LTC2494CUHF-PBF LINER [Linear Technology], LTC2494CUHF-PBF Datasheet
LTC2494CUHF-PBF
Related parts for LTC2494CUHF-PBF
LTC2494CUHF-PBF Summary of contents
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FEATURES Differential or 16 Single-Ended Inputs ■ ■ Easy Drive Technology Enables Rail-to-Rail Inputs with Zero Differential Input Current Directly Digitizes High Impedance Sensors with ■ Full Accuracy 600nV RMS Noise ■ Programmable Gain from 1 to ...
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... ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL LTC2494CUHF#PBF LTC2494CUHF#TRPBF LTC2494IUHF#PBF LTC2494IUHF#TRPBF Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi label on the shipping container. Consult LTC Marketing for information on non-standard lead based fi nish parts. ...
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ELECTRICAL CHARACTERISTICS (NORMAL SPEED) apply over the full operating temperature range, otherwise specifi cations are at T PARAMETER CONDITIONS Resolution (No Missing Codes) 0.1V ≤ V Integral Nonlinearity 5V ≤ V 2.7V ≤ V Offset Error 2.5V ≤ V Offset ...
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LTC2494 ANALOG INPUT AND REFERENCE temperature range, otherwise specifi cations are at T SYMBOL PARAMETER + + IN Absolute/Common Mode IN + (IN Corresponds to the Selected Positive Input Channel) – – IN Absolute/Common Mode IN – (IN Corresponds to ...
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DIGITAL INPUTS AND DIGITAL OUTPUTS full operating temperature range, otherwise specifi cations are at T SYMBOL PARAMETER f External Oscillator Frequency Range EOSC t External Oscillator High Period HEO t External Oscillator Low Period LEO t Conversion Time for 1x ...
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LTC2494 TYPICAL PERFORMANCE CHARACTERISTICS Integral Nonlinearity ( 5V) CC REF REF 2.5V IN(CM GND O 1 –45°C 25°C 0 85°C –1 –2 –3 ...
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TYPICAL PERFORMANCE CHARACTERISTICS RMS Noise vs Input Differential Voltage 1 REF 0 2.5V IN(CM 25°C A 0.8 0.7 0.6 0.5 0.4 –2.5 –2 –1.5 –1 –0.5 0 0.5 1 ...
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LTC2494 TYPICAL PERFORMANCE CHARACTERISTICS On-Chip Oscillator Frequency vs Temperature 310 308 306 304 2.5V REF 302 GND IN(CM GND O 300 –45 –30 – ...
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TYPICAL PERFORMANCE CHARACTERISTICS Integral Nonlinearity (2x Speed Mode 5V 2.5V) CC REF 2.5V REF 1.25V IN(CM GND O 1 85°C 0 –45°C, 25°C –1 ...
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LTC2494 TYPICAL PERFORMANCE CHARACTERISTICS PSRR vs Frequency at V (2x Speed Mode 4.1V DC ±1. REF = 2.5V –20 – REF = GND + IN = GND – – GND F = GND ...
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PIN FUNCTIONS F (Pin 35): Frequency Control Pin. Digital input that O controls the internal conversion clock rate. When F connected to GND, the converter uses its internal oscil- lator running at 307.2kHz. The conversion clock may also be overridden ...
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LTC2494 TEST CIRCUITS SDO 1.69k C LOAD Hi Hi-Z OH TIMING DIAGRAMS Timing Diagram Using Internal SCK (SCK HIGH with CS↓ Hi-Z SDO t 3 SCK SDI ...
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APPLICATIONS INFORMATION CONVERTER OPERATION Converter Operation Cycle The LTC2494 is a multi-channel, low power, delta-sigma, analog-to-digital converter with an easy-to-use, 4-wire interface and automatic differential input current cancella- tion. Its operation is made up of four states (See Figure 2). ...
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LTC2494 APPLICATIONS INFORMATION transparently removes the differential input current. This enables external RC networks and high impedance sen- sors to directly interface to the LTC2494 without external amplifi ers. The remaining common mode input current is eliminated by either balancing ...
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APPLICATIONS INFORMATION In order to achieve optimum performance external amplifi not used, short these pins directly together (ADCINP to MUXOUTP and ADCINN to MUXOUTN) and minimize their capacitance to ground. SERIAL INTERFACE PINS The LTC2494 transmits ...
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LTC2494 APPLICATIONS INFORMATION Bit 22 (second output bit dummy bit (DMY) and is always LOW. Bit 21 (third output bit) is the conversion result sign indicator (SIG). If the selected input (V greater than or equal to 0V, ...
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APPLICATIONS INFORMATION Table 2. LTC2494 Output Data Format DIFFERENTIAL INPUT VOLTAGE BIT EOC ≥ FS FS** – 1LSB 0 0.5 • FS** 0 0.5 • FS** – 1LSB –1LSB ...
