MAX296EWE+T [MAXIM]
Switched Capacitor Filter, 1 Func, Bessel, Lowpass, PDSO16, SOP-16;
| 型号： | MAX296EWE+T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Switched Capacitor Filter, 1 Func, Bessel, Lowpass, PDSO16, SOP-16 LTE 光电二极管 有源滤波器 |
| 文件： | 总10页 (文件大小：339K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MAX291/MAX292/
MAX295/MAX296
8th-Order, Lowpass,
Switched-Capacitor Filters
General Description
Features
o 8th-Order Lowpass Filters:
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).
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
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.
o Clock to Corner Frequency Ratio:
100:1 (MAX291/MAX292)
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.
50:1 (MAX295/MAX296)
o Low Noise: -70dB THD + Noise (Typ)
o Operate with a Single +5V Supply or
Dual 5V Supplies
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.
o Uncommitted Op Amp for Anti-Aliasing or Clock-
Noise Filtering
o 8-Pin DIP and SO Packages
Ordering Information
Applications
ADC Anti-Aliasing Filter
Noise Analysis
PART
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**
MAX291CPA
MAX291CSA
MAX291CWE
MAX291C/D
MAX291EPA
MAX291ESA
MAX291EWE
MAX291MJA
DAC Post-Filtering
50Hz/60Hz Line-Noise Filtering
Ordering Information continued at end of data sheet.
* Contact factory for dice specifications.
Typical Operating Circuit
** Contact factory for availability and processing to MIL-STD-883.
+5V
Pin Configurations
7
V+
8
1
TOP VIEW
5
3
INPUT
IN
OUT
OUTPUT
OP OUT
1
2
3
4
8
7
6
5
IN
CLK
V-
MAX29_
V+
MAX29_
4
CLOCK
CLK
OP IN-
GND
OUT
OP OUT
OP IN-
6
V-
2
-5V
DIP/SO
Pin Configuration is 8-pin DIP/SO.
16-pin Wide SO at end of data sheet.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-4526; Rev 5; 5/10
MAX291/MAX292/MAX295/MAX296
8th-Order, Lowpass,
Switched-Capacitor Filters
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V+ to V-).......................................................12V
Operating Temperature Ranges
Input Voltage at Any Pin.............V- + (-0.3V) ≤ V ≤ V+ + (0.3V)
MAX29_C_ _........................................................0°C to +70°C
MAX29_E_ _.....................................................-40°C to +85°C
MAX29_MJA ..................................................-55°C to +125°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+240°C
IN
Continuous Power Dissipation
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ...727mW
8-Pin SO (derate 5.88mW/°C above +70°C)................471mW
16-Pin Wide SO (derate 9.52mW/°C above +70°C) ....762mW
8-Pin CERDIP (derate 8.00mW/°C above +70°C)........640mW
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, filter output measured at OUT pin, 20kΩ load resistor to ground at OUT and OP OUT, f
= 100kHz
CLK
(MAX291/MAX292) or f
= 50kHz (MAX295/MAX296), T = T
to T
, unless otherwise noted.)
MAX
CLK
A
MIN
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
FILTER CHARACTERISTICS
MAX291/MAX292
MAX295/MAX296
MAX291/MAX292
MAX295/MAX296
MAX291
0.1-25k
0.1-50k
100:1
50:1
10
Corner-Frequency Range
Hz
Clock to Corner
Frequency Ratio
MAX292
MAX295
40
5
Clock to Corner
Frequency Tempco
ppm/°C
MAX296
60
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
f
IN
= 0.50 F
-0.02
-2.7
-0.1
-3.2
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
= 1.00 F
= 2.00 F
= 3.00 F
= 0.25 F
= 0.50 F
= 1.00 F
= 2.00 F
= 3.00 F
= 4.00 F
= 6.00 F
= 0.50 F
= 1.00 F
= 2.00 F
= 3.00 F
= 0.25 F
= 0.50 F
= 1.00 F
= 2.00 F
= 3.00 F
= 4.00 F
= 6.00 F
-2.2
-43.0
-70.0
-0.1
MAX291
MAX292
MAX295
MAX296
-48.0
-76.0
-0.2
-0.3
-1.0
-0.6
-0.8
-2.7
-3.0
-3.3
-11.0
-30.0
-47.0
-74.0
-13.0
-34.0
-51.0
-78.0
-0.02
-2.7
-15.0
Insertion Gain Relative to
DC Gain
dB
-0.1
-3.2
-2.2
-43.0
-70.0
-0.1
-48.0
-76.0
-0.2
-0.3
-1.0
-0.6
-0.8
-2.7
-3.0
-3.3
-11.0
-30.0
-47.0
-74.0
-13.0
-34.0
-51.0
-78.0
-15.0
2
Maxim Integrated
MAX291/MAX292/MAX295/MAX296
8th-Order, Lowpass,
Switched-Capacitor Filters
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 5V, V- = -5V, filter output measured at OUT pin, 20kΩ load resistor to ground at OUT and OP OUT, f
= 100kHz
CLK
(MAX291/MAX292) or f
= 50kHz (MAX295/MAX296), T = T
to T , unless otherwise noted.)
