12-BIT 500ksps ADC LTC2308 Low Noise, 500ksps, 8-Channel, 12-Bit ADC FEATURES DESCRIPTION n 12-Bit Resolution The LTC 2308 is a low noise, 500ksps, 8-channel, 12-bit n 500ksps Sampling Rate ADC with an SPI/MICROWIRE compatible serial interface. n Low Noise: SINAD = 73.3dB This ADC includes an internal reference and a fully differ- n Guaranteed No Missing Codes ential sample-and-hold circuit to reduce common mode n Single 5V Supply noise. The internal conversion clock allows the external n Auto-Shutdown Scales Supply Current with Sample serial output data clock (SCK) to operate at any frequency Rate up to 40MHz. n Low Power: 17.5mW at 500ksps The LTC2308 operates from a single 5V supply and draws 0.9mW Nap Mode just 3.5mA at a sample rate of 500ksps. The auto-shutdown 35W Sleep Mode feature reduces the supply current to 200A at a sample n Internal Reference rate of 1ksps. n Internal 8-Channel Multiplexer n The LTC2308 is packaged in a small 24-pin 4mm 4mm Internal Conversion Clock TM n QFN. The internal 2.5V reference and 8-channel multiplexer SPI/MICROWIRE Compatible Serial Interface n further reduce PCB board space requirements. Unipolar or Bipolar Input Ranges (Software Selectable) n Separate Output Supply OV (2.7V to 5.25V) DD The low power consumption and small size make the n 24-Pin 4mm 4mm QFN Package LTC2308 ideal for battery operated and portable appli- cations, while the 4-wire SPI compatible serial interface APPLICATIONS makes this ADC a good match for isolated or remote data acquisition systems. n High Speed Data Acquisition L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear n Industrial Process Control Technology Corporation. All other trademarks are the property of their respective owners. n Motor Control n Accelerometer Measurements n Battery Operated Instruments n Isolated and/or Remote Data Acquisition TYPICAL APPLICATION 5V 8192 Point FFT, f = 1kHz IN 0.1F 10F 10F 0.1F 0 f = 500kHz SMPL 10 AV DV OV 2.7V TO 5.25 V SINAD = 73.6dB DD DD DD 20 CH0 THD = 89.5dB 0.1F LTC2308 30 CH1 40 CH2 50 SDI 60 ANALOG CH3 + SERIAL DATA LINK TO SDO SERIAL CH0-CH7 INPUT 70 ASIC, PLD, MPU, DSP ANALOG INPUTS CH4 PORT MUX SCK 80 OR SHIFT REGISTER 0V TO 4.096V UNIPOLAR 90 CH5 2.048V BIPOLAR CONVST 100 CH6 V REF 110 CH7 INTERNAL 2.2F 120 2.5V REF 130 COM 140 0 50 100 150 200 250 FREQUENCY (kHz) REFCOMP 2308 TA01b GND 0.1F 10F 2308 TA01 2308fc 1 For more information www.linear.com/LTC2308 MAGNITUDE (dB)LTC2308 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Notes 1, 2) TOP VIEW Supply Voltage (AV , DV , OV ) ...........................6V DD DD DD Analog Input Voltage (Note 3) 24 23 22 21 20 19 CH0-CH7, COM, REF, CH3 1 18 GND REFCOMP ...................(GND 0.3V) to (AV + 0.3V) DD CH4 2 17 SD0 Digital Input Voltage CH5 3 16 SCK 25 (Note 3) .......................... (GND 0.3V) to (DV + 0.3V) DD CH6 4 15 SDI Digital Output Voltage .... (GND 0.3V) to (OV + 0.3V) DD CH7 5 14 CONVST Power Dissipation .............................................. 500mW COM 6 13 AV DD Operating Temperature Range 7 8 9 10 11 12 LTC2308C ................................................ 0C to 70C LTC2308I .............................................40C to 85C Storage Temperature Range .................. 65C to 150C UF PACKAGE 24-LEAD (4mm 4mm) PLASTIC QFN T = 150C, = 37C/W JMAX JA EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION