LTC1746 LINER [Linear Technology], LTC1746 Datasheet
LTC1746
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LTC1746 Summary of contents
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... Pin selectable input ranges of 1V and 1.6V along with a resistor programmable mode allow the LTC1746’s input range to be optimized for a wide variety of applications. The LTC1746 is perfect for demanding communications applications with AC performance that includes 77.5dB SNR and 91dB spurious free dynamic range ...
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... Digital Output Voltage ................. – 0. OGND Voltage ..............................................– 0. Power Dissipation ............................................ 2000mW Operating Temperature Range LTC1746C ............................................... LTC1746I ............................................ – Storage Temperature Range ................. – 150 C Lead Temperature (Soldering, 10 sec).................. 300 VERTER CHARACTERISTICS temperature range, otherwise specifications are at T ...
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... Input Signal, First 5 Harmonics (3.2V Range 4MHz 5.1MHz (2V Range) IN1 IN2 f = 4MHz 5.1MHz (3.2V Range) IN1 IN2 SOURCE (Note 5) CONDITIONS OUT OUT 4.75V V 5.25V DD 1mA I 1mA OUT LTC1746 MIN TYP MAX UNITS 74 dBFS 75.5 77.5 dBFS 73.5 dBFS 76.5 dBFS 72.5 dBFS 75 dBFS 86 ...
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... LTC1746 U U DIGITAL I PUTS A D DIGITAL OUTPUTS operating temperature range, otherwise specifications are at T SYMBOL PARAMETER V High Level Input Voltage IH V Low Level Input Voltage IL I Digital Input Current IN C Digital Input Capacitance IN V High Level Output Voltage OH V Low Level Output Voltage ...
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... FREQUENCY (MHz) 1746 G08 LTC1746 Nonaveraged, 32768 Point FFT, Input Frequency = 5MHz, 3.2V Range 0 –10 –20 –30 –40 –50 –60 –70 –80 –90 –100 –110 –120 ...
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... LTC1746 W U TYPICAL PERFOR A CE CHARACTERISTICS Grounded Input Histogram 25000 20000 15000 10000 5000 0 8167 8168 8169 8170 8171 8172 CODE 1746 G10 SNR vs Input Frequency and Amplitude 3.2V Range 80 –1dBFS 75 –6dBFS –20dBFS INPUT FREQUENCY (MHz) SFDR vs Input Frequency and Amplitude, 3 ...
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... SFDR dBFS 90 80 SFDR dBc 70 60 –20 –60 –40 0 INPUT AMPLITUDE (dBFS) 1746 G21 LTC1746 Worst Harmonic 4th or Higher vs Input Frequency, 3.2V Range, –1dB –60 –70 –80 –90 –100 –110 100 INPUT FREQUENCY (MHz) 1746 G19 ...
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... LTC1746 CTIO S SENSE (Pin 1): Reference Sense Pin. Ground selects 1V. V selects 1.6V. Greater than 1V and less than DD 1.6V applied to the SENSE pin selects an input range 1.6V is the largest valid input range. SENSE V (Pin 2): 2.35V Output and Input Common Mode Bias. CM Bypass to ground with 4.7 F ceramic chip capacitor. ...
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... DATA N D11 TO D0, OF AND CLKOUT W S/H 14-BIT AMP PIPELINED ADC DIFF AMP REFLB REFHA REFLA REFHB 4.7 F 0 LTC1746 DATA (N – 4) DATA (N – 3) D11 TO D0 D11 TO D0 1746 0 D13 OUTPUT • • • LATCHES D0 CLKOUT OGND V ...
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... LTC1746 U U APPLICATIO S I FOR ATIO DYNAMIC PERFORMANCE Signal-to-Noise Plus Distortion Ratio The signal-to-noise plus distortion ratio [ D)] is the ratio between the RMS amplitude of the fundamental input frequency and the RMS amplitude of all other frequency components at the ADC output. The output is band limited to frequencies above DC to below half the sampling frequency ...
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... U U APPLICATIO S I FOR ATIO CONVERTER OPERATION As shown in Figure 1, the LTC1746 is a CMOS pipelined multistep converter. The converter has four pipelined ADC stages; a sampled analog input will result in a digitized value five cycles later, see the Timing Diagram section. The analog input is differential for improved common mode noise immunity and to maximize the input range ...
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... SAMPLE/HOLD OPERATION AND INPUT DRIVE Sample Hold Operation Figure 2 shows an equivalent circuit for the LTC1746 CMOS differential sample-and-hold. The differential ana- log inputs are sampled directly onto sampling capacitors (C ) through CMOS transmission gates ...
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... Conversion Using a Transformer W U Input Drive Circuits Figure 3 shows the LTC1746 being driven transformer with a center tapped secondary. The second- ary center tap is DC biased with V signal at its optimum DC level. Figure 3 shows a 1:1 turns ratio transformer. Other turns ratios can be used if the ...
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... U U APPLICATIO S I FOR ATIO Reference Operation Figure 5 shows the LTC1746 reference circuitry consisting of a 2.35V bandgap reference, a difference amplifier and switching and control circuit. The internal voltage refer- ence can be configured for two pin selectable input ranges of 2V( 1V differential) or 3.2V( 1.6V differential). Tying the SENSE pin to ground selects the 2V range ...
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... Not Recommended for Low Jitter W U Driving the Encode Inputs The noise performance of the LTC1746 can depend on the encode signal quality as much as on the analog input. The ENC/ENC inputs are intended to be driven differentially, primarily for noise immunity from common mode noise sources ...
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... DD single-ended drive. Maximum and Minimum Encode Rates The maximum encode rate for the LTC1746 is 25Msps. For the ADC to operate properly the encode signal should have a 50% ( 5%) duty cycle. Each half cycle must have at least 19ns for the ADC internal circuitry to have enough settling time for proper operation ...
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... The output Hi-Z state is intended for use during long periods of inactivity. GROUNDING AND BYPASSING The LTC1746 requires a printed circuit board with a clean unbroken ground plane. A multilayer board with an inter- nal ground plane is recommended. The pinout of the LTC1746 has been optimized for a flowthrough layout so that the interaction between inputs and digital outputs is minimized ...
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... ADC OGND (Pin 38). HEAT TRANSFER Most of the heat generated by the LTC1746 is transferred from the die through the package leads onto the printed circuit board. In particular, ground pins 12, 13, 36 and 37 are fused to the die attach pad. These pins have the lowest thermal resistance between the die and the outside envi- ronment ...
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... BSC LTC1746 (.311 – .327) 1.20 (.0473) MAX 0.17 – 0.27 0.05 – 0.15 (.002 – .006) 7.9 – 8.3 -T- ...
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... Low Power, 79dB SINAD, 91dB SFDR Pin Compatible with the LTC1746 Pin Compatible with the LTC1746 Pin Compatible with the LTC1746 Pin Compatible with the LTC1746 Pin Compatible with the LTC1746 Pin Compatible with the LTC1746 Pin Compatible with the LTC1746 www.linear.com 1746f LT/TP 0903 1K • ...