MAX
CLK
A
MIN
PARAMETER
Output DC Swing
CONDITIONS
MIN
4
TYP
MAX
UNITS
V
Output Offset Voltage
IN = GND
150
0
400
mV
DC Insertion Gain Error with
Output Offset Removed
0.15
-0.15
dB
Total Harmonic Distortion
plus Noise
T
= +25°C, f
= 100kHz
-70
6
dB
A
CLK
Clock Feedthrough
f
= 100kHz
mVp-p
CLK
CLOCK
Internal Oscillator
Frequency
C
= 1000pF
= 0V or 5V
29
35
70
43
kHz
µA
OSC
Internal Oscillator
Current Source/Sink
V
CLK
120
Clock Input High
(Note 1)
4.0
V
V
Low
1.0
50
UNCOMMITTED OP AMP
Input Offset Voltage
Output DC Swing
Input Bias Current
POWER REQUIREMENTS
10
mV
V
µA
4
0.05
Supply Voltage
Dual Supply
2.375
4.750
5.500
V
V
Single Supply
V- = 0V, GND = V 2
V+ = 5V, V- = -5V, V
V+ = 2.375V, V- = -2.375V, V
11.000
22
12
= 0V to 5V
15
7
CLK
Supply Current
mA
= -2V to 2V
CLK
Note 1. Guaranteed by design.
Typical Operating Characteristics
(V+ = 5V, V- = -5V, T = +25°C, f
= 100kHz (MAX291/MAX292) or f
= 50kHz (MAX295/MAX296), unless otherwise noted.)
A
CLK
CLK
INTERNAL OSCILLATOR PERIOD vs.
CAPACITANCE VALUE
NORMALIZED INTERNAL OSCILLATOR
FREQUENCY vs. SUPPLY VOLTAGE
NORMALIZED INTERNAL OSCILLATOR
FREQUENCY vs. TEMPERATURE
500
450
400
350
300
250
200
150
100
50
1nF EXTERNAL
CAPACITOR CLK
1nF EXTERNAL
CAPACITOR CLK
1.06
1.030
1.020
1.010
1.03
1.00
0.97
0.94
1.000
0.990
0
0
4
6
8
10 12 14 16 18
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
-60 -40 -20
0
20 40 60 80 100 120 140
CAPACITANCE (nF)
TEMPERATURE (°C)
Maxim Integrated
3
MAX291/MAX292/MAX295/MAX296
8th-Order, Lowpass,
Switched-Capacitor Filters
Typical Operating Characteristics (continued)
(V+ = 5V, V- = -5V, T = +25°C, f
A
= 100kHz (MAX291/MAX292) or f
= 50kHz (MAX295/MAX296), unless otherwise noted.)
