Part A
ADS8568SPMR
Texas Instruments
- Lifecycle
- Active
- Stock
- 7064 PCS
- Package
- LQFP-64
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADS8556IPMR and ADS8568SPMR are both 16-bit, 6-channel, simultaneous-sampling SAR ADCs from Texas Instruments with matching resolution, channel count, and parallel interface architecture, making them strong functional replacement candidates. However, the ADS8568SPMR offers a faster 510 kSPS throughput versus 450 kSPS on the ADS8556IPMR, and the two devices differ in package and temperature grade, so the replacement should be validated against the target application's timing margin and thermal requirements before adoption.
Resolution and Channel Count
High match
Sample Rate
Validation required
Package Type
Validation required
Operating Temperature Range
Validation required
Parts at a glance
Part B
ADS8556IPMR
Texas Instruments
- Lifecycle
- Active
- Stock
- 2848 PCS
- Package
- LQFP-64
- 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 | ADS8556IPMR | ADS8568SPMR | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 16 bit | Both are 16-bit SAR ADCs, so nominal resolution is equivalent for substitutability. |
| Number of Input Channels | 6 single-ended / 3 differential | 8 single-ended / 4 differential | Channel count determines how many signals can be sampled; the ADS8568 offers two additional channels, which may be required by the application. |
| Sampling Rate (max) | 630 kSPS | 500 kSPS | Maximum throughput affects the highest signal bandwidth that can be captured; the ADS8556 supports a higher sample rate. |
| Supply Voltage (Analog) | 5 V (4.5 V to 5.5 V) | 5 V (4.5 V to 5.5 V) | Analog supply range must match the system's analog front-end rails for correct full-scale operation. |
| Digital Interface Supply | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Flexible digital I/O supply allows direct interfacing to 3.3 V or 5 V logic without level shifters. |
| Interface Type | Parallel / Serial (SPI) | Parallel / Serial (SPI) | Both support parallel and serial readout, so the host controller interface can remain unchanged. |
| Package | LQFP-64 | LQFP-64 | Identical package and pin count simplify PCB layout reuse and drop-in substitution. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Industrial temperature range ensures reliable operation in harsh environments for both parts. |
| Input Type | Single-ended / Pseudo-differential | Single-ended / Pseudo-differential | Matching input configurations allow the same sensor front-end topology to be used with either device. |
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 | ADS8568SPMR | ADS8556IPMR |
|---|---|---|
| Part Status | Active | Active |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 500k | 630k |
| Number of Inputs | 8 | 6 |
| Input Type | Single Ended | Single Ended |
| Data Interface | SPI, Parallel | 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 | 2.7V ~ 5.5V | 2.7V ~ 3.6V, 5V |
| Features | Simultaneous Sampling | Simultaneous Sampling |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 125°C |
Frequently asked questions
What are the key differences between the ADS8556IPMR and ADS8568SPMR?
The ADS8556IPMR is a 16-bit, 6-channel simultaneous-sampling SAR ADC, while the ADS8568SPMR is a 16-bit, 8-channel simultaneous-sampling SAR ADC. Both are pin-compatible members of the ADS85x6 family, but the ADS8568 provides two additional analog input channels. The ADS8556IPMR is specified over the industrial temperature range of -40°C to +125°C, whereas the ADS8568SPMR is specified over the -40°C to +125°C range as well; however, the "I" and "S" suffixes denote different qualification/grade designations per the respective datasheets.
Are the ADS8556IPMR and ADS8568SPMR pin-compatible?
Yes. Both devices are offered in the same 64-pin LQFP (PM) package and belong to the same ADS85x6 family, sharing a common pinout. This allows a single PCB layout to accommodate either device, with the additional channels of the ADS8568SPMR routed as needed.
What is the maximum sampling rate of these ADCs?
Both the ADS8556IPMR and ADS8568SPMR support a maximum throughput of 630 kSPS per channel in parallel interface mode. In serial interface mode, the maximum throughput is 500 kSPS per channel, per the respective manufacturer datasheets.
What analog input voltage range do these devices support?
Both devices support bipolar analog input ranges of ±10 V, ±5 V, and ±2.5 V, as well as a 0 V to 5 V unipolar range, selectable via configuration. This makes them suitable for industrial signal acquisition where wide dynamic range is required.
What digital interfaces are available on the ADS8556IPMR and ADS8568SPMR?
Both devices provide a flexible parallel interface (16-bit or 8-bit) and a serial interface (SPI-compatible) for connection to host processors or FPGAs. The interface mode is selectable, allowing the same device to be used in either high-speed parallel or pin-efficient serial system architectures.
Do these ADCs include an internal voltage reference?
Yes. Both the ADS8556IPMR and ADS8568SPMR integrate an internal voltage reference, which reduces external component count. An external reference can also be supplied if the application requires a different reference voltage or improved drift performance.
What is the typical power consumption of these devices?
Both devices operate from a 5 V analog supply and a 2.7 V to 5.5 V digital supply. Typical power consumption is approximately 250 mW at the full 630 kSPS throughput in parallel mode, per the manufacturer datasheet. Power scales down with lower throughput and can be further reduced using the device's power-down modes.
Can the ADS8556IPMR be replaced by the ADS8568SPMR in an existing design?
Because the two devices are pin-compatible and share the same package and interface options, the ADS8568SPMR can generally be used in place of the ADS8556IPMR when the two additional input channels are either used or left unconnected. However, the designer must verify that the "S" grade specifications (temperature range, accuracy grades, and qualification level) meet the target application requirements before substitution.