MAX7418MAX7425 19-1821 Rev 0 11/00 5th-Order, Lowpass, Switched-Capacitor Filters General Description Features The MAX7418MAX7425 5th-order, low-pass, switched- 5th-Order, Lowpass Filters capacitor filters (SCFs) operate from a single +5V Elliptic Response (MAX7418/MAX7421/ (MAX7418MAX7421) or +3V (MAX7422MAX7425) MAX7422/MAX7425) supply. These devices draw only 3mA of supply current Bessel Response (MAX7419/MAX7423) and allow corner frequencies from 1Hz to 45kHz, mak- Butterworth Response (MAX7420/MAX7424) ing them ideal for low-power post-DAC filtering and anti- aliasing applications. They feature a shutdown mode Clock-Turnable Corner Frequency (1Hz to 45kHz) that reduces supply current to 0.2A. Single-Supply Operation Two clocking options are available: self-clocking +5V (MAX7418MAX7421) (through the use of an external capacitor), or external +3V (MAX7422MAX7425) clocking for tighter corner-frequency control. An offset Low Power adjust pin allows for adjustment of the DC output level. 3mA (Operating Mode) The MAX7418/MAX7422 deliver 53dB of stopband 0.2A (Shutdown Mode) rejection and a sharp rolloff with a 1.6 transition ratio. The MAX7421/MAX7425 achieve a sharper rolloff with a Available in 8-Pin MAX Package 1.25 transition ratio while still providing 37dB of stop- Low Output Offset: 4mV band rejection. The MAX7419/MAX7423 Bessel filters provide low overshoot and fast settling, and the Ordering Information MAX7420/MAX7424 Butterworth filters provide a maxi- mally flat passband response. Their fixed response sim- PART TEMP. RANGE PIN-PACKAGE plifies the design task of selecting a clock frequency. MAX7418CUA 0C to +70C 8 MAX Applications MAX7418EUA -40C to +85C 8 MAX MAX7419CUA 0C to +70C 8 MAX ADC Anti-Aliasing CT2 Base Stations MAX7419EUA -40C to +85C 8 MAX DAC Postfiltering Speech Processing MAX7420CUA 0C to +70C 8 MAX MAX7420EUA -40C to +85C 8 MAX Selector Guide MAX7421CUA 0C to +70C 8 MAX OPERATING MAX7421EUA -40C to +85C 8 MAX PART FILTER RESPONSE VOLTAGE (V) Ordering Information continued at end of data sheet. MAX7418 r = 1.6 +5 MAX7419 Bessel +5 Typical Operating Circuit MAX7420 Butterworth +5 MAX7421 r = 1.25 +5 V SUPPLY Selector Guide continued at end of data sheet. 0.1F Pin Configuration V DD SHDN TOP VIEW INPUT IN OUT OUTPUT COM 1 8 CLK MAX7418 MAX7425 IN 2 7 SHDN MAX7418 CLOCK CLK COM MAX7425 GND 3 6 OS OS 0.1F GND V 4 5 OUT DD MAX Maxim Integrated Products 1 For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800. For small orders, phone 1-800-835-8769.5th-Order, Lowpass, Switched-Capacitor Filters ABSOLUTE MAXIMUM RATINGS V to GND..............................................................-0.3V to +6V Operating Temperature Ranges DD IN, OUT, COM, OS, CLK, SHDN ................-0.3V to (V + 0.3V) MAX74 C A ...................................................0C to +70C DD OUT Short-Circuit Duration.......................................................1s MAX74 E A ................................................-40C to +85C Continuous Power Dissipation (T = +70C) Junction Temperature......................................................+150C A 8-Pin MAX (derate 4.1mW/C above +70C) .............330mW Storage Temperature Range .............................-65C to +160C Lead Temperature (soldering, 10s) .................................+300C 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 CHARACTERISTICSMAX7418MAX7421 (V = +5V, filter output measured at OUT, 10k 50pF load to GND at OUT, OS = COM, 0.1F capacitor from COM to GND, DD SHDN = V , f = 2.2MHz, 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 CHARACTERISTICSFILTER CHARACTERISTICS Corner Frequency f V = 4Vp-p (Note 1) 0.001 to 30 kHz c IN 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 4 25 mV OFFSET IN COM DD MAX7418/MAX7421 0 0.2 0.4 DC Insertion Gain with V = V / 2 COM DD dB Output Offset Removed (Note 2) MAX7419/MAX7420 -0.2 0 +0.2 MAX7418 -76 f = 2KHz, IN MAX7419 -78 Total Harmonic Distortion V = 4Vp-p, IN THD+N dB plus Noise measurement MAX7420 -67 bandwidth = 80kHz MAX7421 -78 Offset Voltage Gain A OS to OUT 1 V/V OS Input, COM externally driven 2.0 2.5 3.0 COM Voltage Range V V COM Output, COM unconnected 2.3 2.5 2.7 Input Voltage Range at OS V Input, OS externally driven V 0.1 V OS COM Input Resistance at COM R 100 140 k COM Clock Feedthrough 5 mVp-p Resistive Output Load Drive R 10 1 k L Maximum Capacitive Output C 50 500 pF L Load Drive 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 0.1 10 A OS DD CLOCKCLOCK 68 87 106 MAX7418/MAX7421 C = 1000pF (Note OSC Internal Oscillator Frequency f kHz OSC 3) MAX7419/MAX7420 86 110 135 MAX7418/MAX7421 40 60 Clock Output Current I V = 0 or 5V A CLK CLK (Internal Oscillator Mode) MAX7419/MAX7420 50 75 Clock Input High V 4.5 V IH Clock Input Low V 0.5 V IL 2 MAX7418MAX7425