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General Description
The MAX7409/MAX7410/MAX7413/MAX7414 5th-order,
lowpass, switched-capacitor filters (SCFs) operate from
a single +5V (MAX7409/MAX7410) or +3V (MAX7413/
MAX7414) supply. These devices draw only 1.2mA of
supply current and allow corner frequencies from 1Hz
to 15kHz, making them ideal for low-power post-DAC
filtering and anti-aliasing applications. They feature a
shutdown mode, which reduces the supply current to
0.2µA.
Two clocking options are available on these devices:
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 out-
put level.
The MAX7409/MAX7413 Bessel filters provide low over-
shoot and fast settling, while the MAX7410/MAX7414
Butterworth filters provide a maximally flat passband
response. Their fixed response simplifies the design
task to selecting a clock frequency.
Applications
ADC Anti-Aliasing CT2 Base Stations
DAC Postfiltering Speech Processing
Air-Bag Electronics
Features
♦5th-Order Lowpass Filters
Bessel Response (MAX7409/MAX7413)
Butterworth Response (MAX7410/MAX7414)
♦Clock-Tunable Corner Frequency (1Hz to 15kHz)
♦Single-Supply Operation
+5V (MAX7409/MAX7410)
+3V (MAX7413/MAX7414)
♦Low Power
1.2mA (operating mode)
0.2µA (shutdown mode)
♦Available in 8-Pin µMAX/DIP Packages
♦Low Output Offset: ±4mV
MAX7409/MAX7410/MAX7413/MAX7414
5th-Order, Lowpass,
Switched-Capacitor Filters
________________________________________________________________
Maxim Integrated Products
1
OS
OUTVDD
1
2
8
7
CLK
SHDNIN
GND
COM
µMAX/DIP
TOP VIEW
3
4
6
5
MAX7409
MAX7410
MAX7413
MAX7414
VDD
IN
CLK
OUT
GND
INPUT
0.1µF
0.1µF
CLOCK
SHDN
OUTPUT
VSUPPLY
COM
OS
MAX7409
MAX7410
MAX7413
MAX7414
Typical Operating Circuit
19-4766; Rev 1; 9/98
Pin Configuration
Ordering Information
PART FILTER RESPONSE OPERATING
VOLTAGE (V)
MAX7409 Bessel +5
MAX7410 Butterworth +5
Selector Guide
PART
MAX7409CPA
MAX7409EUA
MAX7409EPA -40°C to +85°C
-40°C to +85°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
8 Plastic DIP
8 µMAX
8 Plastic DIP
MAX7410CUA
MAX7410CPA
MAX7410EUA
MAX7410EPA -40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C 8 µMAX
8 Plastic DIP
8 µMAX
8 Plastic DIP
Ordering Information continued at end of data sheet.
MAX7413 Bessel +3
MAX7414 Butterworth +3
MAX7409CUA 0°C to +70°C 8 µMAX
MAX7409/MAX7410/MAX7413/MAX7414
5th-Order, Lowpass,
Switched-Capacitor Filters
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS—MAX7409/MAX7410
(VDD = +5V, filter output measured at OUT, 10kΩ|| 50pF load to GND at OUT, OS = COM, 0.1µF capacitor from COM to GND,
SHDN = VDD, fCLK = 100kHz, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
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.
