ltc2494cuhf-trpbf Linear Technology Corporation, ltc2494cuhf-trpbf Datasheet
ltc2494cuhf-trpbf
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ltc2494cuhf-trpbf Summary of contents
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... LT, LTC and LTM are registered trademarks of Linear Technology Corporation. No Latency ΔS and Easy Drive are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. 2.7V TO 5.5V 0.1µF 10µ ...
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... PLASTIC QFN T EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB ORDER PART NUMBER LTC2494CUHF LTC2494IUHF Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges ...
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T PARAMETER CONDITIONS Resolution (No Missing Codes) 0.1V ≤ V Integral Nonlinearity 5V ≤ V 2.7V ≤ V Offset Error 2.5V ≤ V Offset Error ...
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LTC2494 analog inpuT anD reFerence temperature range, otherwise specifications 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 the ...
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DigiTal inpuTs anD DigiTal ouTpuTs full operating temperature range, otherwise specifications 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 Speed ...
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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 –1 –45°C, 25°C ...
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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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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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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 amplifiers. The remaining common mode input current is eliminated by either balancing the ...
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In order to achieve optimum performance external amplifier is 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 the ...
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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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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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Table 4. Converter Configuration 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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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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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) SDI DON'T CARE 1 0 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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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) DON'T CARE 1 0 SDI EOC “0” SDO 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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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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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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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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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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... ALL DIMENSIONS ARE IN MILLIMETERS Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. UHF Package 38-Lead Plastic QFN (5mm × ...
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... Pin Compatible with LTC2494/LTC2449/LTC2498 Pin Compatible with LTC2494/LTC2496/LTC2449 www.linear.com ● SDI ∆Σ ADC SCK WITH EASY DRIVE SDO INPUTS CS 0.1µF 0.1µF 2494 TA02 Noise, 2ppm INL Noise RMS LT/CGRAFX 0407 REV A • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2007 2494fa ...