Part A
ADS7809U
德州儀器
- Lifecycle
- Active
- Stock
- 6471 件
- Package
- SOIC-20
- Series
- 資料獲取-模數轉換器（ADC）
Replacement verdict
Compatible functional replacement candidate
The ADS7825UB/1K can serve as a functional replacement candidate for the ADS7809U in many designs, since both are 16-bit successive-approximation ADCs with comparable resolution and similar serial interface architecture. However, the ADS7825UB/1K offers a higher sampling rate and a different package and input configuration, so the replacement is not a drop-in substitute. Engineers should validate the package footprint, input range, and timing against the target design before committing to the substitution.
Resolution
High match
Interface Type
High match
Package Type
Validation required
Sampling Rate
Validation required
Parts at a glance
Part B
ADS7825UB/1K
德州儀器
- Lifecycle
- Active
- Stock
- 4144 件
- Package
- SOIC-28
- Series
- 資料獲取-模數轉換器（ADC）
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADS7809U | ADS7825UB/1K | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 16 bit | Both are 16-bit ADCs, so nominal resolution is equivalent for substitutability. |
| Number of Input Channels | 1 (single-ended) | 4 (single-ended, multiplexed) | The ADS7825 provides a 4-channel multiplexer, allowing multiple signals to be sampled by one device, whereas the ADS7809 is single-channel. |
| Sampling Rate | 100 kSPS | 40 kSPS | The ADS7809 supports a higher throughput, which matters for faster signal acquisition requirements. |
| Input Voltage Range | ±10 V | ±10 V | Both accept the same bipolar ±10 V input span, so signal conditioning can remain unchanged. |
| Interface Type | Serial (SPI/QSPI compatible) | Parallel | The digital interface differs fundamentally; the ADS7809 uses a serial bus while the ADS7825 uses a parallel bus, affecting board layout and host connection. |
| Supply Voltage | 5 V (analog and digital) | 5 V (analog and digital) | Both operate from a single 5 V supply, simplifying power supply design for either part. |
| Package | 28-pin SOIC | 28-pin SOIC | Identical package and pin count allow potential footprint compatibility, though pinout must be verified. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Both cover the industrial temperature range, so environmental suitability is equivalent. |
| Internal Reference | Yes (on-chip reference) | Yes (on-chip reference) | Both include an internal reference, reducing external component count and simplifying design. |
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 | ADS7809U | ADS7825UB/1K |
|---|---|---|
| Supplier | - | Texas Instruments,Rochester Electronics, LLC |
| Part Status | Active | Active |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 100k | 40k |
| Number of Inputs | 1 | 4 |
| Input Type | Single Ended | Single Ended |
| Data Interface | SPI, DSP | SPI, Parallel |
| Configuration | S/H-ADC | S/H-ADC |
| Ratio - S / H: ADC | 1:1 | 1:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | External, Internal | External, Internal |
| Voltage - Supply, Analog | 5V | 5V |
| Voltage - Supply, Digital | 5V | 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key architectural differences between the ADS7809U and the ADS7825UB/1K?
The ADS7809U is a 16-bit, 100 kSPS successive-approximation register (SAR) analog-to-digital converter with a parallel 16-bit output interface, while the ADS7825UB/1K is a 16-bit, 25 kSPS SAR ADC featuring a 4-channel input multiplexer and a serial SPI-compatible output interface. The ADS7809U provides a single-channel input with a full 16-bit parallel bus, whereas the ADS7825UB/1K integrates a 4-to-1 input multiplexer and communicates over a serial interface.
Can the ADS7809U and ADS7825UB/1K be used interchangeably in an existing design?
No, they are not pin-compatible or functionally interchangeable. The ADS7809U uses a 28-pin SOIC package with a parallel data bus, while the ADS7825UB/1K uses a 28-pin SOIC package with a serial interface and multiplexed inputs. The differing interface architectures, sampling rates, and input configurations require design changes to the host processor interface and analog front end before substitution.
How do the sampling rates of the ADS7809U and ADS7825UB/1K compare?
The ADS7809U offers a maximum throughput of 100 kSPS, whereas the ADS7825UB/1K provides a maximum throughput of 25 kSPS. The ADS7809U is therefore suited to higher-speed single-channel acquisition, while the ADS7825UB/1K is intended for multi-channel applications where 25 kSPS per channel is sufficient.
What input configurations do the ADS7809U and ADS7825UB/1K support?
The ADS7809U provides a single analog input channel with software-selectable input ranges of ±10 V, ±5 V, 0 to 10 V, and 0 to 5 V. The ADS7825UB/1K provides a 4-channel input multiplexer, allowing selection among four single-ended inputs, with a specified input range of 0 to 5 V. The ADS7809U is therefore better suited to single-channel bipolar or wide-range signals, while the ADS7825UB/1K suits multi-channel unipolar systems.
How do the digital interfaces of the ADS7809U and ADS7825UB/1K differ?
The ADS7809U provides a 16-bit parallel output interface with standard microprocessor control signals (CS, R/C, BYTE, and BUSY), enabling direct connection to a parallel bus. The ADS7825UB/1K provides a serial SPI-compatible interface with a 16-bit serial data output, allowing connection to microcontrollers and DSPs with fewer I/O pins. The interface choice directly affects PCB routing, pin count, and host firmware.
Do the ADS7809U and ADS7825UB/1K have the same package and pinout?
Both devices are offered in a 28-pin SOIC package, but their pinouts and functions differ because of the different interface and input architectures. The ADS7809U assigns pins to a parallel data bus and single-channel analog input, while the ADS7825UB/1K assigns pins to serial data, multiplexer channel selection, and four analog inputs. They are not drop-in replacements for each other.
What are the typical power supply requirements for the ADS7809U and ADS7825UB/1K?
The ADS7809U operates from a single +5 V analog supply and a +5 V digital supply, with an internal reference and specified power dissipation suitable for its 100 kSPS operation. The ADS7825UB/1K operates from a single +5 V supply and includes an internal reference, with power consumption specified for its 25 kSPS throughput. Both are 5 V single-supply SAR converters, but the ADS7809U's higher throughput results in higher dynamic power consumption.
Which device is better suited for multi-channel data acquisition systems?
The ADS7825UB/1K is better suited for multi-channel data acquisition because it integrates a 4-channel input multiplexer, allowing four single-ended signals to be digitized through one converter with serial output. The ADS7809U has only a single analog input channel, so multi-channel systems would require external multiplexing and additional board space. However, the ADS7809U's 100 kSPS rate may be preferable when higher per-channel throughput is required.