VDD to GND..............................................................-0.3V to +6V
IN, OUT, COM, OS, CLK, SHDN ................-0.3V to (VDD + 0.3V)
OUT Short-Circuit Duration...................................................1sec
Continuous Power Dissipation (TA= +70°C)
8-Pin DIP (derate 9.09mW/°C above +70°C)...............727mW
8-Pin µMAX (derate 4.1mW/°C above +70°C).............330mW
Operating Temperature Ranges
MAX74 _ _C_A ...................................................0°C to +70°C
MAX74 _ _E_A ................................................-40°C to +85°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10sec).............................+300°C
COSC = 1000pF (Note 3)
VOS = 0 to VDD
SHDN = GND, VCOM = 0 to VDD
(Note 1)
Input, COM externally driven
OS to OUT
Input, OS externally driven
fIN = 200Hz, VIN = 4Vp-p,
measurement bandwidth = 22kHz
VIN = VCOM = VDD / 2
VCOM = VDD / 2 (Note 2)
Output, COM unconnected
CONDITIONS
21 30 38fOSC
Internal Oscillator Frequency
±0.1 ±10Input Leakage Current at OS ±0.1 ±10Input Leakage Current at COM
50 500CL
10 1RL
Resistive Output Load Drive 5Clock Feedthrough 110 180RCOM
Input Resistance at COM VCOM ±0.1VOS
2.3 2.5 2.7
100:1fCLK / fc
Clock-to-Corner Ratio 0.001 to 15fc
Corner Frequency
VCOM
1AOS
Offset Voltage Gain
-85
THD+N
Total Harmonic Distortion
plus Noise
10Clock-to-Corner Tempco 0.25 VDD - 0.25Output Voltage Range ±4 ±25VOFFSET
Output Offset Voltage
-0.2 0 0.2
DC Insertion Gain with
Output Offset Removed
MIN TYP MAX
SYMBOLPARAMETER
VCLK = 0 or 5V
0.5VIL
Clock Input Low 4.5VIH
Clock Input High
±13.5 ±20ICLK
Clock Output Current
(Internal Oscillator Mode)
V
V
µA
kHz
µA
µA
pF
kΩ
mVp-p
kΩ
V
V
V/V
dB
dB
mV
V
ppm/°C
kHz
UNITS
Maximum Capacitive Output
Load Drive
FILTER CHARACTERISTICS
CLOCK
MAX7409
MAX7410 -78
COM Voltage Range 2.0 2.5 3.0
Input Voltage Range at OS
MAX7409/MAX7410/MAX7413/MAX7414
5th-Order, Lowpass,
Switched-Capacitor Filters
_______________________________________________________________________________________ 3
5th-Order, Lowpass,
Switched-Capacitor Filters
ELECTRICAL CHARACTERISTICS—MAX7409/MAX7410
(VDD = +5V, filter output measured at OUT, 10kΩ|| 50pF load to GND at OUT, OS = COM, 0.1µF capacitor from COM to GND,
SHDN = VDD, fCLK = 100kHz, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
ELECTRICAL CHARACTERISTICS—MAX7413/MAX7414
(VDD = +3V, filter output measured at OUT pin, 10kΩ|| 50pF load to GND at OUT, OS = COM, 0.1µF capacitor from COM to GND,
SHDN = VDD, fCLK = 100kHz, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
CONDITIONS MIN TYP MAX
SYMBOLPARAMETER
IN = COM (Note 4)
SHDN = GND
Operating mode, no load
0.5VSDL
SHDN Input Low 4.5VSDH
SHDN Input High
70PSRRPower-Supply Rejection Ratio 0.2 1ISHDN
Shutdown Current 1.2 1.5Supply Current IDD
4.5 5.5VDD
Supply Voltage
V
V
dB
µA
mA
V
UNITS
SHDN Input Leakage Current VSHDN = 0 to VDD ±0.2 ±10 µA
POWER REQUIREMENTS
SHUTDOWN
µA±0.1 ±10VOS = 0 to VDD
Input Leakage Current at OS µA±0.1 ±10
