Part A
ADS8691IPW
Texas Instruments
- Lifecycle
- Active
- Stock
- 7455 PCS
- Package
- TSSOP-16
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADS8665IPWR and ADS8691IPW share the same TSSOP-16 footprint and 5 V analog supply, but differ in resolution, input range, and throughput, so the ADS8691IPW can serve as a functional upgrade only after validating sampling rate, input scaling, and digital timing against the target design.
Resolution
Validation required
Input Voltage Range
Validation required
Sampling Rate
Validation required
Package Type
High match
Parts at a glance
Part B
ADS8665IPWR
Texas Instruments
- Lifecycle
- Active
- Stock
- 6457 PCS
- Package
- TSSOP-16
- Series
- Acquisition de données - Convertisseur analogique - numérique (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 | ADS8665IPWR | ADS8691IPW | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 18 bit | Higher resolution provides finer measurement granularity and lower quantization error, which is critical for precision sensing applications. |
| 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 multiplexing needs are identical. |
| Sampling Rate (max) | 500 kSPS | 1 MSPS | Maximum throughput affects the ability to capture fast-changing signals and the achievable bandwidth of the measurement system. |
| Input Voltage Range | ±10.24 V (bipolar, programmable) | ±10.24 V (bipolar, programmable) | The input range must match the sensor or signal amplitude to avoid clipping and to maximize dynamic range utilization. |
| Interface Type | SPI (serial) | SPI (serial) | The digital interface must be compatible with the host controller; both use SPI, simplifying drop-in replacement at the protocol level. |
| Supply Voltage | 5 V analog, 1.65–5.5 V digital | 5 V analog, 1.65–5.5 V digital | Supply requirements determine power rail design and compatibility with existing board-level power architecture. |
| INL (Integral Nonlinearity) | ±0.5 LSB (typ) | ±1.5 LSB (typ) | INL indicates deviation from an ideal transfer function and directly impacts absolute accuracy of the conversion. |
| Package | TSSOP-16 | TSSOP-16 | Package footprint and pinout must match for physical board compatibility in a substitution scenario. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | The temperature range must cover the application environment to ensure reliable operation and specified performance. |
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 | ADS8665IPWR |
|---|---|---|
| Series | ADS869x | - |
| Part Status | Active | Active |
| Number of Bits | 18 | 12 |
| Sampling Rate(Per Second) | 1M | 500k |
| Number of Inputs | 1 | 1 |
| Input Type | Differential, Pseudo-Differential, Single Ended | Differential, Pseudo-Differential, Single Ended |
| Data Interface | SPI | SPI |
| Configuration | PGA-ADC | PGA-ADC |
| Ratio - S / H: ADC | 0:1 | 0:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | Internal | Internal |
| Voltage - Supply, Analog | 4.75V ~ 5.25V | 4.75V ~ 5.25V |
| Voltage - Supply, Digital | 1.65V ~ 3.3V | 1.65V ~ 5.25V |
| Features | Internal Oscillator | Internal Oscillator, PGA |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 125°C |
Frequently asked questions
What are the key differences between the ADS8665IPWR and ADS8691IPW?
The ADS8665IPWR is a single-channel, 12-bit SAR ADC with a 500 kSPS maximum throughput in a TSSOP-16 package, while the ADS8691IPW is a single-channel, 18-bit SAR ADC with a 1 MSPS maximum throughput in a TSSOP-16 package. The ADS8691IPW offers higher resolution and faster sampling, whereas the ADS8665IPWR targets lower-resolution, lower-speed applications.
Do the ADS8665IPWR and ADS8691IPW share the same package and pinout?
Both devices are offered in a 16-pin TSSOP (PW) package, but they are not pin-to-pin compatible. The ADS8665IPWR and ADS8691IPW have different pin functions and internal architectures, so PCB layouts and pin assignments must be verified against each respective datasheet before substitution.
What are the resolution and sampling rate specifications for each device?
The ADS8665IPWR provides 12-bit resolution with a maximum throughput of 500 kSPS. The ADS8691IPW provides 18-bit resolution with a maximum throughput of 1 MSPS. These differences directly affect achievable dynamic range and signal bandwidth in the target application.
What input voltage range does each ADC support?
The ADS8665IPWR supports a bipolar input range of ±10.24 V with a 4.096 V internal reference. The ADS8691IPW supports a bipolar input range of ±10.24 V as well, with an integrated reference. Both devices are designed for high-voltage bipolar signal acquisition, but the ADS8691IPW provides higher resolution for the same input span.
What digital interfaces do the ADS8665IPWR and ADS8691IPW use?
Both devices use an SPI-compatible serial interface for communication with a host controller. The interface supports daisy-chain operation and is compatible with standard SPI modes, allowing direct connection to microcontrollers and FPGAs without additional glue logic.
Can the ADS8665IPWR be used as a drop-in replacement for the ADS8691IPW?
No. Although both are single-channel SAR ADCs in 16-pin TSSOP packages, they differ in resolution (12-bit vs 18-bit), maximum throughput (500 kSPS vs 1 MSPS), and pin functions. A direct drop-in replacement is not supported; the design must be revalidated against the target device datasheet.
What are the typical applications for each device?
The ADS8665IPWR is suited for medium-resolution, medium-speed data acquisition such as industrial process control and power monitoring. The ADS8691IPW targets higher-precision applications requiring 18-bit resolution and 1 MSPS throughput, such as advanced industrial instrumentation and high-accuracy signal measurement systems.