LM12L438 Datasheet | National Semiconductor

Description The LM12434 and LM12 L 438 are highly integrated Data Acquisition Systems Operating on 3V to 5V they bine a fully-differential self-calibrating (correcting linearity and zero errors) 13-bit (12-bit a sign) analog-to-digital converter (ADC) and sample-and-hold (S H) with extensive analog and digital functionality Up to 32 consecutive conversions using two’s plement format can be stored in an internal 32-word (16-bit wide) FIFO data buffer An internal 8-word instruction RAM can store the conversion sequence for up to eight acquisitions through the LM12 L 438’s eight-input multiplexer The LM12434 has a four-channel multiplexer a differential multiplexer output and a differential S H input The LM12434 and LM12 L 438 can also operate with 8-bit a sign resolution and in a supervisory ‘‘watchdog’’ mode that pares an input signal against two programmable limits Acquisition times and conversion rates are programmable through the use of internal clock-driven timers The differential reference voltage inputs can be externally driven for absolute or ratiometric operation All registers RAM and FIFO are directly accessible through the high speed and flexible serial I O interface bus The serial interface bus is user selectable to interface with the following protocols with zero glue logic MICROWIRE PLUSTM Motorola’s SPI QSPI Hitachi’s SCI 8051 Family’s Serial Port (Mode 0) I2C and the TMS320 Family’s Serial Port An evaluation kit for demonstrating the LM12434 and LM12 L 438 is available TRI-STATE is a registered trademark of National Semiconductor Corporation MICROWIRE PLUSTM is a trademark of National Semiconductor Corporation Windows is a registered trademark of Microsoft Corporation Key Specifications f CLK e 8 MHz L f CLK e 6 MHz Y Resolution 12-bit a sign or 8-bit a sign Y 13-bit conversion time 5 5 ms 7 3 ms (max) Y 9-bit conversion time 2 6 ms 3 5 ms (max) Y 13-bit Through-put rate 140k samples s 105k sample s (min) Y parison time (‘‘watchdog’’ mode) 1...