(LTC2444 - LTC2449) 24-Bit High Speed 8-/16-Channel ADCs

www.DataSheet4U.com FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ LTC2444/LTC2445/ LTC2448/LTC2449 24-Bit High Speed 8-/16-Channel ∆Σ ADCs with Selectable Speed/Resolution DESCRIPTIO The LTC®2444/LTC2445/LTC2448/LTC2449 are 8-/16channel (4-/8-differential) high speed 24-bit No Latency ∆ΣTM ADCs. They use a proprietary delta-sigma architecture enabling variable speed/resolution. Through a simple 4-wire serial interface, ten speed/resolution combinations 6.9Hz/280nVRMS to 3.5kHz/25µVRMS (4kHz with external oscillator) can be selected with no latency between conversion results or shift in DC accuracy (offset, full-scale, linearity, drift). Additionally, a 2X speed mode can be selected enabling output rates up to 7kHz (8kHz if an external oscillator is used) with one cycle latency. Any combination of single-ended or differential inputs can be selected with a common mode input range from ground to VCC, independent of VREF. While operating in the 1X speed mode the first conversion following a new speed, resolution, or channel selection is valid. Since there is no settling time between conversions, all 8 differential channels can be scanned at a rate of 500Hz. At the conclusion of each conversion, the converter is internally reset eliminating any memory effects between successive conversions and assuring stability of the high order delta-sigma modulator. , LTC and LT are registered trademarks of Linear Technology Corporation. No Latency ∆Σ is a trademark of Linear Technology Corporation. Up to 8 Differential or 16 Single-Ended Input Channels Up to 8kHz Output Rate Up to 4kHz Multiplexing Rate Selectable Speed/Resolution 2µVRMS Noise at 1.76kHz Output Rate 200nVRMS Noise at 13.8Hz Output Rate with Simultaneous 50/60Hz Rejection Guaranteed Modulator Stability and Lock-Up Immunity for any Input and Reference Conditions 0.0005% INL, No Missing Codes Autosleep Enables 20µA Operation at 6.9Hz < 5µV Offset (4.5V < VCC < 5.5V, – 40°C to 85°C) Differential Input and Differential Reference with GND to VCC Common Mode Range No Latency Mode, Each Conversion is Accurate Even After a New Channel is Selected Internal Oscillator—No External Components LTC2445/LTC2449 Include MUXOUT/ADCIN for External Buffering or Gain Tiny QFN 5mm x 7mm Package APPLICATIO S ■ ■ ■ ■ ■ High Speed Multiplexing Weight Scales Auto Ranging 6-Digit DVMs Direct Temperature Measurement High Speed Data Acquisition TYPICAL APPLICATIO Simple 24-Bit Variable Speed Data Acquisition System 4.5V TO 5.5V 1µF CH0 CH1 • • • CH7 CH8 • • • CH15 COM REF – GND LTC2448 2444 TA01 REF + VCC FO RMS NOISE (µV) = EXTERNAL OSCILLATOR = INTERNAL OSCILLATOR (SIMULTANEOUS 50Hz/60Hz REJECTION AT 6.9Hz OUTPUT RATE) 4-WIRE SPI INTERFACE THERMOCOUPLE 16-CHANNEL MUX + – VARIABLE SPEED/ RESOLUTION DIFFERENTIAL 24-BIT ∆Σ ADC SDI SCK SDO CS U U U LTC2444/LTC2448 Speed vs RMS Noise 100 VCC = 5V VREF = 5V VIN+ = VIN– = 0V 2X SPEED MODE NO LATENCY MODE 2.8µV AT 880Hz 280nV AT 6.9Hz (50/60Hz REJECTION) 10 1 0.1 1 1000 10 100 CONVERSION RATE (Hz) 10000 2440 TA02 sn2444589 2444589fs 1 LTC2444/LTC2445/ LTC2448/LTC2449 ABSOLUTE (Notes 1, 2) AXI U RATI GS Operating Temperature Range LTC2444C/LTC2445C/ LTC2448C/LTC2449C .............................. 