MAX7480 19-1416 Rev 0 1/99 8th-Order, Lowpass, Butterworth, Switched-Capacitor Filter General Description Features The MAX7480 8th-order, lowpass, Butterworth, 8th-Order, Lowpass Butterworth Filter switched-capacitor filter (SCF) operates from a single Low Noise and Distortion: -73dB THD + Noise +5V supply. The device draws only 2.9mA of supply current and allows corner frequencies from 1Hz to Clock-Tunable Corner Frequency (1Hz to 2kHz) 2kHz, making it ideal for low-power post-DAC filtering 100:1 Clock-to-Corner Ratio and anti-aliasing applications. The MAX7480 features a shutdown mode, which reduces the supply current to +5V Single-Supply Operation 0.2A. Low Power Two clocking options are available: self-clocking 2.9mA (Operating Mode) (through the use of an external capacitor) or external 0.2A (Shutdown Mode) clocking for tighter corner-frequency control. An offset adjust pin allows for adjustment of the DC output level. Available in 8-Pin SO/DIP Package The MAX7480 Butterworth filter provides a maximally Low Output Offset: 5mV flat passband response. The fixed response simplifies the design task to selecting a clock frequency. Ordering Information Applications ADC Anti-Aliasing PART TEMP. RANGE PIN-PACKAGE MAX7480ESA -40C to +85C 8 SO Post-DAC Filtering MAX7480EPA -40C to +85C 8 Plastic DIP Pin Configuration Typical Operating Circuit TOP VIEW V SUPPLY COM 1 8 CLK 0.1F V DD IN 2 7 SHDN SHDN MAX7480 GND 3 6 OS INPUT IN OUT OUTPUT V 4 5 OUT MAX7480 DD SO/DIP CLOCK CLK COM OS 0.1F GND Maxim Integrated Products 1 For free samples & the latest literature: 8th-Order, Lowpass, Butterworth, Switched-Capacitor Filter ABSOLUTE MAXIMUM RATINGS V to GND..............................................................-0.3V to +6V Operating Temperature Range ...........................-40C to +85C DD IN, OUT, COM, OS, CLK ............................-0.3V to (V + 0.3V) Storage Temperature Range .............................-65C to +150C DD SHDN........................................................................-0.3V to +6V Lead Temperature (soldering, 10sec) .............................+300C OUT Short-Circuit Duration...................................................1sec Continuous Power Dissipation (T = +70C) A 8-Pin SO (derate 5.88mW/C above +70C)................471mW 8-Pin DIP (derate 9.09mW/C above +70C)...............727mW 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 CHARACTERISTICS (V = +5V, filter output measured at OUT, 10k 50pF load to GND at OUT, OS = COM, 0.1F from COM to GND, SHDN = DD V , f = 100kHz, T = T to T , unless otherwise noted. Typical values are at T = +25C.) DD CLK A MIN MAX A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS FILTER CHARACTERISTICS Corner Frequency f (Note 1) 0.001 to 2 kHz C Clock-to-Corner Ratio f /f 100:1 CLK C Clock-to-Corner Tempco 10 ppm/C Output Voltage Range 0.25 V - 0.25 V DD Output Offset Voltage V V = V = V / 2 5 25 mV OFFSET IN COM DD DC Insertion Gain with V = V / 2 (Note 2) -0.1 0.15 0.3 dB COM DD Output Offset Removed Total Harmonic Distortion f = 200Hz, V = 4Vp-p, IN IN THD+N -73 dB plus Noise measurement bandwidth = 22kHz OS Voltage Gain to OUT A 1 V/V OS Input Voltage Range at OS V V 0.1 V OS COM V / 2 V / 2 V / 2 DD DD DD Input, COM externally driven - 0.5 + 0.5 COM Voltage Range V V COM V / 2 V / 2 V / 2 DD DD DD Output, COM internally biased - 0.2 + 0.2 Input Resistance at COM R 75 125 k COM Clock Feedthrough 10 mVp-p Resistive Output Load Drive R 10 1 k L Maximum Capacitive Load at C 50 500 pF L OUT Input Leakage Current at COM SHDN = GND, V = 0 to V 0.1 10 A COM DD Input Leakage Current at OS V = 0 to (V - 1V) (Note 3) 0.1 10 A OS DD CLOCK Internal Oscillator Frequency f C = 1000pF (Note 4) 40 53 67 kHz OSC OSC Clock Input Current I V = 0 or 5V 24 40 A CLK CLK Clock Input High V V - 0.5 V IH DD Clock Input Low V 0.5 V IL 2 MAX7480