SHDN = GND, VCOM = 0 to VDD
Input Leakage Current at COM
Maximum Capacitive Output
Load Drive
UNITS
kHz
ppm/°C
V
mV
dB
dB
V/V
V
V
mVp-p
kΩ
pF
PARAMETER SYMBOL MIN TYP MAX
DC Insertion Gain with
Output Offset Removed -0.2 0 +0.2
Output Offset Voltage VOFFSET ±4 ±25
Output Voltage Range 0.25 VDD - 0.25
Clock-to-Corner Tempco 10
Total Harmonic Distortion
plus Noise THD+N -83
Offset Voltage Gain AOS 1
Corner Frequency fC0.001 to 15
Clock-to-Corner Ratio fCLK / fC100:1
COM Voltage Range VCOM 1.4 1.5 1.6
VCOM ±0.1
Clock Feedthrough 3
Resistance Output Load Drive RL10 1
CL50 500
CONDITIONS
VCOM = VDD / 2 (Note 2)
VIN = VCOM = VDD / 2
fIN = 200Hz, VIN = 2.5Vp-p,
measurement bandwidth = 22kHz
Input, COM externally driven
OS to OUT
Input, OS externally driven
(Note 1)
1.4 1.5 1.6
kΩInput Resistance at COM RCOM 110 180
Input Voltage Range at OS VOS
MAX7413
MAX7414 -81
FILTER CHARACTERISTICS
VOutput, COM unconnected
MAX7409/MAX7410/MAX7413/MAX7414
5th-Order, Lowpass,
Switched-Capacitor Filters
4 _______________________________________________________________________________________
COSC = 1000pF (Note 3)
CONDITIONS
21 30 38fOSC
Internal Oscillator Frequency
MIN TYP MAX
SYMBOLPARAMETER
IN = COM (Note 4)
SHDN = GND
Operating mode, no load
VCLK = 0 or 3V
0.5VSDL
SHDN Input Low 2.5VSDH
SHDN Input High
70PSRRPower-Supply Rejection Ratio 0.2 1ISHDN
Shutdown Current 1.2 1.5
2.7 3.6VDD
Supply Voltage
0.5VIL
Clock Input Low 2.5VIH
Clock Input High
±13.5 ±20ICLK
Clock Output Current
(Internal Oscillator Mode)
V
V
dB
µA
V
V
V
µA
kHz
UNITS
SHDN Input Leakage Current VSHDN= 0 to VDD 0.2 ±10 µA
FILTER CHARACTERISTICS
(VDD = +5V for MAX7409/MAX7410, VDD = +3V for MAX7413/MAX7414, filter output measured at OUT, 10kΩ|| 50pF load to GND at
OUT, SHDN = VDD, fCLK = 100kHz, TA = TMIN to TMAX, unless otherwise noted.)
Note 1: The maximum fCis defined as the clock frequency fCLK = 100 x fCat which the peak S / (THD+N) drops to 68dB with a
sinusoidal input at 0.2fC.
Note 2: DC insertion gain is defined as ∆VOUT / ∆VIN.
Note 3: fOSC (kHz) ≅ 30 x 103/ COSC (pF).
Note 4: PSRR is the change in output voltage from a VDD of 4.5V and a VDD of 5.5V.
CLOCK
POWER REQUIREMENTS
SHUTDOWN
CONDITIONS UNITS
MIN TYP MAX
PARAMETER
mAIDD
Supply Current
ELECTRICAL CHARACTERISTICS—MAX7413/MAX7414 (continued)
(VDD = +3V, filter output measured at OUT pin, 10kΩ|| 50pF load to GND at OUT, OS = COM, 0.1µF capacitor from COM to GND,
SHDN = VDD, fCLK = 100kHz, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
fIN = 0.5fC-1 -0.74
fIN = fC-3.6 -3.0 -2.4
fIN = 4fC-41.0 -35
fIN = 7fC
dB
-64.3 -58
fIN = 0.5fC
dB
-0.3 0
fIN = 3fC
fIN = fC-3.6 -3.0 -2.4
Insertion Gain Relative to
DC Gain -47.5 -43
fIN = 5fC-70 -65
Insertion Gain Relative to
DC Gain
BESSEL FILTERS—MAX7409/MAX7413
BUTTERWORTH FILTERS—MAX7410/MAX7414
MAX7409/MAX7410/MAX7413/MAX7414
5th-Order, Lowpass,
Switched-Capacitor Filters
_______________________________________________________________________________________ 5
-56