0°C to 70°C LTC2444I/LTC2445I/ LTC2448I/LTC2449I ........................... – 40°C to 85°C Storage Temperature Range ................. – 65°C to 125°C Supply Voltage (VCC) to GND .......................– 0.3V to 6V Analog Input Pins Voltage to GND .................................... – 0.3V to (VCC + 0.3V) Reference Input Pins Voltage to GND .................................... – 0.3V to (VCC + 0.3V) Digital Input Voltage to GND ........ – 0.3V to (VCC + 0.3V) Digital Output Voltage to GND ..... – 0.3V to (VCC + 0.3V) PACKAGE/ORDER I FOR ATIO TOP VIEW GND GND SDO SCK SDI CS FO GND 38 37 36 35 34 33 32 GND 1 BUSY 2 EXT 3 GND 4 GND 5 GND 6 COM 7 NC 8 CH0 9 CH1 10 NC 11 NC 12 13 14 15 16 17 18 19 NC NC CH2 CH3 CH4 CH5 NC 31 GND 30 REF– 29 REF+ 28 VCC 27 NC 26 NC 25 NC 24 NC 23 NC 22 CH7 21 CH6 20 NC LTC2444CUHF LTC2444IUHF 38 37 36 35 34 33 32 GND 1 BUSY 2 EXT 3 GND 4 GND 5 GND 6 COM 7 NC 8 31 GND 30 REF– 29 REF+ 28 VCC 27 MUXOUTN 26 ADCINN 25 ADCINP 24 MUXOUTP 23 NC 22 CH7 21 CH6 20 NC 13 14 15 16 17 18 19 NC NC CH2 CH3 CH4 CH5 NC GND SDO SCK SDI CS FO ORDER PART NUMBER QFN PART MARKING* 2444 UHF PACKAGE 38-LEAD (5mm × 7mm) PLASTIC QFN TJMAX = 125°C, θJA = 34°C/W TOP VIEW GND GND SDO SCK SDI CS FO 38 37 36 35 34 33 32 GND 1 BUSY 2 EXT 3 GND 4 GND 5 GND 6 COM 7 CH0 8 CH1 9 CH2 10 CH3 11 CH4 12 13 14 15 16 17 18 19 CH5 CH6 CH7 CH8 CH9 CH10 CH11 31 GND 30 REF– 29 REF+ 28 VCC 27 NC 26 NC 25 NC 24 NC 23 CH15 22 CH14 21 CH13 20 CH12 ORDER PART NUMBER LTC2448CUHF LTC2448IUHF GND 38 37 36 35 34 33 32 GND 1 BUSY 2 EXT 3 GND 4 GND 5 GND 6 COM 7 CH0 8 31 GND 30 REF– 29 REF+ 28 VCC 27 MUXOUTN 26 ADCINN 25 ADCINP 24 MUXOUTP 23 CH15 22 CH14 21 CH13 20 CH12 13 14 15 16 17 18 19 GND SDO SCK SDI CS FO QFN PART MARKING* 2448 CH5 CH6 CH7 CH8 CH9 CH10 UHF PACKAGE 38-LEAD (5mm × 7mm) PLASTIC QFN UHF PACKAGE 38-LEAD (5mm × 7mm) PLASTIC QFN TJMAX = 125°C, θJA = 34°C/W TJMAX = 125°C, θJA = 34°C/W *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for parts specified with wider operating temperature ranges. sn2444589 2444589fs 2 CH11 U U W WW U W TOP VIEW ORDER PART NUMBER LTC2445CUHF LTC2445IUHF CH0 9 CH1 10 NC 11 NC 12 QFN PART MARKING* 2445 UHF PACKAGE 38-LEAD (5mm × 7mm) PLASTIC QFN TJMAX = 125°C, θJA = 34°C/W TOP VIEW ORDER PART NUMBER LTC2449CUHF LTC2449IUHF CH1 9 CH2 10 CH3 11 CH4 12 QFN PART MARKING* 2449 LTC2444/LTC2445/ LTC2448/LTC2449 The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Notes 3, 4) PARAMETER Resolution (No Missing Codes) Integral Nonlinearity Offset Error Offset Error Drift Positive Full-Scale Error Positive Full-Scale Error Drift Negative Full-Scale Error Negative Full-Scale Error Drift Total Unadjusted Error CONDITIONS 0.1V ≤ VREF ≤ VCC, –0.5 • VREF ≤ VIN ≤ 0.5 • VREF, (Note 5) VCC = 5V, REF+ = 5V, REF– = GND, VINCM = 2.5V, (Note 6) REF+ = 2.5V, REF– = GND, VINCM = 1.25V, (Note 6) 2.5V ≤ REF+ ≤ VCC, REF– = GND, GND ≤ IN+ = IN– ≤ VCC (Note 12) 2.5V ≤ REF+ ≤ VCC, REF– = GND, GND ≤ IN+ = IN– ≤ VCC REF + = 5V, REF – = GND, IN + = 3.75V, IN – = 1.25V REF + = 2.5V, REF – = GND, IN + = 1.875V, IN – = 0.625V 2.5V ≤ REF+ ≤ VCC, REF– = GND, IN+ = 0.75REF+, IN– = 0.25 • REF+ REF + = 5V, REF – = GND, IN + = 1.25V, IN – = 3.75V REF + = 2.5V, REF – = GND, IN + = 0.625V, IN – = 1.875V 2.5V ≤ REF+ ≤ VCC, REF– = GND, IN+ = 0.25 • REF+, IN– = 0.75 • REF+ 5V ≤ VCC ≤ 5.5V, REF+ = 2.5V, REF– = GND, VINCM = 1.25V 5V ≤ VCC ≤ 5.5V, REF+ = 5V, REF– = GND, VINCM = 2.5V REF+ = 2.5V, REF– = GND, VINCM = 1.25V, (Note 6) 2.5V ≤ REF+ ≤ VCC, REF– = GND, GND ≤ IN– = IN+ ≤ VCC ● ● ● ● ● ● ● ELECTRICAL CHARACTERISTICS MIN 24 TYP 5 3 2.5 20 10 10 0.2 10 10 0.2 15 15 15 120 MAX 15 5 UNITS Bits ppm of VREF ppm of VREF µV nV/°C 50 50 ppm of VREF ppm of VREF ppm of VREF/°C 50 50 ppm of VREF ppm of VREF ppm of VREF/°C ppm of VREF ppm of VREF ppm of VREF dB Input Common Mode Rejection DC A ALOG I PUT A D REFERE CE The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3) SYMBOL IN+ IN– VIN REF+ REF– VREF CS(IN+) CS(IN–) CS(REF+) CS(REF–) IDC_LEAK(IN+, IN–, REF+, REF–) PARAMETER Absolute/Common Mode IN+ Voltage Absolute/Common Mode IN– Voltage Input Differential Voltage Range (IN+ – IN–) Absolute/Common Mode REF+ Voltage Absolute/Common Mode REF– Voltage Reference Differential Voltage Range (REF+ – REF–) IN+ Sampling Capacitance IN– Sampling Capacitance REF+ Sampling Capacitance REF– Sampling Capacitance Leakage Current, Inputs and Reference Average Input/Reference Current During Sampling MUX Break-Before-Make MUX Off Isolation ISAMPLE(IN+, IN–, REF+, REF–) tOPEN QIRR U U U U CONDITIONS ● ● ● ● ● ● MIN GND – 0.3V GND – 0.3V –VREF/2 0.1 GND 0.1 TYP MAX VCC + 0.3V VCC + 0.3V VREF/2 VCC VCC – 0.1V VCC UNITS V V V V V V pF pF pF pF 2 2 2 2 CS = VCC, IN+ = GND, IN– REF+ = 5V, REF– = GND = GND, ● –15 1 15 nA nA ns dB Varies, See Applications Section 50 VIN = 2VP-P DC to 1.8MHz 120 sn2444589 2444589fs 3 LTC2444/LTC2445/ LTC2448/LTC2449 DIGITAL I PUTS A D DIGITAL OUTPUTS SYMBOL VIH VIL VIH VIL IIN IIN CIN CIN VOH VOL VOH VOL IOZ PARAMETER High Level Input Voltage CS, FO Low Level Input Voltage CS, FO High Level Input Voltage SCK Low Level Input Voltage SCK Digital Input Current CS, FO, EXT, SOI Digital Input Current SCK Digital Input Capacitance CS, FO Digital Input Capacitance SCK High Level Output Voltage SDO, BUSY Low Level Output Voltage SDO, BUSY High Level Output Voltage SCK Low Level Output Voltage SCK Hi-Z Output Leakage SDO (Note 8) IO = –800µA IO = 1.6mA IO = –800µA (Note 9) IO = 1.6mA (Note 9) ● ● ● ● ● The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3) CONDITIONS 4.5V ≤ VCC ≤ 5.5V 4.5V ≤ VCC ≤ 5.5V 4.5V ≤ VCC ≤ 5.5V (Note 8) 4.5V ≤ VCC ≤ 5.5V (Note 8) 0V ≤ VIN ≤ VCC 0V ≤ VIN ≤ VCC (Note 8) ● ● ● ● ● ● POWER REQUIRE E TS SYMBOL VCC ICC PARAMETER Supply Voltage Supply Current Conversion Mode Sleep Mode The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3) CONDITIONS ● TI I G CHARACTERISTICS SYMBOL fEOSC tHEO tLEO tCONV PARAMETER External Oscilla