CLK
CLK
MAX292/MAX296
FREQUENCY RESPONSE
MAX291/MAX295
FREQUENCY RESPONSE
MAX291/MAX295
FREQUENCY RESPONSE
20
0
0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
-0.7
20
0
F = 1kHz
F = 1kHz
o
F = 1kHz
o
o
MAX291
MAX295
-20
-40
-60
-80
-100
-120
-20
-40
-60
-80
-100
-120
MAX296
MAX291
MAX292
6
MAX295
4
0
2
4
8
10
0
200
400
600
800
1k
0
1
2
3
5
INPUT FREQUENCY (Hz)
INPUT FREQUENCY (Hz)
INPUT FREQUENCY (Hz)
MAX291/MAX295
SUPPLY CURRENT
MAX292/MAX296
FREQUENCY RESPONSE
vs. SUPPLY VOLTAGE
FREQUENCY RESPONSE
0
-10
-20
-30
-40
-50
-60
-70
16
15
14
13
12
11
10
9
0
100kHz EXTERNAL CLOCK
F = 1kHz
F = 1kHz
o
o
-2
-4
MAX296
MAX292
-6
MAX291/MAX295
-8
-10
-12
-14
8
7
6
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE, V+ OR |V-|
0
400
800
1.2k
1.6k
2k
0
400
800
1.2k
1.6k
2k
INPUT FREQUENCY (Hz)
INPUT FREQUENCY (Hz)
MAX291/MAX295
PHASE RESPONSE
SUPPLY CURRENT vs. TEMPERATURE
MAX292/296 PHASE RESPONSE
0
16
15
14
13
12
11
10
0
-80
100kHz EXTERNAL CLOCK
I+ OR | I- |
f = 1kHz
o
F = 1kHz
o
-50
-100
-150
-200
-250
-300
-160
-240
-320
-400
-480
-560
MAX291
-350
MAX295
-60 -40 -20
0
20 40 60 80 100 120 140
0
400
800
1.2k
1.6k
2k
0
400
800
1.2k
1.6k
2k
TEMPERATURE (°C)
INPUT FREQUENCY (Hz)
INPUT FREQUENCY (Hz)
4
Maxim Integrated
MAX291/MAX292/MAX295/MAX296
8th-Order, Lowpass,
Switched-Capacitor Filters
Typical Operating Characteristics (continued)
(V+ = 5V, V- = -5V, R
= 5kΩ, T = +25°C, unless otherwise noted.)
A
LOAD
MAX296 LOW-VOLTAGE
FREQUENCY RESPONSE
MAX291 LOW-VOLTAGE
FREQUENCY RESPONSE
MAX291 THD + NOISE vs.
INPUT SIGNAL AMPLITUDE
-40
-45
-50
-55
-60
-65
-70
-75
0
A: f = 200kHz F = 2kHz
INPUT FREQ. = 200Hz
MEAS. BANDWIDTH = 30kHz
CLK
o
V+ = +2.5V
V- = -2.5V
V+ = +2.5V
V- = -2.5V
0
-4
-4
-8
B: f = 1MHz F = 1kHz
CLK
o
-8
INPUT FREQ. = 1kHz
MEAS. BANDWIDTH = 80kHz
F
= 20kHz
C
-12
-12
-16
-20
-24
F
= 2kHz
A
C
-16
-20
F
= 20kHz
C
F
= 1kHz
1.3
C
-24
-28
B
-28
-80
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
INPUT FREQUENCY (F/FC)
1.0
1.1
1.2
1.4
1.5
1
2
3
4
5
6
7
8
9
10
INPUT FREQUENCY (F/FC)
AMPLITUDE (Vp-p)
MAX291 LOW-FREQUENCY
PHASE RESPONSE
MAX292 THD + NOISE vs.
INPUT SIGNAL AMPLITUDE
MAX296 LOW-VOLTAGE PHASE RESPONSE
-40
-45
-50
-55
-60
-65
-70
-75
A: f = 200kHz F = 2kHz
INPUT FREQ. = 200Hz
MEAS. BANDWIDTH = 30kHz
CLK
o
V+ = +2.5V
V- = -2.5V
V+ = +2.5V
V- = -2.5V
0
0
-80
-160
-240
-320
-400
-480
-90
-180
-270
-360
-450
-540
B: f = 1MHz F = 1kHz
CLK
o
INPUT FREQ. = 1kHz
MEAS. BANDWIDTH = 80kHz
F
= 20kHz
C
F
= 20kHz
B
C
F
= 2kHz
C
F
= 1kHz
C
A
-560
-80
-630
1.0
1.1
1.2
1.3
1.4
1.5
1
2
3
4
5
6
7
8
9
10
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
INPUT FREQUENCY (F/FC)
INPUT FREQUENCY (F/FC)
AMPLITUDE (Vp-p)
MAX295 THD + NOISE vs.
INPUT SIGNAL AMPLITUDE
MAX296 THD + NOISE vs.
