LTC2415CGN#TRPBF Linear Technology, LTC2415CGN#TRPBF Datasheet
LTC2415CGN#TRPBF
Specifications of LTC2415CGN#TRPBF
Available stocks
Related parts for LTC2415CGN#TRPBF
LTC2415CGN#TRPBF Summary of contents
Page 1
... The LTC2415/LTC2415-1 communicate through a flexible 3-wire digital interface which is compatible with SPI and TM MICROWIRE protocols. , LTC and LT are registered trademarks of Linear Technology Corporation. No Latency is a trademark of Linear Technology Corporation. MICROWIRE is a trademark of National Semiconductor Corporation. BRIDGE IMPEDANCE ...
Page 2
LTC2415/LTC2415 ABSOLUTE AXI U RATI GS (Notes 1, 2) Supply Voltage ( GND .......................– 0. Analog Input Pins Voltage to GND .................................... – 0. Reference Input Pins Voltage to GND ...
Page 3
U CO VERTER CHARACTERISTICS temperature range, otherwise specifications are at T PARAMETER CONDITIONS Input Common Mode Rejection 2.5V REF 60Hz 2% (LTC2415) GND IN Input Common Mode Rejection 2.5V REF 50Hz 2% (LTC2415) GND IN Input Normal Mode Rejection (Note ...
Page 4
LTC2415/LTC2415 DIGITAL I PUTS A D DIGITAL OUTPUTS operating temperature range, otherwise specifications are at T SYMBOL PARAMETER V High Level Input Voltage IH CS Low Level Input Voltage IL CS High ...
Page 5
CHARACTERISTICS 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 (LTC2415) CONV Conversion Time (LTC2415-1) ...
Page 6
LTC2415/LTC2415 TYPICAL PERFOR A CE CHARACTERISTICS Total Unadjusted Error Over Temperature ( 5V) REF 106 REF V = 2.5V 106.0 INCM ...
Page 7
W U TYPICAL PERFOR A CE CHARACTERISTICS Noise Histogram (Output Rate = 15Hz 5V 2.5V) CC REF 12 10,000 CONSECUTIVE GAUSSIAN READINGS DISTRIBUTION –209.2ppm 2.5V = 0.56ppm ...
Page 8
LTC2415/LTC2415 TYPICAL PERFOR A CE CHARACTERISTICS RMS Noise vs V INCM 1800 + INCM – REF INCM GND IN O ...
Page 9
W U TYPICAL PERFOR A CE CHARACTERISTICS +Full-Scale Error 2.5V REF + REF = 2.5V – 4 REF = GND + IN = 1.25V – GND F = GND ...
Page 10
LTC2415/LTC2415 TYPICAL PERFOR A CE CHARACTERISTICS Conversion Current vs Output Data Rate 1000 900 + REF = 5V – REF = GND 800 + IN = GND – 700 IN = GND F = ...
Page 11
CTIO S F (Pin 14): Frequency Control Pin. Digital input that O controls the ADC’s notch frequencies and conversion time. When the F pin is connected the converter uses its internal oscillator ...
Page 12
LTC2415/LTC2415 APPLICATIO S I FOR ATIO CONVERTER OPERATION Converter Operation Cycle The LTC2415/LTC2415-1 are low power, delta-sigma ana- log-to-digital converters with an easy to use 3-wire serial interface (see Figure 1). Their operation is made up of three ...
Page 13
U U APPLICATIO S I FOR ATIO The LTC2415/LTC2415-1 perform a full-scale calibration every conversion cycle. This calibration is transparent to the user and has no effect on the cyclic operation de- scribed above. The advantage of continuous calibration is ...
Page 14
LTC2415/LTC2415 APPLICATIO S I FOR ATIO Output Data Format The LTC2415/LTC2415-1 serial output data stream is 32 bits long. The first 3 bits represent status information indicating the sign and conversion state. The next 24 bits are the ...
Page 15
U U APPLICATIO S I FOR ATIO While the variation in offset with supply voltage is propor- tional to V (see Figure 4), several characteristics of this CC variation can be used to eliminate the effects. First, the variation with ...
Page 16
LTC2415/LTC2415 APPLICATIO S I FOR ATIO Frequency Rejection Selection LTC2415 (F The LTC2415 internal oscillator provides better than 110dB normal mode rejection at the line frequency and its harmon- ics for 50Hz 2% or 60Hz 2%. For 60Hz ...
Page 17
U U APPLICATIO S I FOR ATIO state and the converter is in the Internal SCK mode, the serial clock duty cycle may be affected but the serial data stream will remain valid. Table 3b summarizes the duration of each ...
Page 18
LTC2415/LTC2415 APPLICATIO S I FOR ATIO Serial Clock Input/Output (SCK) The serial clock signal present on SCK (Pin 13) is used to synchronize the data transfer. Each bit of data is shifted out the SDO pin on the ...
Page 19
U U APPLICATIO S I FOR ATIO The serial clock mode is selected on the falling edge of CS. To select the external serial clock mode, the serial clock pin (SCK) must be LOW during each CS falling edge. The ...
Page 20
LTC2415/LTC2415 APPLICATIO S I FOR ATIO CS TEST EOC BIT 0 SDO EOC Hi-Z Hi-Z SCK (EXTERNAL) SLEEP CONVERSION DATA OUTPUT Figure 9. External Serial Clock, Reduced Data Output Length Since CS is tied LOW, the end-of-conversion (EOC) ...