-40
-48
-32
-8
0
-16
-24
8
0 1.0 1.5 2.0 2.50.5 3.0 3.5 4.0 4.5 5.0
MAX7409/MAX7413
FREQUENCY RESPONSE
(BESSEL)
MAX7409 toc01
INPUT FREQUENCY (kHz)
GAIN (dB)
fC = 1kHz
-70
-50
-60
-40
-10
0
-20
-30
10
0 1.0 1.5 2.0 2.50.5 3.0 3.5 4.0 4.5 5.0
MAX7410/MAX7414
FREQUENCY RESPONSE
(BUTTERWORTH)
MAX7409 toc02
INPUT FREQUENCY (kHz)
GAIN (dB)
fC = 1kHz
-250
-200
-100
-150
-50
0
0 0.4 0.60.2 0.8 1.0 1.2 1.4 1.6
MAX7409/MAX7413
PHASE RESPONSE
(BESSEL)
MAX7409 toc05
INPUT FREQUENCY (kHz)
PHASE SHIFT (DEGREES)
fC = 1kHz
-350
-300
-200
-250
-100
-50
-150
0
0 0.4 0.60.2 0.8 1.0 1.2 1.4 1.6
MAX7410/MAX7414
PHASE RESPONSE
(BUTTERWORTH)
MAX7409 toc06
INPUT FREQUENCY (kHz)
PHASE SHIFT (DEGREES)
fC = 1kHz
-3.2
-2.4
-3.0
-2.0
-0.8
-0.4
-1.2
-1.6
0
0 204 306 408 510102 612 714 816 9181.02k
MAX7409/MAX7413
PASSBAND FREQUENCY RESPONSE
(BESSEL)
MAX7409 toc03
INPUT FREQUENCY (Hz)
GAIN (dB)
fC = 1kHz
-3.5
-2.5
-3.0
-2.0
-0.5
0
-1.0
-1.5
0.5
0 204 306 408 510102 612 714 816 9181.02k
MAX7410/MAX7414
PASSBAND FREQUENCY RESPONSE
(BUTTERWORTH)
MAX7409 toc04
INPUT FREQUENCY (Hz)
GAIN (dB)
fC = 1kHz
1.11
1.12
1.13
1.14
1.15
1.16
1.17
1.18
1.19
2.5 3.53.0 4.0 4.5 5.0 5.5
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX7409 toc07
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
Typical Operating Characteristics
(VDD = +5V for MAX7409/MAX7410, VDD = +3V for MAX7413/MAX7414, fCLK = 100kHz, SHDN = VDD, COM = OS = VDD / 2, TA= +25°C,
unless otherwise noted.)
LABEL fIN
(Hz) fC
(kHz)
A 200 1
B 1k 5
fCLK
(kHz)
100
500
MEASUREMENT
BANDWIDTH (kHz)
22
80
Table A. THD+N vs. Input Signal
Amplitude Plot Characteristics
MAX7409/MAX7410/MAX7413/MAX7414
5th-Order, Lowpass,
Switched-Capacitor Filters
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(VDD = +5V for MAX7409/MAX7410, VDD = +3V for MAX7413/MAX7414, fCLK = 100kHz, SHDN = VDD, COM = OS = VDD / 2, TA= +25°C,
unless otherwise noted.)
-90
-70
-80
-50
-60
-40
-30
-10
-20
0
0 1.0 2.0 3.0 4.0 5.00.5 1.5 2.5 3.5 4.5
MAX7409
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. INPUT SIGNAL AMPLITUDE
MAX7409 toc08
AMPLITUDE (Vp-p)
THD + NOISE (dB)
A
B
SEE TABLE A
-90
-70
-80
-50
-60
-40
-30
-10
-20
0
0 1.0 2.0 3.0 4.0 5.00.5 1.5 2.5 3.5 4.5
MAX7410
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. INPUT SIGNAL AMPLITUDE
MAX7409 toc09
AMPLITUDE (Vp-p)
THD + NOISE (dB)
A
B
SEE TABLE A
-90
-70
-80
-50
-60
-40
-30
-10
-20
0
0 0.5 1.0 1.5 2.0 2.5 3.0
MAX7413
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. INPUT SIGNAL AMPLITUDE
MAX7409 toc10
AMPLITUDE (Vp-p)
THD + NOISE (dB)
A
B
SEE TABLE A
-90
-70
-80
-50
-60
-40
-30
-10
-20
0
0 0.5 1.0 1.5 2.0 2.5 3.0
MAX7414
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. INPUT SIGNAL AMPLITUDE
MAX7409 toc11
AMPLITUDE (Vp-p)
THD + NOISE (dB)
A
B
SEE TABLE A
0
4
2
8
6
10
12
0 150 20050 100 250 300 350
INTERNAL OSCILLATOR PERIOD
vs. LARGE CAPACITANCE
MAX7409 toc14
CAPACITANCE (nF)
OSCILLATOR PERIOD (ms)
VDD = +5V
VDD = +3V
