strong fit for monitoring up to 4 sensors from a single I2C-addressable ADC. With 10-bit resolution and 50 ksps sampling per channel, it cleanly digitizes temperature (via thermistor or RTD bridge output), pressure (bridge transducer), strain gauge, humidity, and process-voltage signals simultaneously. Placed near the sensor cluster with a shared AVDD rail and local 100 nF decoupling, it eliminates the need for an external analog switch and reduces BOM cost. Unlike sigma-delta ADCs, the SAR architecture provides single-conversion latency, ensuring deterministic readouts for alarm or threshold-detect applications.
Recommended
Portable / Battery-Powered Instrumentation
With 1.5 mA typical supply current at 50 ksps and software-controlled power-down mode that drops consumption to microampere levels, the AS1541-BQFT fits handheld multimeters, portable medical monitors, and field data loggers. The I2C interface minimizes pin count on small form-factor PCBs, and the 2.7V to 5.25V analog supply range accommodates single-cell Li-ion (3.0V to 4.2V) as well as 3.3V and 5V system rails directly. Engineers can duty-cycle conversions to extend battery life: wake, convert, transmit over I2C, then power down between samples.
Recommended
PLC Analog Input Modules
The AS1541-BQFT serves as a cost-effective multi-channel analog front end in Programmable Logic Controller (PLC) input modules, where 4 channels per IC and I2C addressing allow stacking up to 8 devices on a single bus (with the AS pin addressing two) for 32-channel modules. The 50 ksps sampling rate supports typical industrial process control loop update rates of 1 kHz or below. The 16-TQFN package is small enough for high-density DIN-rail module layouts, and the integrated 4:1 mux removes the need for an external analog switch IC, reducing BOM cost and PCB area.
Recommended
HVAC and Building Automation Controllers
Building automation systems digitize temperature, humidity, CO2, and airflow sensor signals across multiple zones, and the AS1541-BQFT is well-matched to this use case. Its 4-channel mux allows one ADC to monitor a small sensor cluster (e.g., supply air temperature, return air humidity, mixed-air CO2, and duct pressure) per zone. The I2C bus simplifies wiring back to a central microcontroller, and the 5.25V max supply supports 5V-powered sensor bridges directly. Compared with discrete op-amp + comparator designs, integrating the SAR ADC and mux simplifies firmware and reduces calibration points.
Recommended
Consumer Device User-Interface Controls
The AS1541-BQFT reads potentiometer positions, button-resistor ladders, and thermistor touch sensors in consumer appliances, audio equipment, and smart-home devices. The 4-channel input supports a small user-interface cluster (e.g., volume, bass, treble, balance potentiometers) on a single I2C address. The 10-bit resolution provides 1024 steps - more than sufficient for smooth user-interface feel. Low power consumption during idle is critical for always-on appliances, and the power-down mode keeps standby current in the microampere range.
Recommended
Data Acquisition Front-End for Embedded Systems
The AS1541-BQFT functions as a low-cost multi-channel data acquisition front-end for embedded microcontrollers (ARM Cortex-M, RISC-V, PIC) that lack integrated ADCs with sufficient channel count or resolution. The I2C interface is supported by virtually every modern MCU's hardware peripheral, requiring only two GPIO pins plus pull-ups. Combined with the on-chip track-and-hold and 4-channel mux, the AS1541-BQFT provides a complete 4-channel data acquisition subsystem in a single 4x4 mm TQFN footprint, simplifying PCB layout and BOM management in cost-sensitive embedded designs.
Recommended
Recommended Products Summary
Engineering reference data for AS1541-BQFT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AS1539-BQFT | ADS7822PBG4 | ADS7825PG4 | ADC121S021CISDX | ADS7824PG4 | ADS7828KPZ-REEL |
|---|---|---|---|---|---|---|---|
| Package | 16-TQFN (4x4 mm) with EP | 16-TQFN (4x4 mm) with EP - same | 16-TQFN (4x4 mm) - same | 16-TQFN (4x4 mm) - same | 16-TQFN (4x4 mm) - same | 16-TQFN (4x4 mm) - same | 16-TQFN (4x4 mm) - same |
| Brand | ams OSRAM | ams OSRAM (same-brand) | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Resolution | 10 bits | 10 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sampling Rate | 50 ksps | 50 ksps | 200 ksps | 200 ksps | 50-200 ksps | 200 ksps | 200 ksps |
| Input Channels | 4 single-ended | 8 single-ended | 8 single-ended | 8 single-ended | 1 single-ended | 4 single-ended | 8 single-ended |
| Interface | I2C (100/400 kHz) | I2C (100/400 kHz) | I2C | I2C/SPI | SPI | I2C | I2C |
| Supply Voltage | 2.7V to 5.25V | 2.7V to 5.25V | 2.7V to 5.25V | 2.7V to 5.25V | 2.7V to 5.25V | 2.7V to 5.25V | 2.7V to 5.25V |
| Source | this_product (target) | llm_knowledge (same-family) | web_data | web_data | web_data | web_data | web_data |
Key Differentiators
- Same-brand 8-channel upgrade path on identical package footprint (vs AS1539-BQFT)
- Pin-compatible 12-bit resolution upgrade from cross-brand TI (vs ADS7822PBG4)
- Wider channel-count coverage from cross-brand TI (vs ADS7828KPZ-REEL)
Design Notes
Decouple AVDD with a 100 nF ceramic capacitor placed within 5 mm of the AVDD pin, and add a bulk 1 uF to 10 uF tantalum or ceramic capacitor on the same rail for low-frequency noise suppression. DVDD typically derives from AVDD or from a separate digital regulator; if separate, decouple DVDD with 100 nF as well. Estimated: assuming a noisy 5V switching regulator upstream, the 100 nF cap reduces high-frequency noise by 20+ dB at the ADC input, which directly translates to better SNR at the conversion output.
Solder the exposed thermal pad (EP) to a grounded copper pour that spans at least 4x4 mm of copper area. This provides both thermal dissipation and a low-impedance analog ground return path. Keep analog and digital ground planes joined at a single point near the EP - do not run digital return currents through the analog ground plane beneath the ADC inputs, as this couples switching noise into the analog signal path.
Route the I2C SDA and SCL traces as short as possible, with pull-up resistors sized per the I2C specification (typically 2.2 kohm to 10 kohm depending on bus capacitance and speed). For Fast-Mode 400 kHz operation with multiple devices, calculate the pull-up value to ensure rise time meets the 300 ns specification. Place the pull-ups close to the AS1541-BQFT's SDA/SCL pins rather than at the bus master to minimize stub length and ringing.
Do not leave the REF pin floating - either rely on the internal 2.5V reference with proper bypass capacitor placement, or drive an external reference. Unused analog inputs should be tied to a known DC voltage (mid-rail or GND) to prevent the internal mux from sampling a floating node. When using the AS pin for I2C address selection, tie it directly to AVDD or GND - do not leave it floating, as the address decode logic depends on a stable logic level at startup.
Compliance Information
RoHS and lead-free compliance stated by ams OSRAM product page. AEC-Q100 not applicable - this is a commercial/industrial grade ADC. Halogen-free status not explicitly confirmed in available web data.