Page 21
U U APPLICATIO S I FOR ATIO CS SDO SCK (EXTERNAL) CONVERSION SLEEP Figure 10. External Serial Clock Operation (2-Wire) <t EOCtest CS TEST EOC BIT 31 SDO EOC Hi-Z Hi-Z SCK (INTERNAL) CONVERSION SLEEP W U ...
Page 22
LTC2415/LTC2415 APPLICATIO S I FOR ATIO by an external oscillator of (LTC2415-1) frequency f then t is 3.6 pulled HIGH before time EOCtest EOSC t , the device remains in the sleep state. The ...
Page 23
U U APPLICATIO S I FOR ATIO A similar situation may occur during the sleep state when CS is pulsed HIGH-LOW-HIGH in order to test the conver- sion status. If the device is in the sleep state (EOC = 0), ...
Page 24
LTC2415/LTC2415 APPLICATIO S I FOR ATIO Internal Serial Clock, Autostart Conversion This timing mode is identical to the internal serial clock, 2-wire I/O described above with one additional feature. Instead of grounding CS, an external timing capacitor is ...
Page 25
U U APPLICATIO S I FOR ATIO 100 1000 10000 CAPACITANCE ON CS (pF) Figure 15. CS Capacitance ...
Page 26
LTC2415/LTC2415 APPLICATIO S I FOR ATIO LTC2415-1 pins may severely disturb the analog to digital conversion process. Undershoot and overshoot can oc- cur because of the impedance mismatch at the converter pin when the transition time of an ...
Page 27
U U APPLICATIO S I FOR ATIO REF R (TYP LEAK 20k V + REF I LEAK (TYP LEAK 20k LEAK V ...
Page 28
LTC2415/LTC2415 APPLICATIO S I FOR ATIO For relatively small values of input capacitance (C 0.01 F), the voltage on the sampling capacitor settles almost completely and relatively large values for the source impedance result in only small errors. ...
Page 29
U U APPLICATIO S I FOR ATIO used for the external source impedance seen by IN – the expected drift of the dynamic current, offset and gain errors will be insignificant (about 1% of their respec- tive values ...
Page 30
LTC2415/LTC2415 APPLICATIO S I FOR ATIO Reference Current In a similar fashion, the LTC2415/LTC2415-1 sample the + differential reference pins REF and REF small amount of charge to and from the external driving circuits thus producing a dynamic ...
Page 31
U U APPLICATIO S I FOR ATIO tance is 1.43M . When F is driven by an external O oscillator with a frequency f EOSC clock operation), the typical differential reference resis- 12 tance is 0.20 • and ...
Page 32
LTC2415/LTC2415 APPLICATIO S I FOR ATIO Normal Mode Rejection, Output Rate and Running Averages The LTC2415/LTC2415-1 both contain an identical Sinc digital filter (see Figures 30 and 31) which offers excellent line frequency noise rejection. For the LTC2415, ...
Page 33
... Figure 39) which graphically cap- tures the conversion results. It can be used to determine noise performance, stability and with an external source, linearity. As exemplified in the schematic, the LTC2415/ LTC2415-1 are extremely easy to use. This demonstra- tion board and associated software is available by con- tacting Linear Technology ...
Page 34
... If the bridge is composed of four equal 350 resistors, the differential component associated with mismatch of R3 and R6 is nearly constant with either polarity of excitation and, as with offset, its contribution is canceled. C-Load is a trademark of Linear Technology Corporation. 4 filter at about 12Hz. The . RMS ...
Page 35
U U APPLICATIO S I FOR ATIO ELIMINATE FOR 5V 1.5k OPERATION (CONNECT 2.7k RESISTORS TO 100 RESISTORS) Q2 100 2.7k 2.7k POL 74HC04 22 22 Figure 37. Correlated Double Sampling Resolves 100nV W U ...
Page 36
LTC2415/LTC2415-1 U TYPICAL APPLICATIO S ************************************************************ * This example program transfers the LTC2415/LTC2415-1 32-bit output * * conversion result into four consecutive 8-bit memory locations. ************************************************************ *68HC11 register definition PORTD EQU $1008 Port D data register * " – , ...
Page 37
U TYPICAL APPLICATIO S ******************************************** * The next short loop waits for the * LTC2415/LTC2415-1’s conversion to finish before * * starting the SPI data transfer ******************************************** * CONVEND LDAA PORTD Retrieve the contents of port D ANDA #%00000100 Look ...
Page 38
LTC2415/LTC2415-1 U TYPICAL APPLICATIO S U PCB LAYOUT A D FIL LTC2415CGN Differential Input 24-Bit ADC with 2 Output Rate Demo Circuit DC382 www.linear-tech.com LTC Confidential For Customer Use Only Silkscreen Top 38 Figure 39. Display Graphic W Top Layer ...
Page 39
... FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 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 represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...
Page 40
... U3D R5 R6 74HC14 49 22k 3 Q1 MMBT3904LT1 2 R8 51k V CC BYPASS CAP C7 FOR U3 0.1 F 2415 F40 Noise P-P Noise, Pin Compatible with LTC2415 RMS Noise, 4ppm INL RMS Noise RMS LT/TP 0202 2K • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2001 sn2415 24151fs ...