MAX7490/MAX7491 19-1768 Rev 1 4/09 Dual Universal Switched-Capacitor Filters General Description Features The MAX7490/MAX7491 consist of two identical low- Dual 2nd-Order Filter in a 16-Pin QSOP Package power, low-voltage, wide dynamic range, rail-to-rail, High Accuracy 2nd-order switched-capacitor building blocks. Each of Q Accuracy: 0.2% the two filter sections, together with two to four external Clock-to-Center Frequency Error: 0.2% resistors, can generate all standard 2nd-order func- tions: bandpass, lowpass, highpass, and notch (band Rail-to-Rail Input and Output Operation reject). Three of these functions are simultaneously Single-Supply Operation: +5V (MAX7490) available. Fourth-order filters can be obtained by cas- cading the two 2nd-order filter sections. Similarly, high- or +3V (MAX7491) er order filters can easily be created by cascading Internal or External Clock multiple MAX7490/MAX7491s. Highpass, Lowpass, Bandpass, and Notch Filters Two clocking options are available: self-clocking (through the use of an external capacitor) or external Clock-to-Center Frequency Ratio of 100:1 clocking for tighter cutoff frequency control. The clock- Internal Sampling-to-Center Frequency Ratio to-center frequency ratio is 100:1. Sampling is done at of 200:1 twice the clock frequency, further separating the cutoff frequency and Nyquist frequency. Center Frequency up to 40kHz The MAX7490/MAX7491 have an internal rail splitter Easily Cascaded for Multipole Filters that establishes a precise common voltage needed for Low-Power Shutdown: < 1A Supply Current single-supply operation. The MAX7490 operates from a single +5V supply and the MAX7491 operates from a single +3V supply. Both devices feature a low-power shutdown mode and come in a 16-pin QSOP package. Ordering Information SUPPLY Applications PIN- PART TEMP RANGE VOLTAGE Tunable Active Filters PACKAGE (+V) Multipole Filters MAX7490CEE+ 0C to +70C 16 QSOP 5 ADC Anti-Aliasing MAX7490EEE+ -40C to +85C 16 QSOP 5 Post-DAC Filtering MAX7491CEE+ 0C to +70C 16 QSOP 3 Adaptive Filtering MAX7491EEE+ -40C to +85C 16 QSOP 3 +Denotes a lead(Pb)-free/RoHS-compliant package. Phase-Locked Loops (PLLs) Set-Top Boxes Pin Configuration TOP VIEW + LPA 1 16 LPB BPA 2 15 BPB NA/HPA 14 NB/HPB 3 Typical Application Circuit appears at end of data sheet. INVA 4 MAX7490 13 INVB MAX7491 SA 5 12 SB SHDN 6 11 COM GND 7 10 EXTCLK V 8 9 CLK DD QSOP Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.Dual Universal Switched-Capacitor Filters ABSOLUTE MAXIMUM RATINGS V to GND..............................................................-0.3V to +6V Operating Temperature Range DD EXTCLK, SHDN to GND ...........................................-0.3V to +6V MAX749 CEE .....................................................0C to +70C INV , LP , BP , N /HP , S , COM, MAX749 EEE...................................................-40C to +85C CLK to GND............................................-0.3V to (V + 0.3V) Die Temperature ..............................................................+150C DD Maximum Current into Any Pin ...........................................50mA Storage Temperature.........................................-65C to +150C Continuous Power Dissipation (T = +70C) Lead Temperature (soldering, 10s) .................................+300C A 16-Pin QSOP (derate 8.30mW/C above +70C).........667mW Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICSMAX7490 (V = V = +5V f = 625kHz 10k 50pF load to V /2 at LP , BP , and N /HP V = V 0.1F from COM to DD EXTCLK CLK DD SHDN DD GND 50% duty-cycle clock input COM = V /2 T = T to T . Typical values are at T = +25C, unless otherwise noted.) DD A MIN MAX A (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS FILTER 0.001 to Center Frequency Range f Mode 1 kHz O 40 Clock-to-Center Frequency Mode 1, R1 = R3 = 50k , R2 = 10k, f /f 0.2 0.7 % CLK O Accuracy Q = 5, deviation from 100:1 Q Accuracy M od e 1, R1 = R3 = 50 k, R2 = 10k, Q = 5 0.2 2% f Temperature Coefficient 1 ppm/C O Q Temperature Coefficient 5 ppm/C DC Lowpass Gain Accuracy Mode 1, R1 = R2 = 10k0.1 0.5 % V DC offset of input inverter 3 12.5 OS1 DC Offset Voltage (Figure 8) V DC offset of 1st integrator 4 15 mV OS2 V DC offset of 2nd integrator 4 30 OS3 Crosstalk (Note 2) f = 10kHz -60 dB IN V /2 V /2 DD DD Input: COM externally driven V /2 DD - 0.5 + 0.5 COM Voltage Range V V COM V /2 V /2 DD DD Output: COM internally driven V /2 DD - 0.2 + 0.2 Input Resistance at COM R 140 250 325 k COM Clock Feedthrough Up to 5th harmonic of f 200 V CLK RMS Mode 1, R1 = R2 = R3 =10k, LP output, Noise (Note 3) 60 V RMS Q = 1 Output Voltage Swing 0.2 V - 0.2 V D D Input Leakage Current at COM SHDN = GND, V = 0 to V 0.1 10 A COM DD CLOCK Maximum Clock Frequency f 4 MHz CLK EXTCLK = GND, C = 1000pF 95 135 175 kHz Internal Oscillator Frequency OSC f OSC (Note 4) EXTCLK = GND, C = 100pF 1.35 MHz OSC Clock Input High V - 0.5 V DD 2 MAX7490/MAX7491