LTC1569-7 Linear Phase, DC Accurate, Tunable, 10th Order Lowpass Filter Furthermore, its root raised cosine response offers the FEATURES optimum pulse shaping for PAM data communications. n One External R Sets Cutoff Frequency The filter attenuation is 57dB at 1.5 f , 60dB at 2 CUTOFF n Root Raised Cosine Response f , and in excess of 80dB at 6 f . DC-accuracy- CUTOFF CUTOFF n Up to 300kHz Cutoff on a Single 5V Supply sensitive applications benefit from the 5mV maximum DC n Up to 150kHz Cutoff on a Single 3V Supply offset. n 10th Order, Linear Phase Filter in an SO-8 The LTC1569-7 is the first sampled data filter which does n DC Accurate, V = 5mV OS(MAX) not require an external clock yet its cutoff frequency can be n Low Power Modes set with a single external resistor with a typical accuracy n Differential or Single-Ended Inputs of 3.5% or better. The external resistor programs an n 80dB CMRR (DC) internal oscillator whose frequency is divided by either 1, n 80dB Signal-to-Noise Ratio, V = 5V S 4 or 16 prior to being applied to the filter network. Pin 5 n Operates from 3V to 5V Supplies determines the divider setting. Thus, up to three cutoff U frequencies can be obtained for each external resistor APPLICATIO S value. Using various resistor values and divider settings, n Data Communication Filters for 3V Operation the cutoff frequency can be programmed over a range of n Linear Phase and Phase Matched Filters for I/Q seven octaves. Alternatively, the cutoff frequency can be Signal Processing set with an external clock and the clock-to-cutoff fre- n Pin Programmable Cutoff Frequency Lowpass Filters quency ratio is 32:1. The ratio of the internal sampling rate to the filter cutoff frequency is 64:1. DESCRIPTIO The LTC1569-7 is fully tested for a cutoff frequency of The LTC 1569-7 is a 10th order lowpass filter featuring 256kHz/128kHz with single 5V/3V supply although up to linear phase and a root raised cosine amplitude response. 300kHz cutoff frequencies can be obtained. The high selectivity of the LTC1569-7 combined with its The LTC1569-7 features power savings modes and it is linear phase in the passband makes it suitable for filtering available in an SO-8 surface mount package. both in data communications and data acquisition sytems. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATION Frequency Response, f = 128kHz/32kHz/8kHz CUTOFF Single 3V Supply, 128kHz/32kHz/8kHz Lowpass Filter 0 18 + V IN OUT V IN OUT 20 R = 10k EXT 3V 27 + IN V 3V 40 1F 3.48k LTC1569-7 36 GND R X 60 3V 2k 1F 1/16 1/4 45 V DIV/CLK 80 100pF 1/1 EASY TO SET f : CUTOFF 100 128kHz (10k/R ) EXT 1 10 100 1000 f = CUTOFF 1569-7 TA01 1, 4 OR 16 FREQUENCY (kHz) 1569-7 TA01a 1 GAIN (dB) U ULTC1569-7 O / ABS LUTEXAI U RATI GS PACKAGE ORDER I FOR ATIO (Note 1) Total Supply Voltage ................................................ 11V ORDER PART TOP VIEW NUMBER Power Dissipation.............................................. 500mW + IN 1 8 OUT Operating Temperature + LTC1569CS8-7 IN 2 7 V LTC1569C ............................................... 0 C to 70 C LTC1569IS8-7 GND 3 6 R X LTC1569I............................................ 40 C to 85 C V 4 5 DIV/CLK Storage Temperature ............................ 65 C to 150 C S8 PART S8 PACKAGE Lead Temperature (Soldering, 10 sec).................. 300 C MARKING 8-LEAD PLASTIC SO T = 125 C, q = 80 C/W (Note 6) JMAX JA 15697 1569I7 Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. A + V = 3V (V = 3V, V = 0V), f = 128kHz, R = 10k unless otherwise specified. S CUTOFF LOAD PARAMETER CONDITIONS MIN TYP MAX UNITS Filter Gain V = 5V, f = 8.192MHz, f = 5120Hz = 0.02 f l 0.10 0.00 0.10 dB S CLK IN CUTOFF f = 256kHz, V = 2.5V,f = 51.2kHz = 0.2 f l 0.25 0.15 0.05 dB CUTOFF IN P-P IN CUTOFF R = 5k, Pin 5 Shorted to Pin 4 f = 128kHz = 0.5 f l 0.50 0.41 0.25 dB EXT IN CUTOFF f = 204.8kHz = 0.8 f l 1.1 0.65 0.40 dB IN CUTOFF f = 256kHz = f , LTC1569C l 5.7 3.8 2.3 dB IN CUTOFF f = 256kHz = f , LTC1569I l 6.2 3.8 2.0 dB IN CUTOFF f = 384kHz = 1.5 f l 58 48 dB IN CUTOFF f = 512kHz = 2 f l 62 54 dB IN CUTOFF f = 768kHz = 3 f l 67 64 dB IN CUTOFF V = 2.7V, f = 1MHz, f = 625Hz = 0.02 f l 0.08 0.00 0.12 dB S CLK IN CUTOFF f = 31.25kHz, V = 1V,f = 6.25kHz = 0.2 f l 0.25 0.15 0.05 dB CUTOFF IN P-P IN CUTOFF Pin 6 Shorted to Pin 4, External Clock f = 15.625kHz = 0.5 f l 0.50 0.40 0.30 dB IN CUTOFF f = 25kHz = 0.8 f l 0.75 0.65 0.50 dB IN CUTOFF f = 31.25kHz = f l 3.3 3.15 3.0 dB IN CUTOFF f = 46.875kHz = 1.5 f l 57 52 dB IN CUTOFF f = 62.5kHz = 2 f l 60 54 dB IN CUTOFF f = 93.75kHz = 3 f l 66 58 dB IN CUTOFF Filter Phase V = 2.7V, f = 4MHz, f = 2500Hz = 0.02 f 11 Deg S CLK IN CUTOFF = 125kHz, Pin 6 Shorted to f = 25kHz = 0.2 f l 114 112 110 Deg f CUTOFF IN CUTOFF Pin 4, External Clock f = 62.5kHz = 0.5 f l 78 80 82 Deg IN CUTOFF f = 100kHz = 0.8 f l 85 83 81 Deg IN CUTOFF = 125kHz = f l 155 158 161 Deg f IN CUTOFF f = 187.5kHz = 1.5 f 95 Deg IN CUTOFF Filter Cutoff Accuracy R = 10.24k from Pin 6 to Pin 7, 125kHz 1% EXT when Self-Clocked V = 3V, Pin 5 Shorted to Pin 4 S Filter Output DC Swing V = 3V, Pin 3 = 1.11V 2.1 V S P-P l 1.9 V P-P V = 5V, Pin 3 = 2V 3.9 V S P-P l 3.7 V P-P V = 5V 8.6 V S P-P LTC1569C l 8.4 V P-P LTC1569I l 8.0 V P-P 2 U WU U W W W