LTC2239 Linear Technology Corporation, LTC2239 Datasheet
LTC2239
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LTC2239 Summary of contents
Page 1
... The LTC 2239 is a 10-bit 80Msps, low power 3V A/D converter designed for digitizing high frequency, wide dynamic range signals. The LTC2239 is perfect for de- manding imaging and communications applications with AC performance that includes 61.6dB SNR and 85dB SFDR for signals well beyond the Nyquist frequency. ...
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... Analog Input Voltage (Note 3) ..... –0. Digital Input Voltage .................... –0. Digital Output Voltage ................ –0.3V to (OV Power Dissipation............................................ 1500mW Operating Temperature Range LTC2239C ............................................... 0°C to 70°C LTC2239I .............................................–40°C to 85°C Storage Temperature Range ..................–65°C to 125° VERTER CHARACTERISTICS ...
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... Input 5MHz Input 40MHz Input 70MHz Input 140MHz Input f = 28.2MHz 26.8MHz IN1 IN2 Figure 8 Test Circuit (Note 4) CONDITIONS OUT 2.7V < V < 3.4V DD –1mA < I < 1mA OUT LTC2239 MIN TYP MAX UNITS ±0.5 to ±1 ● V ● 1 1.5 1.9 V ● 0.5 1 µA ● –1 1 µ ...
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... LTC2239 U U DIGITAL I PUTS A D DIGITAL OUTPUTS full operating temperature range, otherwise specifications are at T SYMBOL PARAMETER LOGIC INPUTS (CLK, OE, SHDN) V High Level Input Voltage IH V Low Level Input Voltage IL I Input Current IN C Input Capacitance IN LOGIC OUTPUTS Hi-Z Output Capacitance ...
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... Note 3V differential drive. without latchup. Note 9: Recommended operating conditions. with differential P-P Typical DNL, 2V Range 1.0 0.8 0.6 0.4 0.2 0 –0.2 –0.4 –0.6 –0.8 –1.0 0 256 512 768 CODE LTC2239 MIN TYP MAX ● ● 5.9 6.25 500 ● 5 6.25 500 ● 5.9 6.25 500 ● 5 6.25 500 0 ● 1.4 2 ...
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... LTC2239 W U TYPICAL PERFOR A CE CHARACTERISTICS 8192 Point FFT 30MHz, IN –1dB, 2V Range 0 –10 –20 –30 –40 –50 –60 –70 –80 –90 –100 –110 –120 FREQUENCY (MHz) 2239 G04 8192 Point 2-Tone FFT 28.2MHz and 26.8MHz, IN –1dB, 2V Range 0 – ...
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... G13 RANGE 100 2239 G15 LTC2239 = 70MHz, IN dBFS dBc –10 0 –40 –30 –20 INPUT LEVEL (dBFS) 2239 G14 I vs Sample Rate, 5MHz Sine OVDD Wave Input, –1dB 1.8V VDD ...
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... LTC2239 CTIO (Pin 1): Positive Differential Analog Input (Pin 2): Negative Differential Analog Input. IN REFH (Pins 3, 4): ADC High Reference. Short together and bypass to pins 5, 6 with a 0.1µF ceramic chip capacitor as close to the pin as possible. Also bypass to pins 5, 6 with an additional 2.2µ ...
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... INTERNAL CLOCK SIGNALS DIFF CLOCK/DUTY REF CYCLE AMP CONTROL REFH 0.1µF REFL CLK 2.2µF 1µF 1µF Figure 1. Functional Block Diagram LTC2239 FIFTH PIPELINED SIXTH PIPELINED ADC STAGE ADC STAGE SHIFT REGISTER AND CORRECTION CONTROL OUTPUT LOGIC DRIVERS 2239 F01 OGND SHDN MODE ...
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... LTC2239 DIAGRA t AP ANALOG N INPUT t H CLK – 5 D0-D9 – – – – 2239 TD01 2239fa ...
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... Aperture Delay Jitter The variation in the aperture delay time from conversion to conversion. This random variation will result in noise when sampling an AC input. The signal to noise ratio due to the jitter alone will be: SNR JITTER LTC2239 = –20log (2π • f • JITTER 2239fa ...
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... U U APPLICATIO S I FOR ATIO CONVERTER OPERATION As shown in Figure 1, the LTC2239 is a CMOS pipelined multistep converter. The converter has six pipelined ADC stages; a sampled analog input will result in a digitized value five cycles later (see the Timing Diagram section). For optimal AC performance the analog inputs should be driven differentially ...
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... Poor matching will result in higher even order harmonics, especially the second Input Drive Circuits Figure 3 shows the LTC2239 being driven transformer with a center tapped secondary. The second- ary center tap is DC biased with V + signal at its optimum DC level. Terminating on the trans- IN – ...
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... Figure 8, the series inductors are impedance matching elements that maximize the ADC bandwidth. Reference Operation Figure 9 shows the LTC2239 reference circuitry consisting of a 1.5V 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 (± ...
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... A sinusoidal clock can also be used along with a low-jitter squaring circuit before the CLK pin (see Figure 11). The noise performance of the LTC2239 can depend on the clock signal quality as much as on the analog input. Any noise present on the clock signal will result in additional aperture jitter that will be RMS summed with the inherent ADC aperture jitter ...
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... PLL to lock onto the input clock. To use the clock duty cycle stabilizer, the MODE pin should be connected to 1/3V The lower limit of the LTC2239 sample rate is determined by droop of the sample-and-hold circuits. The pipelined architecture of this ADC relies on storing analog signals on small valued capacitors ...
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... Data Format 11 1111 1110 Using the MODE pin, the LTC2239 parallel digital output 10 0000 0001 can be selected for offset binary or 2’s complement 10 0000 0000 10 0000 0000 format. Connecting MODE to GND or 1/3V binary output format ...
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... Heat Transfer Most of the heat generated by the LTC2239 is transferred from the die through the bottom-side exposed pad and package leads onto the printed circuit board. For good and OE electrical and thermal performance, the exposed pad DD should be soldered to a large grounded pad on the PC board ...
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... PCBs. The differential pairs must be close together, and dis- tanced from other signals. The differential pair should be guarded on both sides with copper distanced at least 3x the distance between the traces, and grounded with vias no more than 1/4 inch apart. LTC2239 2239fa 19 ...
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... LTC2239 U U APPLICATIO S I FOR ATIO 2239fa ...
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... U U APPLICATIO S I FOR ATIO Silkscreen Top W U Inner Layer 2 GND LTC2239 Topside 2239fa 21 ...
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... LTC2239 U U APPLICATIO S I FOR ATIO Inner Layer 3 Power Silkscreen Bottom Bottomside 2239fa ...
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... DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.20mm 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 LTC2239 BOTTOM VIEW—EXPOSED PAD 0.23 TYP R = 0.115 (4 SIDES) ...
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