LTC1569-6 Linear Phase, DC Accurate, Low Power, 10th Order Lowpass Filter tems. Furthermore, its root raised cosine response offers FEATURES the optimum pulse shaping for PAM data communica- n One External R Sets Cutoff Frequency tions. The filter attenuation is 50dB at 1.5 f , 60dB CUTOFF n Root Raised Cosine Response at 2 f , and in excess of 80dB at 6 f . DC- CUTOFF CUTOFF n 3mA Supply Current with a Single 3V Supply accuracy-sensitive applications benefit from the 5mV n Up to 64kHz Cutoff on a Single 3V Supply maximum DC offset. n 10th Order, Linear Phase Filter in an SO-8 The LTC1569-6 sampled data filter does not require an n DC Accurate, V = 5mV OS(MAX) external clock yet its cutoff frequency can be set with a n Low Power Modes single external resistor with a typical accuracy of 3.5% or n Differential or Single-Ended Inputs better. The external resistor programs an internal oscilla- n 80dB CMRR (DC) tor whose frequency is divided by either 1, 4 or 16 prior to n 82dB Signal-to-Noise Ratio, V = 5V S being applied to the filter network. Pin 5 determines the n Operates from 3V to 5V Supplies divider setting. Thus, up to three cutoff frequencies can be U obtained for each external resistor value. Using various APPLICATIO S resistor values and divider settings, the cutoff frequency n Data Communication Filters for 3V Operation can be programmed over a range of six octaves. Alterna- n Linear Phase and Phase Matched Filters for I/Q tively, the cutoff frequency can be set with an external Signal Processing clock and the clock-to-cutoff frequency ratio is 64:1. The n Pin Programmable Cutoff Frequency Lowpass Filters ratio of the internal sampling rate to the filter cutoff frequency is 128:1. DESCRIPTIO The LTC1569-6 is fully tested for a cutoff frequency of The LTC 1569-6 is a 10th order lowpass filter featuring 64kHz with a single 3V supply. linear phase and a root raised cosine amplitude response. The LTC1569-6 features power saving modes and it is The high selectivity of the LTC1569-6 combined with its available in an SO-8 surface mount package. linear phase in the passband makes it suitable for filtering , LTC and LT are registered trademarks of Linear Technology Corporation. both in data communications and data acquisition sys- TYPICAL APPLICATIO Frequency Response, f = 64kHz/16kHz/4kHz CUTOFF 0 Single 3V Supply, 64kHz/16kHz/4kHz Lowpass Filter 20 18 + V IN OUT V IN OUT R = 10k 3V EXT 27 + 40 IN V 3V 1F 3.48k LTC1569-6 36 GND R X 60 3V 1F 1/16 2k 1/4 45 V DIV/CLK 80 100pF 1/1 EASY TO SET f : CUTOFF 100 64kHz (10k/R ) EXT 1 10 100 1000 f = CUTOFF 1569-6 TA01 1, 4 OR 16 FREQUENCY (kHz) 1569-6 TA01a 1 GAIN (dB) U ULTC1569-6 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 + LTC1569CS8-6 IN 2 7 V LTC1569C ............................................... 0 C to 70 C LTC1569IS8-6 GND R 3 6 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 = 150 C/W JMAX JA 15696 1569I6 Consult factory for Military grade parts. LECTR AL CHARACTERIST E IC ICS 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 = 64kHz, R = 10k unless otherwise specified. S CUTOFF LOAD PARAMETER CONDITIONS MIN TYP MAX UNITS Filter Gain V = 5V, f = 4.096MHz, f = 1280Hz = 0.02 f l 0.05 0.05 0.15 dB S CLK IN CUTOFF f = 64kHz, V = 1.4V ,f = 12.8kHz = 0.2 f l 0.25 0.15 0.05 dB CUTOFF IN P-P IN CUTOFF R = 10k, Pin 5 Shorted f = 32kHz = 0.5 f l 0.65 0.55 0.4 dB EXT IN CUTOFF to Pin 4 f = 51.2kHz = 0.8 f l 1.3 1.0 0.7 dB IN CUTOFF f = 64kHz = f l 5.3 3.8 2.4 dB IN CUTOFF f = 97.5kHz = 1.5 f (LTC1569I) l 60 40 dB IN CUTOFF f = 97.5kHz = 1.5 f (LTC1569C) l 60 48 dB IN CUTOFF f = 128kHz = 2 f l 62 50 dB IN CUTOFF f = 192kHz = 3 f l 71 60 dB IN CUTOFF V = 2.7V, f = 1MHz, f = 312Hz = 0.02 f l 0.12 0.05 0.16 dB S CLK IN CUTOFF f = 15.625kHz, f = 3125kHz = 0.2 f l 0.25 0.15 0.05 dB CUTOFF IN CUTOFF = 1V , Pin 6 Shorted f = 7812kHz = 0.5 f l 0.65 0.55 0.4 dB V IN P-P IN CUTOFF to Pin 4, External Clock f = 12.5kHz = 0.8 f l 1.1 0.9 0.7 dB IN CUTOFF f = 15.625kHz = f l 3.6 3.4 3.2 dB IN CUTOFF = 23.44kHz = 1.5 f (LTC1569I) l 54 48 dB f IN CUTOFF f = 23.44kHz = 1.5 f (LTC1569C) l 54 50 dB IN CUTOFF f = 31.25kHz = 2 f (LTC1569I) l 60 52 dB IN CUTOFF = 31.25kHz = 2 f (LTC1569C) l 60 55 dB f IN CUTOFF f = 46.88kHz = 3 f l 66 60 dB IN CUTOFF Filter Phase V = 2.7V, f = 4MHz, f = 1250Hz = 0.02 f 11 Deg S CLK IN CUTOFF f = 62.5kHz, Pin 6 f = 12.5kHz = 0.2 f l 114 111 108 Deg CUTOFF IN CUTOFF Shorted to Pin 4, f = 31.25kHz = 0.5 f l 79 82 85 Deg IN CUTOFF External Clock f = 50kHz = 0.8 f l 83 79 75 Deg IN CUTOFF f = 62.5kHz = f l 156 162 168 Deg IN CUTOFF f = 93.75kHz = 1.5 f 91 Deg IN CUTOFF Filter Cutoff Accuracy R = 10.24k from Pin 6 to Pin 7, 62.5kHz 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 (Note 6) 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, Pin 5 Shorted to Pin 7, R = 20k 8.5 V S LOAD P-P 2 U WU U W W W