1.11
1.13
1.12
1.15
1.14
1.18
1.17
1.16
1.19
-40 0-20 20 40 60 80 100
SUPPLY CURRENT vs. TEMPERATURE
MAX7409 toc12
TEMPERATURE (°C)
SUPPLY CURENT (mA)
VDD = +5V
VDD = +3V
0
40
20
80
60
100
120
0 1500 2000500 1000 2500 3000 3500
INTERNAL OSCILLATOR PERIOD
vs. SMALL CAPACITANCE
MAX7409 toc13
CAPACITANCE (pF)
OSCILLATOR PERIOD (µs)
VDD = +5V
VDD = +3V
29.4
29.5
29.6
29.7
29.8
29.9
30.0
30.1
30.2
2.5 3.53.0 4.0 4.5 5.0 5.5
INTERNAL OSCILLATOR FREQUENCY
vs. SUPPLY VOLTAGE
MAX7409 toc15
SUPPLY VOLTAGE (V)
OSCILLATOR FREQUENCY (kHz)
COSC = 1000pF
29.0
29.5
30.5
30.0
31.0
31.5
-40 0-20 20 40 60 80 100
INTERNAL OSCILLATOR FREQUENCY
vs. TEMPERATURE
MAX7409 toc16
TEMPERATURE (°C)
OSCILLATOR FREQUENCY FREQUENCY (kHz)
VDD = +5V
VDD = +3V
COSC = 1000pF
MAX7409/MAX7410/MAX7413/MAX7414
5th-Order, Lowpass,
Switched-Capacitor Filters
_______________________________________________________________________________________ 7
NAME FUNCTION
1 COM Common Input Pin. Biased internally at midsupply. Bypass COM externally to GND with a 0.1µF capacitor.
To override internal biasing, drive COM with an external supply.
2 IN Filter Input
PIN
3 GND Ground
4 VDD Positive Supply Input: +5V for MAX7409/MAX7410, +3V for MAX7413/MAX7414.
8 CLK Clock Input. Connect an external capacitor (COSC) from CLK to ground: fOSC (kHz) = 30 x 103/ COSC (pF).
To override the internal oscillator, connect CLK to an external clock: fC= fCLK /100.
7SHDN Shutdown Input. Drive low to enable shutdown mode; drive high or connect to VDD for normal operation.
6 OS Offset Adjust Input. To adjust output offset, connect OS to an external supply through a resistive voltage-
divider (Figure 3). Connect OS to COM if no offset adjustment is needed. Refer to the
Offset and Common-
Mode Input Adjustment
section.
5 OUT Filter Output
Pin Description
_______________Detailed Description
The MAX7409/MAX7413 Bessel filters provide low over-
shoot and fast settling responses, and the MAX7410/
MAX7414 Butterworth filters provide a maximally flat
passband response. All parts operate with a 100:1
clock-to-corner frequency ratio and a 15kHz maximum
corner frequency.
Bessel Characteristics
Lowpass Bessel filters such as the MAX7409/MAX7413
delay all frequency components equally, preserving the
shape of step inputs (subject to the attenuation of the
higher frequencies). Bessel filters settle quickly—an
important characteristic in applications that use a multi-
plexer (mux) to select an input signal for 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.
Butterworth Characteristics
Lowpass Butterworth filters such as the MAX7410/
MAX7414 provide a maximally flat passband response,
making them ideal for instrumentation applications that
require minimum deviation from the DC gain throughout
the passband.
Typical Operating Characteristics (continued)
(VDD = +5V for MAX7409/MAX7410, VDD = +3V for MAX7413/MAX7414, fCLK = 100kHz, SHDN = VDD, COM = OS = VDD / 2, TA= +25°C,
unless otherwise noted.)
