ltc1569-7 Linear Technology Corporation, ltc1569-7 Datasheet
ltc1569-7
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ltc1569-7 Summary of contents
Page 1
... The ratio of the internal sampling rate to the filter cutoff frequency is 64:1. The LTC1569-7 is fully tested for a cutoff frequency of 256kHz/128kHz with single 5V/3V supply although up to 300kHz cutoff frequencies can be obtained. The LTC1569-7 features power savings modes and it is available in an SO-8 surface mount package ...
Page 2
... LTC1569 BSOLUTE (Note 1) Total Supply Voltage ................................................ 11V Power Dissipation .............................................. 500mW Operating Temperature LTC1569C ............................................... LTC1569I ............................................ – Storage Temperature ............................ – 150 C Lead Temperature (Soldering, 10 sec).................. 300 C ELECTRICAL C HARA TERISTICS C The denotes the specifications which apply over the full operating temperature range, otherwise specifications are – ...
Page 3
... Note 5: The minimum clock frequency is arbitrarily defined as the frequecy at which the filter DC offset changes by more than 5mV. Note 6: Thermal resistance varies depending upon the amount of PC board metal attached to the device. covered with 2oz copper on both sides. LTC1569 MIN TYP ...
Page 4
... LTC1569 TYPICAL PERFOR A CE CHARACTERISTICS Gain vs Frequency 10 – 100 FREQUENCY (kHz) THD vs Input Frequency –68 – PIN –72 – 1. 128kHz CUTOFF + – OUT R = 10k EXT – PIN – INPUT FREQUENCY (kHz) ...
Page 5
... ORDER LINEAR PHASE FILTER NETWORK – POWER GND 3 6 CONTROL DIVIDER/ – BUFFER PRECISION OSCILLATOR LTC1569-7 – (Pin 4). The internal divider – is recommended). The internal divider is set + (Pin 7). In the X pin OUT + V R EXT R X DIV/CLK 1569-7 BD shorted X – ...
Page 6
... Figure 1, the divider is controlled by the DIV/CLK (Pin 5). Table 1 summarizes the cutoff frequency vs external resistor values for the divide-by-1 mode. In the divide-by-4 and divide-by-16 modes, the cutoff frequencies in Table 1 will be lowered by 4 and 16 respectively. When the LTC1569 the divide-by-4 and divide-by-16 modes the power is automatically ...
Page 7
... The cutoff frequency is easily estimated from the equation in Figure 1. Examples 1 and 2 illustrate how to use the graphs in Figures 2 through 7 to get a more precise estimate of the cutoff frequency. Example 1: LTC1569- 20k, V EXT mode, DIV/CLK (Pin 5) connected to V Using the equation in Figure 1, the approximate filter cutoff frequency 128kHz • ...
Page 8
... Refer to the Typical Performance Characteristics section (Pin estimate the THD for a given input level. Dynamic Input Impedance The unique input sampling structure of the LTC1569-7 has – a dynamic input impedance which depends on the con- + 50mV) figuration, i.e., differential or single-ended, and the clock frequency ...
Page 9
... V RMS 145 V RMS DC Offset The output DC offset of the LTC1569-7 is trimmed to less than 5mV. The trimming is performed with V –1.1V with the filter cutoff frequency set to 8kHz (R 10k, DIV/CLK shorted to V performance, appropriate PC layout techniques should be used. The filter IC should be soldered to the PC board. The ...
Page 10
... Input signals with frequencies near 2 • will be aliased to the passband of the filter and CUTOFF appear at the output unattenuated. Power Supply Current The power supply current depends on the operating mode. When the LTC1569 the divide-by-1 mode, or when U TYPICAL APPLICATIO S Single 3V Operation, AC Coupled Input, 128kHz Cutoff Frequency 0 ...
Page 11
... TYP 0.014 – 0.019 (0.355 – 0.483) LTC1569-7 128kHz Cutoff Frequency OUT V IN OUT R = 10k EXT 2 7 – LTC1569 GND – V DIV/CLK 128kHz 10k f = CUTOFF EXT FOR PIN GROUND, OPEN, V 0.189 – ...
Page 12
... CLK CUTOFF f CUTOFF(MAX) f CUTOFF(MAX) +3V 20k OUT V OUT R 10k +3V EXT 2 7 – LTC1569-7 3.48k 3 6 GND 20k 4 5 – V DIV/CLK 4-Level, 400kbps (200ksps) Eye Diagram 1 s/DIV 1569-7 TA08 = 75/1 or 150/1, Very Low Noise = 50/1 or 100/ 100kHz CUTOFF(MAX) = 25/1, 50/1, 100/1 or 200/ 200kHz ...