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LTC2494 APPLICATIONS INFORMATION Table 3 Channel Selection MUX ADDRESS ODD/ SGL SIGN ...
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APPLICATIONS INFORMATION Table 4. Converter Confi guration SGL ODD EN2 ...
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LTC2494 APPLICATIONS INFORMATION Table 5a. Performance vs Gain in Normal Speed Mode (V GAIN 1 Input Span ±2.5 LSB 38.1 Noise Free Resolution* 65536 Gain Error 5 Offset Error 0.5 Table 5b. Performance vs Gain in 2x Speed Mode (V ...
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APPLICATIONS INFORMATION 1020 REF 960 SLOPE = 2.45 LSB /K 16 800 640 480 320 160 0 0 100 200 300 TEMPERATURE (K) Figure 4. Internal PTAT Digital Output vs Temperature Table 6. ...
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LTC2494 APPLICATIONS INFORMATION CS 1 SCK (EXTERNAL) SDI DON'T CARE 1 Hi-Z SDO EOC BIT 23 BIT 22 CONVERSION SLEEP Typically, CS remains LOW during the data output/input state. However, the data output state may be aborted by pulling CS ...
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APPLICATIONS INFORMATION CS SCK (EXTERNAL) SDI DON'T CARE SDO CONVERSION SLEEP Figure 7. External Serial Clock, Reduced Output Data Length and Valid Channel Selection SCK (EXTERNAL) DON'T CARE 1 0 SDI EOC “0” SDO BIT 23 BIT ...
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LTC2494 APPLICATIONS INFORMATION On the falling edge of EOC, the conversion result is load- ing into an internal static shift register. The output data can now be shifted out the SDO pin under control of the externally applied SCK signal. ...
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APPLICATIONS INFORMATION After the 24th rising edge of SCK a new conversion au- tomatically begins. SDO goes HIGH (EOC = 1) and SCK remains HIGH for the duration of the conversion cycle. Once the conversion is complete, the cycle repeats. ...
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LTC2494 APPLICATIONS INFORMATION SCK (INTERNAL) SDI DON'T CARE 1 0 SDO EOC “0” BIT 23 BIT 22 BIT 21 CONVERSION During the conversion, the SCK and the serial data output pin (SDO) are HIGH (EOC = 1). ...
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APPLICATIONS INFORMATION PRESERVING THE CONVERTER ACCURACY The LTC2494 is designed to reduce as much as possible sensitivity to device decoupling, PCB layout, anti-aliasing circuits, line frequency perturbations, and temperature sensitivity. In order to achieve maximum performance a few simple precautions ...
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LTC2494 APPLICATIONS INFORMATION INPUT EXTERNAL MULTIPLEXER + CONNECTION I IN 100Ω MUXOUTP – 100Ω – IN MUXOUTN EXTERNAL + I CONNECTION REF + REF – I REF – REF SWITCHING FREQUENCY f = 123kHz INTERNAL OSCILLATOR ...
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APPLICATIONS INFORMATION impedances lead to gain errors proportional to the dif- ference between the common mode input and common mode reference. 1% mismatches in 1k source resistances lead to gain errors on the order of 15ppm. Based on the stability ...
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LTC2494 APPLICATIONS INFORMATION REF + V = 3.75V IN 70 – 1.25V GND 25° 0.01μF REF 40 C ...
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APPLICATIONS INFORMATION In addition to the reference sampling charge, the reference ESD projection diodes have a temperature dependent leak- age current. This leakage current, nominally 1nA (±10nA max) results in a small gain error. A 100Ω reference resistance will create ...
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LTC2494 APPLICATIONS INFORMATION The user can expect to achieve this level of performance using the internal oscillator, as shown in Figures 23, 24, and 25. Measured values of normal mode rejection are shown superimposed over the theoretical values in all ...
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APPLICATIONS INFORMATION 0 V IN(P-P) V IN(P-P) –20 (150% OF FULL SCALE) –40 – 60 –80 –100 –120 105 120 135 150 165 180 195 210 225 240 INPUT FREQUENCY (Hz) Figure 26. ...
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LTC2494 APPLICATIONS INFORMATION IN(CM) REF(CM REF EXT CLOCK 85° 25°C A –10 0 ...
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PACKAGE DESCRIPTION 5.50 ± 0.05 (2 SIDES) 4.10 ± 0.05 (2 SIDES) 3.15 ± 0.05 (2 SIDES) 5.00 ± 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) 7.00 ± 0.10 (2 SIDES) 0.75 ± 0.05 NOTE: 1. DRAWING ...
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LTC2494 TYPICAL APPLICATION External Buffers Provide High Impedance Inputs and Amplifi er Offsets are Automatically Cancelled. 17 ANALOG INPUTS RELATED PARTS PART NUMBER DESCRIPTION LT1236A-5 Precision Bandgap Reference, 5V LT1460 Micropower Series Reference LT1790 Micropower SOT-23 Low Dropout Reference Family ...