19-0352; Rev 2; 7/02
Microprocessor Programmable
Universal Active Filters
General Description
Features
The MAX260/MAX261/MAX262 CMOS dual second-
order universal switched-capacitor active filters allow
microprocessor control of precise filter functions. No
external components are required for a variety of band-
pass, lowpass, highpass, notch, and allpass configura-
tions. Each device contains two second-order filter
sections that place center frequency, Q, and filter oper-
ating mode under programmed control.
o Filter Design Software Available
o Microprocessor Interface
o 64-Step Center Frequency Control
o 128-Step Q Control
o Independent Q and f Programming
0
o Guaranteed Clock to f Ratio-1% (A grade)
0
An input clock, along with a 6-bit f program input,
0
determine the filter's center or corner frequency without
affecting other filter parameters. The filter Q is also pro-
grammed independently. Separate clock inputs for
each filter section operate with either a crystal, RC net-
work, or external clock generator.
o 75kHz f Range (MAX262)
0
o Single +5V and 5V ꢀperation
Ordering Information
The MAX260 has offset and DC specifications superior
to the MAX261 and MAX262 and a center frequency
(f ) range of 7.5kHz. The MAX261 handles center fre-
0
quencies to 57kHz, while the MAX262 extends the cen-
ter frequency range to 140kHz by employing lower
clock-to-f ratios. All devices are available in 24-pin DIP
0
PART
TEMP RANGE PACKAGE ACCURACY
MAX260ACNG
MAX260BCNG
0°C to +70°C
0°C to +70°C
Plastic DIP
Plastic DIP
Plastic DIP
Plastic DIP
Wide SO
1%
2%
1%
2%
1%
2%
1%
2%
MAX260AENG -40°C to +85°C
MAX260BENG -40°C to +85°C
and small outline packages in commercial, extended,
and military temperature ranges.
MAX260ACWG
MAX260BCWG
0°C to +70°C
0°C to +70°C
Wide SO
Applications
MAX260AMRG -55°C to +125°C CERDIP
MAX260BMRG -55°C to +125°C CERDIP
*All devices—24-pin packages 0.3in-wide packages
µP-Tuned Filters
Anti-Aliasing Filters
Digital Signal Processing
Adaptive Filters
Ordering Information continued at end of data sheet.
Signal Analysis
Pin Configurations
Phase-Locked Loops
TOP VIEW
Functional Diagram
BP
A
1
2
3
4
5
6
7
8
9
24 LP
BP
1
2
3
4
5
6
7
8
9
24 LP
A
A
A
B
OUTPUT
INPUT
N.C.
HP
23 IN
OP OUT
HP
23 IN
B
B
IN LP HP BP
IN LP HP BP
22 LP
22 LP
21 BP
A
B
A
N.C.
IN
21 BP
20 D0
OP IN
IN
B
B
FILTER
A
FILTER
B
+
+5V
-5V
V
MAX260
MAX261
MAX262
20 HP
19 D0
A
A
B
D1
A3
19 OSC OUT
D1
A3
18 GND
-
18 OSC OUT
GND
GND
-
CLK OUT
17
V
CLK OUT
17
16
15
+
+
V
V
16 WR
15 A0
V
MAX260
MAX261
MAX262
WR
A2 10
CLK 11
A2 10
CLK 11
-
V
14 HP
14 A0
13 A1
A
B
A
CLK
OSC CLKOUT
CLK
B
A
CLK 12
13 A1
CLK 12
B
B
PROGRAM
INPUTS
CRYSTAL
FOURTH-ORDER BANDPASS FILTER
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.