INPUT SIGNAL AMPLITUDE
-40
-45
-50
-55
-60
-65
-70
-75
-40
-45
-50
-55
-60
-65
-70
-75
C: f = 200kHz F = 4kHz
INPUT FREQ. = 400Hz
MEAS. BANDWIDTH = 30kHz
C: f = 200kHz F = 4kHz
INPUT FREQ. = 400Hz
MEAS. BANDWIDTH = 30kHz
CLK
o
CLK
o
D: f = 1MHz F = 20kHz
D: f = 1MHz F = 20kHz
CLK
o
CLK
o
INPUT FREQ. = 2kHz
MEAS. BANDWIDTH = 80kHz
INPUT FREQ. = 2kHz
MEAS. BANDWIDTH = 80kHz
D
D
C
C
-80
-80
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
AMPLITUDE (Vp-p)
AMPLITUDE (Vp-p)
Maxim Integrated
5
MAX291/MAX292/MAX295/MAX296
8th-Order, Lowpass,
Switched-Capacitor Filters
_____________________Pin Description
A
8-PIN 16-PIN
NAME
FUNCTION
1, 2, 7,
8, 9, 10,
15, 16
B
N.C.
No Connect
C
Clock Input. Use internal or
external clock.
1
3
CLK
Negative Supply pin. Dual
supplies: -2.375V to -5.500V.
Single supplies: V- = 0V.
TIME (200µs/div)
2
3
4
5
6
4
5
V-
A: 3kHz INPUT SIGNAL
B: MAX292 BESSEL FILTER RESPONSE WITH F = 10kHz
OP OUT
OP IN-
OUT
Uncommitted Op-Amp Output
o
C: MAX291 BUTTERWORTH FILTER RESPONSE WITH F = 10kHz
o
Inverting Input to the uncommit-
ted op amp. The noninverting op
amp is internally tied to ground.
6
Figure 1. Bessel vs. Butterworth Filter Responses
11
12
Filter Output
The MAX291/MAX295 give more attenuation outside the
passband. The phase and frequency response curves in
the Typical Operating Characteristics reveal the differences
between the two types of filters.
Ground. In single-supply oper-
ation, GND must be biased to
the mid-supply voltage level.
GND
Positive Supply pin. Dual sup-
plies: +2.375V to +5.500V. Single
supplies: +4.75V to +11.0V.
MAX291/MAX292/MAX295/MAX296 phase shift and gain
do not vary significantly from part to part. Typical phase
shift and gain differences are less than 0.5% at the corner
7
8
13
14
V+
IN
Filter Input
frequency (F ).
C
_______________Detailed Description
Corner Frequency and Filter Attenuation
The MAX291/MAX292 operate with a 100:1 clock to corner
frequency ratio and a 25kHz maximum corner frequency,
where corner frequency is defined as the point where the
filter output is 3dB below the filter’s DC gain. The
MAX295/MAX296 operate with a 50:1 clock to corner fre-
quency ratio with a 50kHz maximum corner frequency.
The 8 poles provide 48dB of attenuation per octave.
Lowpass Butterworth filters such as the MAX291/
MAX295 provide maximally flat passband response, making
them ideal for instrumentation applications that require mini-
mum deviation from the DC gain throughout the passband.
Lowpass Bessel filters such as the MAX292/MAX296
delay all frequency components equally, preserving the
shape of step inputs, subject to the attenuation of the high-
er frequencies. They also settle faster than Butterworth fil-
ters. Faster settling can be important in applications that
use a multiplexer (mux) to select one signal to be sent to
an analog-to-digital converter (ADC)—an anti-aliasing filter
placed between the mux and the ADC must settle quickly
after a new channel is selected by the mux.
Background Information
Most switched-capacitor filters are designed with biqua-
dratic sections. Each section implements two filtering
poles, and the sections can be cascaded to produce high-
er-order filters. The advantage to this approach is ease of
design. However, this type of design can display poor sen-
sitivity if any section’s Q is high.
The difference in the filters’ responses can be observed
when a 3kHz square wave is applied to the filter input
(Figure 1, trace A). With the filter cutoff frequencies set at
10kHz, trace C shows the MAX291/MAX295 Butterworth
filter response and trace B shows the MAX292/MAX296
Bessel filter response. Since the MAX292/MAX296 have a
linear phase response in the passband, all frequency
components are delayed equally, which preserves the
square wave. The filters attenuate higher frequencies of
the input square wave, giving rise to the rounded edges at
the output. The MAX291/MAX295 delay different frequen-
cy components by varying times, causing the overshoot
and ringing own in trace C.
An alternative approach is to emulate a passive network
using switched-capacitor integrators with summing and
scaling. The passive network can be synthesized using
CAD programs, or can be found in many filter books.
