To address applications demanding higher-speed and higher-resolution analog-to-digital conversion, Microchip Technology Inc. announced 12 new Successive Approximation Register (SAR) Analog-to-Digital Converters (ADCs) along with a companion differential amplifier that the company designed specifically for its new portfolio of SAR ADCs.
Suitable for applications such as high-precision data acquisition, electric vehicle battery management, motor control and switch-mode power supplies, the AEC-Q100-qualified family provides reliable performance across harsh environments. Additional applications include medical instruments, test equipment (See image above), and battery powered equipment.
The MCP331x1(D)-xx family was designed to operate in high temperatures and high electromagnetic environments. The family includes what the company claims to be the only one million samples per second (Msps) fully AEC-Q100-qualified 16-bit SAR, providing the reliability required for automotive and industrial applications. The MCP6D11 differential amplifier offers a low-distortion, high-accuracy interface to achieve the full performance of the ADC within systems.
The MCP331x1(D)-xx family ranges in resolution from 12-, 14-, and 16-bit with speed options ranging from 500 kilosamples per second (ksps) to 1-Million samples per second (Msps). This variety of resolution options and speeds help ensure that developers can pick the right ADC for their designs.
A fixed low analog supply voltage (AVdd) of 1.8V and low-current operation (1.6mA typical active current for 1 Msps and 1.4mA for 500 ksps) enables this family of ADCs to have an ultra-low power consumption while maintaining a wide input full-scale range.
These devices support a wide digital I/O interface voltage (DVIO) range (1.7V to 5.5V) which allows it to interface with most host devices, including Microchip’s PIC32, AVR® and Arm®-based microcontrollers and microprocessors. This ability to interface with most host devices eliminates the need for using external voltage level shifters.
The MCP331x1(D)-xx family contains both single-ended and differential-input voltage measurement options, enabling systems to convert the difference between any two arbitrary waveforms.
Properly interfacing a small analog signal to a high-speed, high-resolution ADC without introducing additional noise and distortion is a critical challenge. Microchip’s MCP6D11 differential amplifier is designed specifically to address this challenge, providing a low-distortion and high-accuracy interface to properly drive the ADC.
“The ADC market and applications are pushing toward higher resolution, higher speed and higher accuracy,” said Bryan J. Liddiard, vice president of Microchip’s mixed-signal and linear business unit. “In addition, lower power consumption and smaller packaging are also tremendously important, and these products address all these demands.”
Power-up and Standby Mode
When the device is first powered-up, it performs a self-calibration to minimize offset, gain and linearity errors. The device performance stays stable across the specified temperature range. However, when extreme changes in the operating environment, such as in the reference voltage, are made with respect to the initial conditions (e.g. the reference voltage was not fully settled during the initial power-up sequence), the user may send a recalibrate command anytime to initiate another self-calibration to restore optimum performance.
When the initial power-up sequence is completed, the device enters a low-current input acquisition mode, where sampling capacitors are connected to the input pins. This mode is called Standby. During Standby, most of the internal analog circuitry is shutdown in order to reduce current consumption. Typically, the device consumes less than 1 µA during Standby.
A new conversion is started on the rising edge of CNVST. When the conversion is complete and the host lowers CNVST, the output data is presented on SDO, and the device enters Standby to begin acquiring the next input sample. The user can clock out the ADC output data using the SPI-compatible serial clock during Standby. The ADC system clock is generated by an internal on-chip clock, therefore the conversion is performed independently of the SPI serial clock (SCLK).
- Sample Rate (Throughput):
- MCP33131/21/11-10: 1Msps
- MCP33131/21/11-05: 500kSPS
- 16/14/12-Bit Resolution with No Missing Codes
- No Latency Output
- Wide Operating Voltage Range:
- Analog Supply Voltage (AVdd): 1.8V
- Digital Input/Output Interface Voltage (DVIO): 1.7V to 5.5V
- External Reference (VREF): 2.5V to 5.1V
- Pseudo-Differential Input Operation with Single-Ended Configuration:
- Input Full-Scale Range: 0V to +Vref
- Ultra Low Current Consumption (typical):
- During Input Acquisition (Standby): ~ 0.8µA
- During Conversion:
- MCP331x1-10: ~1.6mA
- MCP331x1-05: ~1.4mA
- SPI-Compatible Serial Communication:
- SCLK Clock Rate: up to 100MHz
- ADC Self-Calibration for Offset, Gain, and Linearity Errors:
- During Power-Up (automatic)
- On-Demand via user’s command during normal operation
- AEC-Q100 Qualified:
- Temperature Grade 1: -40°C to +125°C
- Package Options: MSOP-10 and TDFN-10
The MCP331x1D-XX Evaluation Kit is available to demonstrate the performance of the MCP331x1D-XX SAR ADC family devices.
The evaluation kit includes the following:
- MCP331x1D Evaluation Board
- PIC32MZ EF MCU Curiosity Board for data collection
- SAR ADC Utility PC Graphical User Interface (GUI)
Pricing and Availability
Pricing for the new SAR ADCS range from the MCP33111 is available for $1.45 each in 10,000-unit quantities, and the MCP33131 is available for $4.65 each in 10,000-unit quantities. Each ADC comes in either the 10-MSOP with leads in a 3mm X 3mm package or 10-TDFN no leads 3mm X 3mm package.
The 9 mm2 size is the smallest footprint available in the market for a 16-bit, 1 Msps differential ADC. Pricing for the MCP6D11 is $1.17 in 10,000-unit quantities and is available in the 8-MSOP or 3 mm x 3 mm 16-QFN package. The MCP331x1(D)-xx Evaluation Kit is available for $175.