MAX1280/MAX1281 Combine 12 analog input multiplexers-EEWORLD

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The MAX1280/MAX1281 12-bit ADCs combine an 8-channel analog input multiplexer , a high-bandwidth sample/hold, and a serial interface with high conversion speed and low power consumption. The MAX1280 operates from a single +4.5 V to +5.5 V supply, and the MAX1281 operates from a single +2.7 V to +3.6 V supply. The analog inputs of both devices can be configured via software for unipolar/bipolar and single-ended/pseudo-differential operation.

The 4-wire serial interface connects directly to SPI™/QSPI™/MICROWIRE™ devices without external logic. A serial trigger output allows direct connection to a TMS320 family digital signal processor. The MAX1280/MAX1281 serial interface uses an external clock to perform successive approximation analog-to-digital conversion. Both devices have an internal +2.5 V reference and a reference buffer amplifier with a ±1.5% voltage adjustment range. An external reference with a 1V to VDD1 range can also be used.

The MAX1280/MAX1281 offer a hardwired low SHDN pin and four software-selectable power modes (normal operation, reduced power, fast power-down, and clean power-down). The devices can be programmed to automatically shut down at the end of a conversion or to operate while reducing power consumption. When using power-down mode, accessing the serial interface automatically turns the devices on, and a fast turn-on time allows them to be powered down between all conversions. This technique can save supply current by reducing the sampling rate to less than 100uA.

The MAX1280/MAX1281 are available in a 20-pin TSSOP package. These devices are higher-speed versions of the MAX146/MAX147

Key Features

8-channel single-ended or 4-channel pseudo differential input

Internal multiplexer and sample/hold

Single power supply

4.5V to 5.5V (MAX1280)

2.7V to 3.6V (MAX1281)

Internal 2.5V reference

400ksps sampling rate (MAX1280)

Low power consumption of 2.5mA (400ksps)

1.3 mA (reduced power mode)

0.9 mA (fast power saving mode)