Part A
ADUC831BSZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2439 PCS
- Package
- MQFP-52
- Series
- Embedded - Microcontrollers
Replacement verdict
Compatible functional replacement candidate
The ADUC831BSZ and ADUC845BS8-3 are both MicroConverter 12-bit ADC MCUs from the same Analog Devices family, sharing core architecture and on-chip peripherals, but they differ in package, supply voltage, and memory configuration. The ADUC845BS8-3 is a viable functional candidate only after validating package footprint, supply rail, and flash/RAM requirements against the target design.
Package Type
Validation required
Supply Voltage
Validation required
Core Architecture
High match
Memory Configuration
Validation required
Parts at a glance
Part B
ADUC845BS8-3
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 181 PCS
- Package
- QFP-52
- Series
- Embedded - Microcontrollers
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADUC831BSZ | ADUC845BS8-3 | Why it matters |
|---|---|---|---|
| Core / CPU | 8051-compatible (single-cycle, 16 MHz max) | 8051-compatible (single-cycle, 12.58 MHz max) | Both are 8051 cores, but the maximum core clock differs, affecting instruction throughput and timing of peripherals. |
| Program Memory (Flash) | 62 kB | 62 kB | Flash size determines how much application code can be stored on-chip; identical here, so code size is not a differentiator. |
| Data Memory (SRAM) | 2 kB | 2.25 kB | On-chip SRAM affects available working memory for variables and stack; the slight difference may matter for memory-constrained firmware. |
| ADC Resolution / Channels | 12-bit, 8-channel (self-calibrating) | 24-bit, 8-channel (sigma-delta) | ADC architecture and resolution fundamentally determine measurement precision and are a primary reason to choose one part over the other. |
| DAC | Dual 12-bit voltage-output DAC | Dual 16-bit voltage-output DAC | DAC resolution affects analog output fidelity; the higher-resolution DAC on the ADUC845BS8-3 enables finer control in closed-loop applications. |
| Supply Voltage | 3.0 V to 3.6 V | 3.0 V to 3.6 V | Operating supply range must match the system rail; identical here, so power-supply design is compatible between the two. |
| Package | 48-lead LQFP | 52-lead MQFP | Package footprint and pin count affect PCB layout and cannot be swapped without a board redesign. |
| UART / Serial Interfaces | UART, SPI, I2C | UART, SPI, I2C | Serial interface availability determines connectivity options; identical here, so communication peripherals are interchangeable. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range defines environmental suitability; identical here, so both suit the same industrial-grade environments. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADUC831BSZ | ADUC845BS8-3 |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | MicroConverter® ADuC8xx | MicroConverter® ADuC8xx |
| Part Status | Active | Obsolete |
| Core Processor | 8052 | 8052 |
| Core Size | 8-Bit | 8-Bit |
| Speed | 16MHz | 12.58MHz |
| Connectivity | EBI/EMI, I²C, SPI, UART/USART | I²C, SPI, UART/USART |
| Peripherals | PSM, Temp Sensor, WDT | POR, PSM, PWM, Temp Sensor, WDT |
| Number of I/O | 34 | 34 |
| Program Memory Size | 62KB (62K x 8) | 8KB (8K x 8) |
| Program Memory Type | FLASH | FLASH |
| EEPROM Size | 4K x 8 | 4K x 8 |
| RAM Size | 2.25K x 8 | 2.25K x 8 |
| Voltage - Supply (Vcc/Vdd) | 2.7V ~ 5.5V | 2.7V ~ 3.6V |
| Data Converters | A/D 8x12b; D/A 2x12b | A/D 10x24b; D/A 1x12b, 2x16b |
| Oscillator Type | Internal | Internal |
| Operating Temperature | -40°C ~ 125°C (TA) | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the core differences between the ADUC831BSZ and the ADUC845BS8-3?
The ADUC831BSZ is a MicroConverter 12-bit ADC with embedded 8-bit MCU in a 52-lead MQFP package, while the ADUC845BS8-3 is a MicroConverter dual 24-bit/16-bit sigma-delta ADC with embedded 8-bit MCU in an 80-lead LQFP package. The ADUC845BS8-3 offers higher resolution sigma-delta ADCs and more on-chip memory, whereas the ADUC831BSZ provides a faster 12-bit SAR ADC architecture.
Are the ADUC831BSZ and ADUC845BS8-3 pin-to-pin compatible?
No. The ADUC831BSZ uses a 52-lead MQFP package and the ADUC845BS8-3 uses an 80-lead LQFP package. The pin counts, package dimensions, and pin functions differ, so they are not drop-in replacements and require different PCB footprints.
What are the ADC architectures and resolutions of each device?
The ADUC831BSZ integrates a 12-bit successive-approximation (SAR) ADC with up to 8 input channels. The ADUC845BS8-3 integrates dual sigma-delta ADCs: one 24-bit primary ADC and one 16-bit auxiliary ADC, suited for high-resolution low-frequency measurement applications.
How do the on-chip memory specifications compare?
The ADUC831BSZ provides 62 kBytes of on-chip flash/EE program memory and 2 kBytes of on-chip data RAM. The ADUC845BS8-3 provides 62 kBytes of on-chip flash/EE program memory and 2.25 kBytes of on-chip data RAM. Both include on-chip flash/EE data memory, but designers should confirm exact memory maps in the respective datasheets.
What are the supply voltage and operating temperature ranges for these parts?
The ADUC831BSZ operates from a 3 V to 3.6 V supply. The ADUC845BS8-3 is specified for 3 V operation (the "-3" suffix denotes the 3 V version). Both are specified over the industrial temperature range of -40°C to +85°C. Verify exact limits in the manufacturer datasheets.
Which device is better suited for high-resolution sensor measurement?
The ADUC845BS8-3 is generally better suited for high-resolution sensor measurement because its 24-bit sigma-delta primary ADC provides significantly higher resolution and lower noise for low-frequency signals. The ADUC831BSZ's 12-bit SAR ADC is better suited for faster, lower-resolution multi-channel sampling.
Do both devices include on-chip UART, SPI, and I2C serial interfaces?
Both the ADUC831BSZ and ADUC845BS8-3 integrate a UART, an SPI interface, and an I2C-compatible interface as part of the MicroConverter serial peripheral set. Designers should confirm the exact peripheral configuration and pin multiplexing in the respective datasheets.
Can the ADUC831BSZ be used as a substitute for the ADUC845BS8-3 in an existing design?
No, not as a direct substitute. The devices differ in package, pinout, ADC architecture, resolution, and memory. Substitution would require PCB redesign, firmware changes, and revalidation against the target application requirements.