ltc2450 Linear Technology Corporation, ltc2450 Datasheet
ltc2450
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ltc2450 Summary of contents
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... The LTC2450 includes a proprietary input sampling scheme that reduces the average input sampling current several orders of magnitude. The LTC2450 is capable conversions per sec- ond and, due to the very large oversampling ratio, has extremely relaxed antialiasing requirements. The LTC2450 ...
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... IN Digital Input Voltage ......................–0. Digital Output Voltage ...................–0. Operating Temperature Range LTC2450C ................................................ 0°C to 70°C LTC2450I.............................................. –40°C to 85°C Storage Temperature Range ................... –65°C to 150°C Lead Temperature (Soldering, 10sec) ................... 300°C ORDER INFORMATION Lead Free Finish ...
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... Note Note 6: SCK = V Note 7: See Figure 3. Note 8: See Figure 4. = 2.7V to 5.5V CC Note 9: Input sampling current is the average input current drawn from the input sampling network while the LTC2450 is actively sampling the input. LTC2450 MIN TYP MAX l 2.7 5.5 l 350 ...
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... LTC2450 TYPICAL PERFORMANCE CHARACTERISTICS Integral Nonlinearity REF 2.5 2.0 1.5 1.0 0 –45°C, 25°C, 90°C –0.5 A –1.0 –1.5 –2.0 –2.5 –3.0 0 0.5 1.0 1.5 2.0 2.5 INPUT VOLTAGE (V) Maximum INL vs Temperature 5.0 4.5 4.0 3.5 3.0 2 2.0 1 1.0 CC 0.5 0 –50 – TEMPERATURE (°C) Gain Error vs Temperature 5.0 4.5 4.0 3.5 3.0 2 4.1V CC 2.0 1 1.0 0.5 0 –50 –25 ...
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... G09 Conversion Period vs Temperature 5V, 4.1V –45 –25 – TEMPERATURE (°C) LTC2450 Conversion Mode Power Supply Current vs Temperature 4. –45 –25 – TEMPERATURE (°C) 2450 G08 Average Power Dissipation ...
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... LTC2450 PIN FUNCTIONS V (Pin 1): Positive Supply Voltage and Converter Refer- CC ence Voltage. Bypass to GND (Pin 3) with a 10μF capacitor in parallel with a low series inductance 0.1μF capacitor located as close to the part as possible. V (Pin 2): Analog Input Voltage. IN GND (Pin 3): Ground. Connect to a ground plane through a low impedance connection ...
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... When the chip select input is pulled low (CS = LOW), and SCK is maintained at a HIGH logic level, the LTC2450 will return to a normal power consumption level. During the SLEEP state, the result of the last conversion is held indefi nitely in a static register ...
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... LTC2450 APPLICATIONS INFORMATION Ease of Use The LTC2450 data output has no latency, fi lter settling delay or redundant results associated with the conversion cycle. There is a one-to-one correspondence between the conver- sion and the output data. Therefore, multiplexing multiple analog input voltages requires no special actions. ...
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... An example of such a sequence is shown in Figure 4. Conversion status monitoring, while possible, is not re- quired for LTC2450 as its conversion time is fi xed and equal at approximately 33.3ms (42ms maximum). Therefore, external timing can be used to determine the completion of a conversion cycle. ...
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... A 17th clock pulse is used to trigger a new conversion cycle. Serial Clock Idle-Low (CPOL = 0) Examples In Figure 7, following a conversion cycle the LTC2450 automatically enters the low power sleep state. The user determines data availability (and the end of conversion) based upon external timing. The user then pulls CS low (CS = ↓ ...
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... Examples of Aborting Cycle using CS For some applications the user may wish to abort the I/O cycle and begin a new conversion. If the LTC2450 is in the data output state rising edge clears the remaining data bits from memory, aborts the output cycle and triggers a new conversion ...
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... LTC2450 APPLICATIONS INFORMATION CS SD0 SCK CONVERT LOW I Figure 9. Idle-High (CPOL = 1) Clock and Aborted I/O Example CS SD0 SCK CONVERT SLEEP LOW I Figure 10. Idle-Low (CPOL = 0) Clock and Aborted I/O Example CS SD0 SCK = LOW CONVERT SLEEP LOW I Figure 11. Idle-Low (CPOL = 0) Clock and Minimum Data Output Length Example ...
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... APPLICATIONS INFORMATION 2-Wire Operation The 2-wire operation modes, while reducing the number of required control signals, should be used only if the LTC2450 low power sleep capability is not required. In addition the option to abort serial data transfers is no longer available. Hardwire CS to GND for 2-wire operation. ...
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... GND and overshoot to less than 0.3V above V Noisy external circuitry can potentially impact the output under 2-wire operation. In particular possible to get the LTC2450 into an unknown state if an SCK pulse is missed or noise triggers an extra SCK pulse. In this situ- ation impossible to distinguish SDO = 1 (indicating conversion in progress) from valid “ ...
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... R capacitor C There are some immediate trade-offs in R needing a full circuit analysis. Increasing R give the following benefi ts: 1) Due to the LTC2450’s input sampling algorithm, the input current drawn by V pin, passing through 50nA. A high R components of the input current, and R 1kΩ ...
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... IN In some cases, R can be increased above these guidelines the case of the LTC2450, in the fi rst half of the CONVERT state, the internal calibration algorithm maintains I strictly at zero. Each half of the CONVERT state is about 16.67ms. Additionally, the input current is zero while the ...
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... LTC2450 noise fl oor (≈2μV Aliasing The LTC2450 signal acquisition circuit is a sampled data system and as such suffers from input signal aliasing. As can be seen from Figure 19, due to the very high over- ...
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... LTC2450 TYPICAL APPLICATION THERMISTOR 18 Thermistor Measurement 5V V 10k CC V LTC2450 IN 100nF 1k TO 10k GND 2450 TA02 CS SCK SDO 2450fb ...
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... ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE LTC2450 0.38 ± 0. PIN 1 CHAMFER OF ...
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... C Easy Drive Input Current Cancellation, 600nV Tiny 10-Lead DFN Package 550nV 20ppm/°C Maximum Drift, 0.2% Maximum www.linear.com ● Easy Passive Input R < 10k S LTC2450 100nF 2450 TA05 Noise, 8kHz Output Rate, 15ppm INL RMS Noise, RMS Noise, RMS Noise, RMS Noise, ...