1 Features
1• Family of 16-, 14-, 12-Bit, Pin- and
Software-Compatible ADCs
• Six SAR ADCs Grouped in Three Pairs
• Maximum Data Rate Per Channel with Internal
Conversion Clock and Reference:
ADS8556: 630 kSPS (PAR) or 450 kSPS (SER)
ADS8557: 670 kSPS (PAR) or 470 kSPS (SER)
ADS8558: 730 kSPS (PAR) or 500 kSPS (SER)
• Maximum Data Rate with External Conversion
Clock and Reference:
800 kSPS (PAR) or 530 kSPS (SER)
• Pin-Selectable or Programmable Input Voltage
Ranges: Up to ±12 V
• Excellent Signal-to-Noise Performance:
ADS8556: 91.5 dB, ADS8667: 85 dB,
ADS8668: 73.9 dB
• Programmable and Buffered Internal Reference:
0.5 V to 2.5 V and 0.5 V to 3.0 V
• Comprehensive Power-Down Modes:
– Deep Power-Down (Standby Mode)
– Partial Power-Down
– Auto-Nap Power-Down
• Selectable Parallel or Serial Interface
• Operating Temperature Range: –40°C to 125°C

2 Applications
• Power Quality Measurement
• Protection Relays
• Multi-Axis Motor Control
• Programmable Logic Controllers
• Industrial Data Acquisition

3 Description
The ADS855x contains six low-power, 16-, 14-, or 12-
bit, successive approximation register (SAR) based
analog-to-digital converters (ADCs) with true bipolar
inputs. Each channel contains a sample-and-hold
circuit that allows simultaneous high-speed multichannel
signal acquisition.
The ADS855x supports data rates of up to 730 kSPS
in parallel interface mode or up to 500 kSPS if the
serial interface is used. The bus width of the parallel
interface can be set to eight or 16 bits. In serial
mode, up to three output channels can be activated.
The ADS855x is specified over the full industrial
temperature range of –40°C to 125°C and is available
in an LQFP-64 package.