MAX291_09 Datasheet, PDF (1/10 Pages) Maxim Integrated Products – 8th-Order, Lowpass, Switched-Capacitor Filters

19-4526; Rev 4; 4/09
8th-Order, Lowpass,
Switched-Capacitor Filters
General Description
The MAX291/MAX292/MAX295/MAX296 are easy-to-use,
8th-order, lowpass, switched-capacitor filters that can be
set up with corner frequencies from 0.1Hz to 25kHz
(MAX291/MAX292) or 0.1Hz to 50kHz (MAX295/MAX296).
The MAX291/MAX295 Butterworth filters provide maxi-
mally flat passband response, and the MAX292/MAX296
Bessel filters provide low overshoot and fast settling. All
four filters have fixed responses, so the design task is
limited to selecting the clock frequency that controls the
filter’s corner frequency.
An external capacitor is used to generate a clock using
the internal oscillator, or an external clock signal can be
used. An uncommitted operational amplifier (noninverting
input grounded) is provided for building a continuous-
time lowpass filter for post-filtering or anti-aliasing.
Produced in an 8-pin DIP/SO and a 16-pin wide SO
package, and requiring a minimum of external compo-
nents, the MAX291 series delivers very aggressive per-
formance from a tiny area.
Applications
ADC Anti-Aliasing Filter
Noise Analysis
DAC Post-Filtering
50Hz/60Hz Line-Noise Filtering
Typical Operating Circuit
+5V
INPUT
8 _IN
CLOCK
1 _CLK
6
7
V+
MAX29_
V-
2
OUT ⁵
OP OUT ³
4
OP IN-
OUTPUT
Features
o 8th-Order Lowpass Filters:
Butterworth (MAX291/MAX295)
Bessel
(MAX292/MAX296)
o Clock-Tunable Corner-Frequency Range:
0.1Hz to 25kHz (MAX291/MAX292)
0.1Hz to 50kHz (MAX295/MAX296)
o No External Resistors or Capacitors Required
o Internal or External Clock
o Clock to Corner Frequency Ratio:
100:1 (MAX291/MAX292)
50:1 (MAX295/MAX296)
o Low Noise: -70dB THD + Noise (Typ)
o Operate with a Single +5V Supply or
Dual ±5V Supplies
o Uncommitted Op Amp for Anti-Aliasing or Clock-
Noise Filtering
o 8-Pin DIP and SO Packages
Ordering Information
PART
MAX291CPA
MAX291CSA
MAX291CWE
MAX291C/D
MAX291EPA
MAX291ESA
MAX291EWE
MAX291MJA
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
PIN-PACKAGE
8 Plastic DIP
8 SO
16 Wide SO
Dice*
8 Plastic DIP
8 SO
16 Wide SO
8 CERDIP**
Ordering Information continued on last page.
* Contact factory for dice specifications.
** Contact factory for availability and processing to MIL-STD-883.
TOP VIEW
Pin Configurations
CLK 1
V- ²
OP OUT 3
OP IN- 4
MAX29_
8 IN
7 V+
6 GND
5 OUT
-5V
Pin Configuration is 8-pin DIP/SO.
DIP/SO
16-pin Wide SO on last page.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.