MAX7418 Datasheet, PDF (1/14 Pages) Maxim Integrated Products – 5th-Order, Lowpass, Switched-Capacitor Filters

19-1821; Rev 0; 11/00
5th-Order, Lowpass,
Switched-Capacitor Filters
General Description
The MAX7418–MAX7425 5th-order, low-pass, switched-
capacitor filters (SCFs) operate from a single +5V
(MAX7418–MAX7421) or +3V (MAX7422–MAX7425)
supply. These devices draw only 3mA of supply current
and allow corner frequencies from 1Hz to 45kHz, mak-
ing them ideal for low-power post-DAC filtering and anti-
aliasing applications. They feature a shutdown mode
that reduces supply current to 0.2µA.
Two clocking options are available: self-clocking
(through the use of an external capacitor), or external
clocking for tighter corner-frequency control. An offset
adjust pin allows for adjustment of the DC output level.
The MAX7418/MAX7422 deliver 53dB of stopband
rejection and a sharp rolloff with a 1.6 transition ratio.
The MAX7421/MAX7425 achieve a sharper rolloff with a
1.25 transition ratio while still providing 37dB of stop-
band rejection. The MAX7419/MAX7423 Bessel filters
provide low overshoot and fast settling, and the
MAX7420/MAX7424 Butterworth filters provide a maxi-
mally flat passband response. Their fixed response sim-
plifies the design task of selecting a clock frequency.
Applications
ADC Anti-Aliasing
DAC Postfiltering
CT2 Base Stations
Speech Processing
Selector Guide
PART
FILTER RESPONSE
OPERATING
VOLTAGE (V)
MAX7418
r = 1.6
+5
MAX7419
Bessel
+5
MAX7420
Butterworth
+5
MAX7421
r = 1.25
+5
Selector Guide continued at end of data sheet.
Pin Configuration
TOP VIEW
COM 1
IN 2
GND 3
V_DD 4
MAX7418–
MAX7425
8 CLK
7 SHDN
6 OS
5 OUT
µMAX
Features
o 5th-Order, Lowpass Filters
Elliptic Response (MAX7418/MAX7421/
MAX7422/MAX7425)
Bessel Response (MAX7419/MAX7423)
Butterworth Response (MAX7420/MAX7424)
o Clock-Turnable Corner Frequency (1Hz to 45kHz)
o Single-Supply Operation
+5V (MAX7418–MAX7421)
+3V (MAX7422–MAX7425)
o Low Power
3mA (Operating Mode)
0.2µA (Shutdown Mode)
o Available in 8-Pin µMAX Package
o Low Output Offset: ±4mV
Ordering Information
PART
TEMP. RANGE PIN-PACKAGE
MAX7418CUA
0°C to +70°C
8 µMAX
MAX7418EUA
-40°C to +85°C 8 µMAX
MAX7419CUA
0°C to +70°C
8 µMAX
MAX7419EUA
-40°C to +85°C 8 µMAX
MAX7420CUA
0°C to +70°C
8 µMAX
MAX7420EUA
-40°C to +85°C 8 µMAX
MAX7421CUA
0°C to +70°C
8 µMAX
MAX7421EUA
-40°C to +85°C 8 µMAX
Ordering Information continued at end of data sheet.
Typical Operating Circuit
V_SUPPLY
0.1µF
INPUT
CLOCK
V_DD
SHDN
IN
OUT
MAX7418–
MAX7425
CLK
COM
OS
GND
OUTPUT
0.1µF
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