Rainbow Electronics MAX7425 - Manual

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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 CT2 Base Stations
DAC Postfiltering Speech Processing
Features
♦ 5th-Order, Lowpass Filters
Elliptic Response (MAX7418/MAX7421/
MAX7422/MAX7425)
Bessel Response (MAX7419/MAX7423)
Butterworth Response (MAX7420/MAX7424)
♦ Clock-Turnable Corner Frequency (1Hz to 45kHz)
♦ Single-Supply Operation
+5V (MAX7418–MAX7421)
+3V (MAX7422–MAX7425)
♦ Low Power
3mA (Operating Mode)
0.2µA (Shutdown Mode)
♦ Available in 8-Pin µMAX Package
♦ Low Output Offset: ±4mV
MAX7418–MAX7425
5th-Order, Lowpass,
Switched-Capacitor Filters
________________________________________________________________ Maxim Integrated Products 1
OS
OUT V DD
1
2
8
7
CLK
SHDN IN
GND
COM
µMAX
TOP VIEW
3
4
6
5
MAX7418–
MAX7425
V DD
IN
CLK
OUT
GND
INPUT
0.1 µF
0.1 µF
CLOCK
SHDN
OUTPUT
V
SUPPLY
COM
OS
MAX7418–
MAX7425
Typical Operating Circuit
19-1821; Rev 0; 11/00
Pin Configuration
Ordering Information
Selector Guide
PART
MAX7418EUA -40°C to +85°C
TEMP. RANGE PIN-PACKAGE
8 µMAX
Selector Guide continued at end of data sheet.
Ordering Information continued at end of data sheet.
MAX7418CUA 0°C to +70°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
PART FILTER RESPONSE
OPERATING
VOLTAGE (V)
MAX7418 r = 1.6 +5
MAX7419 Bessel +5
MAX7420 Butterworth +5
MAX7421 r = 1.25 +5