LTC2444/LTC2445/ LTC2448/LTC2449 24-Bit High Speed 8-/16-Channel ADCs with Selectable Speed/Resolution Fea T Descrip T n Up to 8 Differential or 16 Single-Ended Input Channels The LTC 2444/LTC2445/LTC2448/LTC2449 are 8-/16- n Up to 8kHz Output Rate (External f ) channel (4-/8-differential) high speed 24-bit No Latency O n Up to 4kHz Multiplexing Rate (External f ) ADCs. They use a proprietary delta-sigma architec- O n Selectable Speed/Resolution ture enabling variable speed/resolution. Through a simple n 2V Noise at 1.76kHz Output Rate 4-wire serial interface, ten speed/resolution combinations RMS n 200nV Noise at 13.8Hz Output Rate with 6.9Hz/280nV to 3.5kHz/25V (4kHz with external RMS RMS RMS Simultaneous 50Hz/60Hz Rejection oscillator) can be selected with no latency between con- n Guaranteed Modulator Stability and Lock-Up version results or shift in DC accuracy (offset, full-scale, Immunity for any Input and Reference Conditions linearity, drift). Additionally, a 2X speed mode can be n 0.0005% INL, No Missing Codes selected enabling output rates up to 7kHz (8kHz if an n Autosleep Enables 20A Operation at 6.9Hz external oscillator is used) with one cycle latency. n <5V Offset (4.5V < V < 5.5V, 40C to 85C) CC Any combination of single-ended or differential inputs n Differential Input and Differential Reference with can be selected with a common mode input range from GND to V Common Mode Range CC ground to V , independent of V . While operating in CC REF n No Latency Mode, Each Conversion is Accurate Even the 1X speed mode the first conversion following a new After a New Channel is Selected speed, resolution, or channel selection is valid. Since n Internal OscillatorNo External Components there is no settling time between conversions, all 8 dif- n LTC2445/LTC2449 Include MUXOUT/ADCIN for ferential channels can be scanned at a rate of 500Hz. External Buffering or Gain At the conclusion of each conversion, the converter is n Tiny QFN 5mm 7mm Package internally reset eliminating any memory effects between successive conversions and assuring stability of the high a T order delta-sigma modulator. n High Speed Multiplexing L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and n Weight Scales No Latency and SoftSpan are trademarks of Linear Technology Corporation. All other n trademarks are the property of their respective owners. Auto Ranging 6-Digit DVMs n Direct Temperature Measurement n High Speed Data Acquisition Typical a T LTC2444/LTC2448 RMS Noise vs Speed Simple 24-Bit Variable Speed Data Acquisition System 100 4.5V TO 5.5V V = 5V CC V = 5V REF + 1F V = V = 0V IN IN 2X SPEED MODE + REF V CC CH0 = EXTERNAL OSCILLATOR NO LATENCY MODE 10 CH1 = INTERNAL OSCILLATOR F O (SIMULTANEOUS 50Hz/60Hz 2.8V AT 880Hz REJECTION AT 6.9Hz OUTPUT RATE) CH7 SDI 280nV AT 6.9Hz 16-CHANNEL VARIABLE SPEED/ CH8 (50/60Hz REJECTION) + MUX SCK RESOLUTION 4-WIRE 1 THERMOCOUPLE DIFFERENTIAL SDO SPI INTERFACE 24-BIT ADC CS CH15 COM 0.1 1 10 100 1000 10000 REF CONVERSION RATE (Hz) GND LTC2448 2440 TA01b 2444 TA01a 2444589fc 1 For more information www.linear.com/LTC2444 RMS NOISE (V) ion pplica ions pplica ion uresLTC2444/LTC2445/ LTC2448/LTC2449 a Te Maxi Mu M r a T (Notes 1, 2) Supply Voltage (V ) to GND .......................0.3V to 6V Operating Temperature Range CC Analog Input Pins Voltage LTC2444C/LTC2445C/ to GND ......................................0.3V to (V + 0.3V) LTC2448C/LTC2449C ............................... 0C to 70C CC Reference Input Pins Voltage LTC2444I/LTC2445I/ to GND ......................................0.3V to (V + 0.3V) LTC2448I/LTC2449I .............................40C to 85C CC Digital Input Voltage to GND .........0.3V to (V + 0.3V) Storage Temperature Range .................. 65C to 150C CC Digital Output Voltage to GND .......0.3V to (V + 0.3V) CC p in c F T LTC2444 LTC2445 TOP VIEW TOP VIEW 38 37 36 35 34 33 32 38 37 36 35 34 33 32 GND 1 31 GND GND 1 31 GND BUSY 2 30 REF BUSY 2 30 REF + + EXT REF EXT REF 3 29 3 29 GND 28 V GND 28 V 4 CC 4 CC GND 5 27 NC GND 5 27 MUXOUTN 39 39 GND 6 26 NC GND 6 26 ADCINN COM 7 25 NC COM 7 25 ADCINP NC 8 24 NC NC 8 24 MUXOUTP CH0 9 23 NC CH0 9 23 NC CH1 10 22 CH7 CH1 10 22 CH7 NC 11 21 CH6 NC 11 21 CH6 NC 12 20 NC NC 12 20 NC 13 14 15 16 17 18 19 13 14 15 16 17 18 19 UHF PACKAGE UHF PACKAGE 38-LEAD (5mm 7mm) PLASTIC QFN 38-LEAD (5mm 7mm) PLASTIC QFN T = 125C, = 34C/W T = 125C, = 34C/W JMAX JA JMAX JA EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB LTC2448 LTC2449 TOP VIEW TOP VIEW 38 37 36 35 34 33 32 38 37 36 35 34 33 32 GND 1 31 GND GND 1 31 GND BUSY 2 30 REF BUSY 2 30 REF + + EXT REF EXT REF 3 29 3 29 GND V GND V 4 28 4 28 CC CC GND 5 27 NC GND 5 27 MUXOUTN GND 6 39 26 NC GND 6 26 ADCINN 39 COM 7 25 NC COM 7 25 ADCINP CH0 8 24 NC CH0 8 24 MUXOUTP CH1 9 23 CH15 CH1 9 23 CH15 CH2 10 22 CH14 CH2 10 22 CH14 21 CH13 21 CH13 CH3 11 CH3 11 CH4 12 20 CH12 CH4 12 20 CH12 13 14 15 16 17 18 19 13 14 15 16 17 18 19 UHF PACKAGE UHF PACKAGE 38-LEAD (5mm 7mm) PLASTIC QFN 38-LEAD (5mm 7mm) PLASTIC QFN T = 125C, = 34C/W T = 125C, = 34C/W JMAX JA JMAX JA EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB 2444589fc 2 For more information www.linear.com/LTC2444 CH5 SCK CH2 SCK CH6 SDO CH3 SDO CH7 CS NC CS CH8 F NC F O O CH9 SDI CH4 SDI CH10 GND CH5 GND CH11 GND NC GND CH5 SCK CH2 SCK CH6 SDO CH3 SDO CH7 CS NC CS CH8 F NC F O O CH9 SDI CH4 SDI GND GND CH10 CH5 CH11 GND NC GND ion igura on ings bsolu