Part A
ADS8568SPM
Texas Instruments
- Lifecycle
- Active
- Stock
- 3952 PCS
- Package
- LQFP-64
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADS8556IPM and ADS8568SPM are both 16-bit, 6-channel, simultaneous-sampling SAR ADCs from Texas Instruments with matching resolution, channel count, and parallel interface architecture, making the ADS8568SPM a viable functional replacement candidate for the ADS8556IPM. Designers should validate the differing input voltage range and package footprint against their specific application requirements before substitution.
Resolution
High match
Channel Count
High match
Input Voltage Range
Validation required
Package Type
Validation required
Parts at a glance
Part B
ADS8556IPM
Texas Instruments
- Lifecycle
- Active
- Stock
- 6944 PCS
- Package
- LQFP-64
- 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 | ADS8556IPM | ADS8568SPM | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 16 bit | Both are 16-bit SAR ADCs, so nominal resolution is identical and does not differentiate 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 single-ended channels, affecting system architecture. |
| Maximum Sampling Rate | 630 kSPS | 510 kSPS | Sampling rate limits the maximum signal bandwidth and throughput; the ADS8556 is faster, which matters for high-speed acquisition. |
| Input Voltage Range | ±10 V (bipolar, configurable) | ±10 V (bipolar, configurable) | Both support wide bipolar input ranges, allowing direct connection to industrial-level signals without external conditioning. |
| Supply Voltage | 5 V analog (AVDD), 2.7–5.5 V digital (DVDD) | 5 V analog (AVDD), 2.7–5.5 V digital (DVDD) | Supply requirements are identical, so power supply design can be reused between the two parts. |
| Interface Type | Parallel / Serial (SPI-compatible) | Parallel / Serial (SPI-compatible) | Both offer flexible parallel and serial interfaces, easing drop-in compatibility with existing digital hosts. |
| Package | 64-pin LQFP (PM) | 64-pin LQFP (PM) | Identical package and pin count simplify PCB layout reuse and mechanical compatibility. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Matching industrial temperature ranges ensure both parts suit the same harsh-environment applications. |
| Power Consumption (typical) | ~250 mW | ~300 mW | Power dissipation affects thermal design and energy budget; the ADS8568 draws slightly more due to extra channels. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS8568SPM | ADS8556IPM |
|---|---|---|
| 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 ADS8556IPM and ADS8568SPM?
The ADS8556IPM is a 6-channel, 16-bit simultaneous-sampling SAR ADC, while the ADS8568SPM is an 8-channel, 16-bit simultaneous-sampling SAR ADC. Both are pin-compatible members of the ADS85x6 family, but the ADS8568SPM provides two additional analog input channels. The ADS8556IPM is specified over the industrial temperature range (−40°C to +125°C), whereas the ADS8568SPM is specified over the automotive/industrial temperature range (−40°C to +125°C) with automotive qualification per the datasheet.
Are the ADS8556IPM and ADS8568SPM pin-compatible and can they be swapped on the same PCB?
Yes. Both devices are offered in the same 64-pin LQFP (PM) package with identical pinouts, so they are footprint-compatible. However, a direct swap requires verifying that the additional channels of the ADS8568SPM are either used or properly terminated, and that the firmware/configuration for channel count is updated accordingly.
What is the maximum sampling rate of the ADS8556IPM and ADS8568SPM?
Both devices support a maximum throughput of 500 kSPS per channel in parallel interface mode. In serial interface mode, the maximum aggregate throughput is limited by the serial clock rate; refer to the respective datasheets for the exact serial timing limits.
Do the ADS8556IPM and ADS8568SPM support both parallel and serial interfaces?
Yes. Both ADCs provide a flexible parallel interface (16-bit or 8-bit) and a serial interface (SPI-compatible), selectable via the PAR/SER control pin. This allows the same device to be used with different host controllers without changing the analog front end.
What is the analog input voltage range of the ADS8556IPM and ADS8568SPM?
Both devices support bipolar analog input ranges of ±10 V, ±5 V, and ±2.5 V, as well as a unipolar 0 V to 5 V range, configured via the range-select pins. The input structure is a true differential sample-and-hold with high input impedance, allowing direct connection to industrial sensors and PLC front ends.
What are the power supply requirements for the ADS8556IPM and ADS8568SPM?
Both devices require an analog supply (AVDD) of 5 V and a digital supply (DVDD) of 2.7 V to 5.5 V. An additional negative supply (HVSS) of −15 V is required for the bipolar input ranges. Power consumption is typically around 250 mW per device at 500 kSPS with all channels active, depending on the interface mode and supply configuration.
What are the typical applications for the ADS8556IPM and ADS8568SPM?
These ADCs are intended for industrial automation, motor control, power quality measurement, protective relays, and multi-axis data acquisition systems. The 6-channel ADS8556IPM suits three-phase plus auxiliary monitoring, while the 8-channel ADS8568SPM suits higher-channel-count simultaneous-sampling applications such as multi-phase power monitoring and industrial PLC analog input modules.
What is the difference in package and temperature grade between the ADS8556IPM and ADS8568SPM?
Both are supplied in the 64-pin LQFP package. The ADS8556IPM is rated for the industrial temperature range of −40°C to +125°C. The ADS8568SPM is also rated for −40°C to +125°C and is qualified for automotive applications per the manufacturer's datasheet. Designers should confirm the specific qualification level required for their end application.