MAX270/MAX271 Digitally-Programmed, Dual 2nd-Order Continuous Lowpass Filter General Description Features S Continuous-Time Filtering - No Clock Required The MAX270/MAX271 are digitally-programmed, dual second-order continuous-time lowpass filters. Their typi- S Dual 2nd-Order Lowpass Filters cal dynamic range of 96dB surpasses most switched S Sections Independently Programmable: 1kHz to capacitor filters which require additional filtering to 25kHz remove clock noise. The MAX270/MAX271 are ideal for S 96dB Dynamic Range anti-aliasing and DAC smoothing applications and can S No External Components be cascaded for higher-order responses. S Cascadable for Higher Order The two filter sections are independently programmable S Low-Power Shutdown Mode by either microprocessor (FP) control or pin strapping. Cutoff frequencies in the 1kHz to 25kHz range can be S Track-and-Hold (MAX271) selected. Ordering Information The MAX270 has an on-board, uncommitted op amp, while the MAX271 has an internal track-and-hold (T/H). PART TEMP RANGE PIN-PACKAGE MAX270CPP 0NC to +70NC 20 PDIP Applications MAX270CWP 0NC to +70NC 20 Wide SO Lowpass Filtering MAX270EPP -40NC to +85NC 20 PDIP Anti-Aliasing Filter MAX270EWP -40NC to +85NC 20 Wide SO Output Smoothing MAX271CNG 0NC to +70NC 20 PDIP Low-Noise Applications MAX271CWG 0NC to +70NC 20 Wide SO Anti-Aliasing and Track-and-Hold (MAX271) MAX271ENG -40NC to +85NC 20 PDIP MAX271EWG -40NC to +85NC 20 Wide SO Devices are available in a lead(Pb)-free/RoHS-compliant package. Specify lead-free by adding a plus (+) to the part number when ordering. Pin Configurations Typical Operating Circuit TOP VIEW +5V -5V 1 OP OUT OP IN 20 V+ GND V- 2 V+ D6 19 IN INA OUTA A/D WITH FILTER A T/H 3 OUTA D5 18 ANTI-ALIASING 4 SHDN D4 17 MAX270 MAX270 DSB 5 INA D3 16 OUT OUTB INB 6 V- D2 15 FILTER B DAC 7 INB D1 14 ANTI-ALIASING 8 OUTB D0 13 AO D0-D6 CS WR 91GND A0 2 Pin Configurations continued at end 10 WR CS 11 of data sheet. P OR PIN-STRAP CONTROL PDIP/SO(W) For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maximintegrated.com. 19-3701 Rev 2 1/12MAX270/MAX271 Digitally-Programmed, Dual 2nd-Order Continuous Lowpass Filter ABSOLUTE MAXIMUM RATINGS V+ to V- .................................................................-0.3V to +17V SO (W) (derate 11.7mW/NC above +70NC) .................. 941mw V+ to GND ............................................................-0.3V to +8.5V Operating Temperature Ranges: V- to GND ..............................................................-0.3V to -8.5V MAX27 C ....................................................... 0NC to +70NC Input Voltage to GND, Any Input Pin ....(V- - 0.3V) to (V+ + 0.3V) MAX27 E .................................................... -40NC to +85NC Duration of Output Short Circuit to GND ...................Continuous Storage Temperature Range ............................ -65NC to +165NC Lead Temperature (soldering, 10s) ................................+300NC Continuous Power Dissipation (T = +70NC) A MAX270 Soldering Temperature (reflow) Lead(Pb)-free ...............................................................+260NC PDIP (derate 11.1mW/NC above +70NC) .....................889mW SO (W) (derate 10mW/NC above +70NC ......................800mW Containing lead(Pb) .....................................................+240NC MAX271 PDIP (derate 13.3mW/NC above +70NC) ...................1067mW 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, V- = -5V T = +25NC, unless otherwise noted.) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS FILTER CHARACTERISTICS Operating Frequency Range (Note 1) 2 MHz Programmed Cutoff Frequency (f ) C 1 to 25 kHz Range f code = 53 (2.536kHz typ) Q2.9 Programmed Cutoff Frequency C % Error f code = 127 (25kHz typ) Q9.5 C f = 1kHz -3.6 -2.4 f code = 0 (1kHz typ), IN C T = T to T A MIN MAX f = 8kHz -33 IN Filter Gain dB f = 25kHz -6 -0.5 IN f code = 127 (25kHz typ), C T = T to T A MIN MAX f = 200kHz -34 IN f code = 0 (1kHz typ) 0.15 C Maximum Gain (Peaking) dB f code = 127 (25kHz typ) 0.15 C f code = 0 C 12 (1kHz typ) Wideband Noise 50Hz to 50kHz bandwidth FV RMS f code = 127 C 38 (25kHz typ) DC CHARACTERISTICS DC Output Signal Swing OUTA, OUTB, OP OUT (MAX270) R = 5kI, T = T to T -3 +3 V LOAD A MIN MAX OUTA, OUTB, T/H OUT (MAX271) Offset Voltage at Outputs OUTA, OUTB, OP OUT (MAX270) -2 +2 mV OUTA, OUTB, T/H OUT (MAX271) DC Input Leakage Current INA, INB (MAX270) T = T to T -1 +1 FA A MIN MAX INA, INB (MAX271) 2 Maxim Integrated