Maxim tries its hand at a programmable analog arrays

June 16, 2014

Bernard Cole-June 16, 2014

Taking one step back in order to take several forward, Maxim Integrated Products this week introduced its MAX11300 Programmable Mixed Signal I/O (PIXI) device.

Rather than try to create an array of programmable analog elements that could be programmed via some sort of fusible link technology into an arrsy of designed functions - such as amplifiers, filters, comparators, adders , integrators or differentiators - the company has taken a bold step backward.

Instead of a programmable array of analog functions, the company's engineers have created in the MAX11300, which at its core contains a serial digital interface (SPI or I2C) and digital control core, which can be used to configure the device to read values from the input ports, and to write values to the output ports. The 20 port device incorporates an internal temperature sensor and two external temperature sensors, whose values can be accessed by the digital control core and passed to the larger system via the SPI/I2C interface.

The MAX11300 PIXI is in essence a configurable 20-channel, -10V to +10V high-voltage mixed-signal data converter has been targeted by the company at complex applications requiring multiple mixed-signal operations such as cellular and wireless base stations and industrial control and automation. digital-converters/MAX11300.html

Each of the 20 input/output ports is individually configurable with up to four selectable voltage ranges within -10 V to +10 V, and can be configured to be a single-ended analog or digital input or output. Each port that is configured as an analog input is fed to its own 12-bit analog-to-digital converter (ADC) that can support up to 400 Ksps. Similarly, each port that is configured as an analog output is driven by its own 12-bit digital-to-analog converter (DAC).

In the case of ports configured as analog outputs, any adjacent pair of ports can be used to form a differential ADC. Furthermore, any port of such a differential ADC can be internally biased to form a pseudo-differential ADC. (Multiple ADCs can share a common bias point.)

Trying to anticipate the range of end user requirements, Maxim has made it simple to configure.In the case of ports configured as analog outputs, for example, the analog output values can be read back using an internal ADC for correction and calibration. This means that, if the user specifies an output of 6.2 V but the load pulls this down, the user's application can rectify the issue.

Values from any ports configured as analog or digital inputs are read by the MAX11300's digital control block and passed via the SPI or I2C interface out to the larger system. Similarly, the use cases Maxium has worked out assume that values from the larger system are passed via the SPI or I2C interface to the digital control block and written to the ports configured as analog or digital outputs.

The net effect then is that any two PIXI ports can be connected together and used as a uni-directional logic-level translator. The switching threshold of the input may be configured. In addition, the output can be inverted with respect to the input if required.

Also, any two adjacent PIXI ports can be used as a bi-directional logic-level translator. These uni-directional and bi-directional functions are not clocked, so as a result, any change on the port acting as an input will be reflected almost immediately on the corresponding port acting as an output.

Configuration software is a simple "drag and drop" setup of the 20 ports. Files can be exported for coding and easily reconfigured as requirements change. The output of the software tool is a *.csv register configuration file that is used to program the PIXI.

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