Figure 2 shows the basic ladder filter structure.
A switched-capacitor filter that emulates a passive ladder
filter retains many of its advantages. The filter’s com-
ponent sensitivity is low when compared to a cascaded
biquad design because each component affects the entire
filter shape, not just one pole pair. That is, a mismatched
component in a biquad design will have a concentrated
6
Maxim Integrated
MAX291/MAX292/MAX295/MAX296
8th-Order, Lowpass,
Switched-Capacitor Filters
+5V
7
V+
1
3
R1
L1
L3
L5
L7
CLK
5
6
+5V
0V
OUTPUT
OUT
GND
OP OUT
10k
10k
0.1µF
MAX29_
4
8
C2
C4
C6
C8
R2
OP IN-
+1V TO +4V
INPUT SIGNAL
RANGE
IN
V
IN
V
O
V-
0.1µF
2
0V
Pin Configuration is 8-pin DIP.
Figure 3. +5V Single-Supply Operation
Figure 2. 8th-Order Ladder Filter Network
error on its respective poles, while the same mismatch in a
ladder filter design will spread its error over all poles.
clock frequency over the clock range 100kHz to 1MHz.
Varying the rate of an external clock will dynamically ad-
just the corner frequency of the filter.
The MAX291/MAX292/MAX295/MAX296 input impedance
is effectively that of a switched-capacitor resistor (see
equation below, and Table 1), and it is inversely proportion-
al to frequency. The input impedance values determined
below represent average input impedance, since the input
current is not continuous. The input current flows in a series
of pulses that charge the input capacitor every time the
appropriate switch is closed. A good rule of thumb is that
the driver’s input source resistance should be less than
10% of the filter’s input impedance. The input impedance
of the filter can be estimated using the following formula:
Ideally, the MAX291/MAX292/MAX295/MAX296 should
be clocked symmetrically (50% duty cycle). MAX291/
MAX292/MAX295/MAX296 can be operated with clock
asymmetry of up to 60/40% (or 40/60%) if the clock
remains HIGH and LOW for at least 200ns. For example,
if the part has a maximum clock rate of 2.5MHz, then the
clock should be high for at least 200ns, and low for at
least 200ns.
When using the internal oscillator, the capacitance (C
)
OSC
from CLK to ground determines the oscillator frequency:
Z = 1 / (f
* C)
CLK
5
10
f
(kHz) ≈
OSC
where: f
= Clock Frequency
CLK
3C
(pF)
OSC
The input impedance for various clock frequencies is
given below:
The stray capacitance at CLK should be minimized be-
cause it will affect the internal oscillator frequency.
Table 1. Input Impedance for Various Clock
Frequencies
___________Application Information
Power Supplies
The MAX291/MAX292/MAX295/MAX296 operate from
either dual or single power supplies. The dual-supply volt-
age range is +2.375V to +5.500V. The 2.5V dual supply is
equivalent to single-supply operation (Figure 3). Minor per-
formance degradation could occur due to the external
resistor divider network, where the GND pin is biased to
mid-supply.
10kHz
100kHz
1000kHz
PART
C (pF)
(MΩ)
(MΩ)
(kΩ)
MAX291
MAX292
MAX295
MAX296
2.24
3.28
4.47
4.22
44.6
30.5
22.4
23.7
4.46
3.05
2.24
2.37
446
305
224
237
Clock-Signal Requirements
The MAX291/MAX292/MAX295/MAX296 maximum rec-
ommended clock frequency is 2.5MHz, producing a cutoff
frequency of 25kHz for the MAX291/MAX292 and 50kHz
for the MAX295/MAX296. The CLK pin can be driven by
an external clock or by the internal oscillator with an exter-
nal capacitor. For external clock applications, the clock
circuitry has been designed to interface with +5V CMOS
logic. Drive the CLK pin with a CMOS gate powered from
0V and +5V when using either a single +5V supply or dual
+5V supplies. The MAX291/MAX292/MAX295/MAX296
supply curt increases slightly (<3%) with increasing
Input Signal Range
The ideal input signal range is determined by observing at
what voltage level the total harmonic distortion plus noise
(THD + Noise) ratio is maximized for a given corner fre-
quency. The Typical Operating Characteristics show the
MAX291/MAX292/MAX295/MAX296 THD + Noise response
as the input signal’s peak-to-peak amplitude is varied.