-4.50
-4.00
-4.25
-3.50
-3.75
-3.25
-3.00
-40 20 40-20 0 60 80 100
OUTPUT OFFSET VOLTAGE
vs. TEMPERATURE
MAX7409 toc17
TEMPERATURE (°C)
OFFSET VOLTAGE (mV)
VDD = +3V
VDD = +5V
-5.0
-4.0
-4.5
-3.0
-3.5
-2.5
-2.0
2.5 3.5 4.03.0 4.5 5.0 5.5
OUTPUT OFFSET VOLTAGE
vs. SUPPLY VOLTAGE
MAX7409 toc18
SUPPLY VOLTAGE (V)
DC OFFSET VOLTAGE (mV)
MAX7409/MAX7410/MAX7413/MAX7414
5th-Order, Lowpass,
Switched-Capacitor Filters
8 _______________________________________________________________________________________
The difference between Bessel and Butterworth filters
can be observed when a 1kHz square wave is applied
to the filter input (Figure 1, trace A). With the filter cutoff
frequencies set at 5kHz, trace B shows the Bessel filter
response and trace C shows the Butterworth filter
response.
Background Information
Most switched-capacitor filters (SCFs) are designed with
biquadratic sections. Each section implements two filter-
ing poles, and the sections are cascaded to produce
higher-order filters. The advantage to this approach is
ease of design. However, this type of design is highly
sensitive to component variations if any section’s Q is
high. An alternative approach is to emulate a passive net-
work using switched-capacitor integrators with summing
and scaling. Figure 2 shows a basic 5th-order ladder filter
structure.
A switched-capacitor filter such as the MAX7409/
MAX7410/MAX7413/MAX7414 emulates a passive ladder
filter. The filter’s component sensitivity is low when com-
pared to a cascaded biquad design, because each
component affects the entire filter shape, not just one
pole-zero pair. In other words, a mismatched component
in a biquad design will have a concentrated error on its
respective poles, while the same mismatch in a ladder
filter design results in an error distributed over all poles.
Clock Signal
External Clock
The MAX7409/MAX7410/MAX7413/MAX7414 family of
SCFs is designed for use with external clocks that have
a 50% ±10% duty cycle. When using an external clock
with these devices, drive CLK with a CMOS gate pow-
ered from 0 to VDD. Varying the rate of the external
clock adjusts the corner frequency of the filter as fol-
lows: fC= fCLK / 100
Internal Clock
When using the internal oscillator, connect a capacitor
(COSC) between CLK and ground. The value of the
capacitor determines the oscillator frequency as follows:
fOSC (kHz) = 30 x 103/ COSC (pF)
Minimize the stray capacitance at CLK so that it does
not affect the internal oscillator frequency. Vary the rate
of the internal oscillator to adjust the filter’s corner fre-
quency by a 100:1 clock-to-corner frequency ratio. For
example, an internal oscillator frequency of 100kHz
produces a nominal corner frequency of 1kHz.
Input Impedance vs. Clock Frequencies
The MAX7409/MAX7410/MAX7413/MAX7414’s input
impedance is effectively that of a switched-capacitor
resistor (see the following equation), and is inversely
proportional to frequency. The input impedance values
determined below represent the average input imped-
ance, since the input current is not continuous. As a
rule, use a driver with an output impedance less than
10% of the filter’s input impedance. Estimate the input
impedance of the filter using the following formula:
ZIN = 1 / ( fCLK x 2.1pF)
For example, an fCLK of 100kHz results in an input
impedance of 4.8MΩ.
Figure 2. 5th-Order Ladder Filter Network
Figure 1. Bessel vs. Butterworth Filter Response
MAX7409/MAX7410/MAX7413/MAX7414
5th-Order, Lowpass,
Switched-Capacitor Filters
_______________________________________________________________________________________ 9
Low-Power Shutdown Mode
These devices feature a shutdown mode that is activat-
ed by driving SHDN low. In shutdown mode, the filter’s
supply current reduces to 0.2µA and its output becomes
high impedance. For normal operation, drive SHDN
high or connect it to VDD.
__________Applications Information
Offset and Common-Mode
Input Adjustment
The COM pin sets the common-mode input voltage and
is biased at mid-supply with an internal resistor-divider.
If the application does not require offset adjustment,
connect OS to COM. For applications requiring offset
adjustment, apply an external bias voltage through a
resistor-divider network to OS such as shown in Fig-
ure 3. For applications that require DC level shifting,
adjust OS with respect to COM. (Note: OS should not
be left unconnected.) The output voltage is represent-
ed by this equation:
VOUT = (VIN - VCOM) + VOS
with VCOM = VDD / 2 (typical), and where (VIN - VCOM)
is lowpass filtered by the SCF, and OS is added at the
output stage. See the
Electrical Characteristics
for the
voltage range of COM and OS. Changing the voltage
on COM or OS significantly from midsupply reduces
the filter’s dynamic range.
