Part A
ADS8691IPW
Texas Dụng cụ
- Lifecycle
- Active
- Stock
- 7455 PCS
- Package
- TSSOP-16
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADS8691IPW is a viable functional replacement candidate for the ADS8681IPWR, sharing the same 16-bit SAR architecture, single-ended input configuration, and TSSOP-16 footprint, though the higher sampling rate and wider input range of the ADS8691IPW require validation against the target application's timing and signal-conditioning requirements.
Resolution and Architecture
High match
Package and Pinout
High match
Sampling Rate
Validation required
Input Voltage Range
Validation required
Parts at a glance
Part B
ADS8681IPWR
Texas Dụng cụ
- Lifecycle
- Active
- Stock
- 7571 PCS
- Package
- TSSOP-16
- Series
- Data Acquisition - Analog to Digital Converters (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 | ADS8681IPWR | ADS8691IPW | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 18 bit | Higher resolution provides finer measurement granularity and lower quantization error, which directly affects achievable accuracy in precision data acquisition. |
| Number of Input Channels | 1 single-ended | 1 single-ended | Channel count determines how many signals can be digitized; both are single-channel devices, so system architecture for multi-signal sensing must account for this. |
| Sampling Rate (Max) | 1 MSPS | 500 kSPS | Maximum throughput limits the bandwidth of signals that can be captured and affects anti-aliasing filter design and overall system response time. |
| Input Voltage Range | ±10.24 V (bipolar, programmable) | ±10.24 V (bipolar, programmable) | Programmable input ranges allow direct connection to various sensors and industrial signal levels without external conditioning, simplifying the analog front end. |
| INL (Integral Nonlinearity) | ±1 LSB (typ) | ±2 LSB (typ) | INL characterizes deviation from an ideal transfer function and is a key indicator of absolute accuracy in precision measurement applications. |
| SNR (Signal-to-Noise Ratio) | 92 dB (typ) | 101 dB (typ) | SNR defines the noise floor relative to full-scale input; higher SNR enables detection of smaller signals and improves effective resolution. |
| Supply Voltage | 5 V analog, 1.65–5 V digital | 5 V analog, 1.65–5 V digital | Supply requirements determine compatibility with the host logic and power rails, affecting level shifting and power supply design. |
| Interface | SPI (serial) | SPI (serial) | The digital interface must match the host controller; SPI compatibility ensures drop-in communication with existing microcontrollers or FPGAs. |
| Package | 16-pin TSSOP (PW) | 16-pin TSSOP (PW) | Package and pinout determine PCB footprint compatibility; identical packages allow the same board layout to accommodate either part. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Industrial temperature range ensures reliable operation in harsh environments and validates suitability for industrial and automotive applications. |
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 | ADS8691IPW | ADS8681IPWR |
|---|---|---|
| Series | ADS869x | - |
| Part Status | Active | Active |
| Number of Bits | 18 | 16 |
| Sampling Rate(Per Second) | 1M | 1M |
| Number of Inputs | 1 | 1 |
| Input Type | Differential, Pseudo-Differential, Single Ended | Pseudo-Differential, Single Ended |
| Data Interface | SPI | SPI |
| Configuration | PGA-ADC | PGA-S/H-ADC |
| Ratio - S / H: ADC | 0:1 | 1:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | Internal | External, Internal |
| Voltage - Supply, Analog | 4.75V ~ 5.25V | 5V |
| Voltage - Supply, Digital | 1.65V ~ 3.3V | 1.65V ~ 5.25V |
| Features | Internal Oscillator | PGA |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 125°C (TA) |
Frequently asked questions
What are the key differences between the ADS8681IPWR and ADS8691IPW?
Both are 16-bit, single-channel, successive-approximation register (SAR) analog-to-digital converters (ADCs) from Texas Instruments with integrated analog front-end. The ADS8681IPWR is specified for a 5-V analog supply with a ±10.24 V input range and is offered in a TSSOP-16 (PW) package in tape-and-reel form. The ADS8691IPW is specified for a 5-V analog supply with a ±10.24 V input range and is offered in a TSSOP-16 (PW) package in tube form. The primary differences are ordering/package quantity conventions and the specific input range and supply configuration documented in each respective datasheet.
Are the ADS8681IPWR and ADS8691IPW pin-compatible?
Both devices are offered in the same TSSOP-16 (PW) package, and their pin functions follow the same family pinout defined in the respective Texas Instruments datasheets. Designers should confirm pin assignments against the specific datasheet revision before layout, since pin function definitions must be verified per device documentation.
What is the resolution and architecture of these ADCs?
Both the ADS8681IPWR and ADS8691IPW are 16-bit SAR ADCs with integrated analog front-end circuitry, including an input overvoltage protection network and programmable gain, as documented in the Texas Instruments datasheets.
What input voltage range do these devices support?
The ADS8681IPWR supports a bipolar input range of ±10.24 V with a 5-V analog supply, per the Texas Instruments datasheet. The ADS8691IPW likewise supports a ±10.24 V bipolar input range with a 5-V analog supply, per its datasheet. Both devices provide programmable input ranges within the family specification; consult the respective datasheet for the complete range table.
What digital interface do the ADS8681IPWR and ADS8691IPW use?
Both devices provide an SPI-compatible serial interface for configuration and data readback, as specified in the Texas Instruments datasheets. The interface supports daisy-chain and multi-device configurations per the documented timing and register map.
What are the package and ordering differences between the two part numbers?
The ADS8681IPWR uses the PW (TSSOP-16) package with the R suffix indicating tape-and-reel packaging. The ADS8691IPW uses the PW (TSSOP-16) package without the R suffix, indicating tube packaging. Both are specified over the industrial temperature range per the Texas Instruments datasheets.
Can the ADS8681IPWR and ADS8691IPW be used interchangeably in an existing design?
Because both are 16-bit SAR ADCs in the same TSSOP-16 package with SPI interfaces and ±10.24 V input ranges, they are candidates for substitution, but interchangeability must be validated against the specific datasheet parameters, register maps, timing specifications, and the target design requirements before use. Do not substitute without verifying all electrical and functional differences against manufacturer documentation.