Uncommitted Op Amp
The uncommitted op amp has its noninverting input tied
to the GND pin, and can be used to build a 1st- or 2nd-
Maxim Integrated
7
MAX291/MAX292/MAX295/MAX296
8th-Order, Lowpass,
Switched-Capacitor Filters
22k
_Ordering Information (continued)
C1
PART
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
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
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**
8 Plastic DIP
8 SO
R2
330pF
OP IN
MAX292CPA
MAX292CSA
MAX292CWE
MAX292C/D
MAX292EPA
MAX292ESA
MAX292EWE
MAX292MJA
MAX295CPA
MAX295CSA
MAX295CWE
MAX295C/D
MAX295EPA
MAX295ESA
MAX295EWE
MAX295MJA
MAX296CPA
MAX296CSA
MAX296CWE
MAX296C/D
MAX296EPA
MAX296ESA
MAX296EWE
MAX296MJA
22k
R1
22k
R3
4
INPUT
OUTPUT
C2
1500pF
3
OP OUT
MAX29_
Pin Configuration is 8-pin DIP/SO.
Figure 4. Uncommitted Op Amp Configured as a 2nd-Order
Butterworth Lowpass Filter (F = 10kHz)
o
16 Wide SO
Dice*
8 Plastic DIP
8 SO
16 Wide SO
8 CERDIP**
8 Plastic DIP
8 SO
16 Wide SO
Dice*
order continuous lowpass filter. This filter is convenient for
anti-aliasing applications, or for clock noise attenuation at
the switched-capacitor filter’s output. Figure 4 shows a
2nd-order lowpass Butterworth filter built using the
uncommitted op amp with a 10kHz corner frequency.
This filter’s input resistance of 22k satisfies the minimum
load requirements of the switched-capacitor filter.
The uncommitted op amp (with a 2MHz gain bandwidth
product) can alternatively be used at the input of the
switched-capacitor filter to help reduce any possible
clock ripple feedthrough to the output.
8 Plastic DIP
8 SO
16 Wide SO
8 CERDIP**
DAC Post-Filtering
When using the MAX291/MAX292/MAX295/MAX296 for
DAC post-filtering, synchronize the DAC and the filter
clocks. If clocks are not synchronized, beat frequen-
cies will alias into the desired passband. The DAC’s
clock should be generated by dividing down the
switched-capacitor filter’s clock.
* Contact factory for dice specifications.
** Contact factory for availability and processing to MIL-STD-883.
Harmonic Distortion
Harmonic distortion arises from nonlinearities within the
filters. These nonlinearities generate harmonics when a
pure sine wave is applied to the filter input. Table 2 lists
typical harmonic distortion values for the MAX291/
MAX292/MAX295/MAX296 with a 1kHz 5Vp-p sine-wave
input signal, a 1MHz clock frequency, and a 5kΩ load.
Table 2. Typical Harmonic Distortion (dB)
Harmonic
2nd
-72
-71
-93
-71
3rd
-78
-82
-86
-89
4th
-83
-82
-92
-96
5th
-89
-88
-97
-96
MAX291
MAX292
MAX295
MAX296
Filter
8
Maxim Integrated
MAX291/MAX292/MAX295/MAX296
8th-Order, Lowpass,
Switched-Capacitor Filters
____Pin Configurations (continued)
Package Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in
the package code indicates RoHS status only. Package draw-
ings may show a different suffix character, but the drawing per-
tains to the package regardless of RoHS status.
TOP VIEW
N.C.
N.C.
N.C.
N.C.
IN
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
CLK
8 CERDIP
8 Plastic DIP
8 SO
J8-2
21-0045
21-0043
21-0041
21-0042
V-
V+
MAX29_
P8-2
OP OUT
OP IN-
N.C.
GND
OUT
N.C.
N.C.
S8-5
16 Wide SO
W16-1
N.C.
WIDE SO
Maxim Integrated
9
MAX291/MAX292/MAX295/MAX296
8th-Order, Lowpass,
Switched-Capacitor Filters
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
DESCRIPTION
3
4
5
12/97
4/09
5/10
—
—
8
Added MAX292 to Ordering Information table and added new Package
Information section
Changed voltage range in Figure 7
7
Maxim cannot me responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.
Maxim reserves he right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical
Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
10
Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
©
The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc.
2010 Maxim Integrated
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