DEMO MANUAL DC393 LTC1564 FILTER BOARD Evaluation Board for LTC1564 Digitally Controlled Antialiasing Filter and 4-Bit P.G.A. DESCRIPTIO This demonstration circuit allows the user to evaluate the Some key features of this demo circuit include: LTC 1564 digitally controlled antialiasing filter. The cutoff 4-bit digitally controlled 8th order lowpass filter frequency (f ) and passband gain are fully programmable C f = 10kHz to 150kHz in 10kHz steps while the shape of the lowpass response is fixed. A C latching digital interface stores f and gain settings or it C 4-bit digitally controlled programmable gain amplifier can be bypassed for control directly from the pins through G = 1 to 16 in 1V/V steps either the on-board toggle switches or using the optional connector to control the pins externally. The LTC1564 100dB attenuation at 2.5 f C operates from 2.7V to 10V total supply voltage (single or Rail-to-rail input and output range split supplies) and comes in a 16 pin surface mount SSOP. This board demonstrates proper layout, bypassing and Miniature 16-Pin SSOP package optional buffering to achieve best performance. Applica- tions include DSP antialiasing and reconstruction filtering, communications and instruments with high dynamic range, , LTC and LT are registered trademarks of Linear Technology Corporation. up to 20 bits, and sampling rates to 300+ kilosamples per second. TYPICAL PERFOR A CE CHARACTERISTICS A D BOARD PHOTO Demo Circuit Frequency Response 40 20 0 20 40 60 D B 80 C 100 A 120 140 0.1 110 f /f IN C 393A TA01 A: f = 10kHz, GAIN = 1, V = 1V C IN RMS B: f = 10kHz, GAIN = 16, V = 62.5mV C IN RMS C: f = 150kHz, GAIN = 1, V = 1V C IN RMS D: f = 150kHz, GAIN = 16, V = 62.5mV C IN RMS dc393f 1 GAIN (dB) UWU UDEMO MANUAL DC393 LTC1564 FILTER BOARD PACKAGE A D SCHE ATIC DIAGRA + dc393f 2 SGND EN CS RST LOGIC 0 AGND 65 4 AGND 0 OPOUT SW3 R14 1 J2 J1 OPT 1 OPOUT UP 2 1 OPOUT 2 1 OPT 4 3 123 C11 4 3 6 5 OPT 54 32 6 5 8 7 CS RST 8 7 10 9 10 9 12 11 12 11 14 13 14 13 16 15 16 15 18 17 + ENABLE OPV 18 17 R27 20 19 2 20 19 10k 1 3 22 21 C9 OPT 3528 22 21 24 23 + JP1 24 23 OPV R13 R12 LOGIC 0 10k 10k U1 TBD C1 0.1F OPT 3 7 LOGIC 0 R1 SGND C12 + OPT OPT 2 LOGIC 1 LOGIC 1 LOGIC 1 4 + OUT R2 C2 0.1F OPT V IN OPT 1 OUT OPV J3 IN 1 J4 OUT C6 C10 OPT 3528 IN R3 LTC1564CG U2 1F R26 54 32 0 OPV 1 16 2 3 4 5 OPT OUT IN C3 C5 2 15 V AGND 0.1F OPT C4 R15 220 3 14 + 0.1F EN V R8 R9 R10 R11 LOGIC 1 V 1 0 1 0 R16 220 4 13 R21 220 RST 10k 10k 10k 10k R4 R5 R6 R7 LOGIC 1 SW2 CS/HOLD RST SW1 10k 10k 10k 10k 1 12 R17 220 5 12 R22 220 1 12 F3 G3 F3 G3 F2 R18 220 6 11 R23 220 G2 11 11 F2 G2 F1 R19 220 7 10 R24 220 G1 2 2 F1 G1 R20 220 8 9 R25 220 F0 G0 3 10 3 10 F0 G0 4 9 4 9 F0 F1 F2 F3 G3 G2 G1 G0 8 8 5 5 LTC1564 6 7 6 7 TOP VIEW UP UP + OUT 1 16 IN V JP4 V 2 15 AGND 1 2 + V LOGIC 1 + LOGIC 0 EN 3 14 V C8 LOGIC 0 10F LOGIC 1 CS/HOLD 4 13 RST SGND SGND 16V F3 5 12 G3 JP3 3 1 V AGND F2 6 11 G2 C7 2 SINGLE DUAL 10F F1 7 10 G1 V SUPPLY SUPPLY 16V 393 Schem1 F0 8 9 G0 JP2 1 3 G PACKAGE 2 16-LEAD PLASTIC SSOP LOGIC 0 V RETURN LOGIC 0 NOTES: UNLESS OTHERWISE SPECIFIED 1. ALL RESISTORS ARE IN OHMS, 0805 ALL CAPACITORS ARE IN MICROFARADS, 0805 2. SWITCHES ARE SHOWN WITH ROCKER IN UP POSITION, GIVING A LOGIC 1 STATE LOGIC 0 + W WU