Power Supplies
The MAX7409/MAX7410 operate from a single +5V
supply and the MAX7413/MAX7414 operate from a sin-
gle +3V supply. Bypass VDD to GND with a 0.1µF
capacitor. If dual supplies are required (±2.5V for
MAX7409/MAX7410, ±1.5V for MAX7413/MAX7414),
connect COM to system ground and connect GND to
the negative supply. Figure 4 shows an example of
dual-supply operation. Single- and dual-supply perfor-
mance are equivalent. For either single- or dual-supply
operation, drive CLK and SHDN from GND (V- in dual-
supply operation) to VDD. For ±5V dual-supply applica-
tions, use the MAX291–MAX297.
Input Signal Amplitude Range
The optimal input signal range is determined by
observing the voltage level at which the Total Harmonic
Distortion + Noise is minimized for a given corner fre-
quency. The
Typical Operating Characteristics
show
graphs of the devices’ Total Harmonic Distortion plus
Noise Response as the input signal’s peak-to-peak
amplitude is varied.
Anti-Aliasing and DAC Postfiltering
When using these devices for anti-aliasing or DAC
postfiltering, synchronize the DAC (or ADC) and the fil-
ter clocks. If the clocks are not synchronized, beat fre-
quencies will alias into the desired passband.
Harmonic Distortion
Harmonic distortion arises from nonlinearities within the
filter. These nonlinearities generate harmonics when a
pure sine wave is applied to the filter input. Table 1 lists
typical harmonic-distortion values for the MAX7410/
MAX7414 with a 10kΩload at TA= +25°C. Table 2 lists
typical harmonic-distortion values for the MAX7409/
MAX7413 with a 10kΩload at TA= +25°C.
Figure 3. Offset Adjustment Circuit
Figure 4. Dual-Supply Operation
MAX7409/MAX7410/MAX7413/MAX7414
5th-Order, Lowpass,
Switched-Capacitor Filters
10 ______________________________________________________________________________________
Table 2. MAX7409/MAX7413 Typical Harmonic Distortion
5th
3rd
-88.3
-87.9
-88.8
-86.9
-81
-85.4
-91.1-79
-87.9
-87.3
-86.4
-86
100
500 2
200
MAX7413 1k
100
500
fCLK
(kHz) 4th
2nd
-88.4
-88.8
TYPICAL HARMONIC DISTORTION (dB)
-83.5
-82.5
4
200
1k
MAX7409
VIN
(Vp-p)
fIN
(Hz)
FILTER
Table 1. MAX7410/MAX7414 Typical Harmonic Distortion
5th
3rd
-86.4
-87.6
-88.5
-85.5
-74
-78
-82-67
-85.8
-87.1
-86.1
-85.3
100
500 2
200
MAX7414 1k
100
500
fCLK
(kHz) 4th
2nd
-88.7
-86.7
TYPICAL HARMONIC DISTORTION (dB)
-84
-85
4
200
1k
MAX7410
VIN
(Vp-p)
fIN
(Hz)
FILTER
TRANSISTOR COUNT: 1457
Chip Information
Ordering Information (continued)
PART TEMP. RANGE PIN-PACKAGE
MAX7413CPA 0°C to +70°C 8 Plastic DIP
MAX7413EPA
MAX7414CUA
MAX7414CPA
MAX7414EUA -40°C to +85°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C 8 Plastic DIP
8 µMAX
8 Plastic DIP
8 µMAX
MAX7414EPA -40°C to +85°C 8 Plastic DIP
MAX7413CUA 0°C to +70°C 8 µMAX
MAX7413EUA -40°C to +85°C 8 µMAX
MAX7409/MAX7410/MAX7413/MAX7414
5th-Order, Lowpass,
Switched-Capacitor Filters
______________________________________________________________________________________ 11
________________________________________________________Package Information
8LUMAXD.EPS
MAX7409/MAX7410/MAX7413/MAX7414
5th-Order, Lowpass,
Switched-Capacitor Filters
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12
____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Package Information (continued)
PDIPN.EPS