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19-4766; Rev 1; 9/98
5th-Order, Lowpass, Switched-Capacitor Filters
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 0.2A. 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 output level. The MAX7409/MAX7413 Bessel filters provide low overshoot 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.
Features
o 5th-Order Lowpass Filters Bessel Response (MAX7409/MAX7413) Butterworth Response (MAX7410/MAX7414) o Clock-Tunable Corner Frequency (1Hz to 15kHz) o Single-Supply Operation +5V (MAX7409/MAX7410) +3V (MAX7413/MAX7414) o Low Power 1.2mA (operating mode) 0.2A (shutdown mode) o Available in 8-Pin MAX/DIP Packages o Low Output Offset: 4mV
MAX7409/MAX7410/MAX7413/MAX7414
Ordering Information
PART MAX7409CUA MAX7409CPA MAX7409EUA MAX7409EPA MAX7410CUA MAX7410CPA MAX7410EUA MAX7410EPA TEMP. RANGE 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C -40C to +85C -40C to +85C PIN-PACKAGE 8 MAX 8 Plastic DIP 8 MAX 8 Plastic DIP 8 MAX 8 Plastic DIP 8 MAX 8 Plastic DIP
Applications
ADC Anti-Aliasing DAC Postfiltering Air-Bag Electronics CT2 Base Stations Speech Processing
Selector Guide
PART MAX7409 MAX7410 MAX7413 MAX7414 FILTER RESPONSE Bessel Butterworth Bessel Butterworth OPERATING VOLTAGE (V) +5 +5 +3 +3
Ordering Information continued at end of data sheet.
Typical Operating Circuit
VSUPPLY
Pin Configuration
TOP VIEW
0.1F VDD INPUT IN SHDN OUT OUTPUT
COM IN GND
1 2 3
8 7
CLK SHDN OS OUT
CLOCK CLK
VDD 4
MAX7409 MAX7410 MAX7413 MAX7414
MAX/DIP
6 5
MAX7409 MAX7410 MAX7413 MAX7414
GND
COM OS 0.1F
________________________________________________________________ Maxim Integrated Products
1
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5th-Order, Lowpass, Switched-Capacitor Filters MAX7409/MAX7410/MAX7413/MAX7414
ABSOLUTE MAXIMUM RATINGS
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 = +70C) 8-Pin DIP (derate 9.09mW/C above +70C) ...............727mW 8-Pin MAX (derate 4.1mW/C above +70C) .............330mW Operating Temperature Ranges MAX74 _ _C_A ...................................................0C to +70C MAX74 _ _E_A ................................................-40C to +85C Storage Temperature Range .............................-65C to +160C Lead Temperature (soldering, 10sec) .............................+300C
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--MAX7409/MAX7410
(VDD = +5V, filter output measured at OUT, 10k || 50pF load to GND at OUT, OS = COM, 0.1F capacitor from COM to GND, SHDN = VDD, fCLK = 100kHz, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER FILTER CHARACTERISTICS Corner Frequency Clock-to-Corner Ratio Clock-to-Corner Tempco Output Voltage Range Output Offset Voltage DC Insertion Gain with Output Offset Removed Total Harmonic Distortion plus Noise Offset Voltage Gain COM Voltage Range Input Voltage Range at OS Input Resistance at COM Clock Feedthrough Resistive Output Load Drive Maximum Capacitive Output Load Drive Input Leakage Current at COM Input Leakage Current at OS CLOCK Internal Oscillator Frequency Clock Output Current (Internal Oscillator Mode) Clock Input High Clock Input Low fOSC ICLK VIH VIL COSC = 1000pF (Note 3) VCLK = 0 or 5V 4.5 0.5 21 30 13.5 38 20 kHz A V V RL CL SHDN = GND, VCOM = 0 to VDD VOS = 0 to VDD 10 50 THD+N AOS VCOM VOS RCOM VOFFSET VIN = VCOM = VDD / 2 VCOM = VDD / 2 (Note 2) fIN = 200Hz, VIN = 4Vp-p, measurement bandwidth = 22kHz OS to OUT Input, COM externally driven Output, COM unconnected Input, OS externally driven 110 2.0 2.3 MAX7409 MAX7410 -0.2 0.25 4 0 -85 -78 1 2.5 2.5 VCOM 0.1 180 5 1 500 0.1 0.1 10 10 3.0 2.7 fc fCLK / fc (Note 1) 0.001 to 15 100:1 10 VDD - 0.25 25 0.2 ppm/C V mV dB dB V/V V V k mVp-p k pF A A kHz SYMBOL CONDITIONS MIN TYP MAX UNITS
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5th-Order, Lowpass, Switched-Capacitor Filters
ELECTRICAL CHARACTERISTICS--MAX7409/MAX7410
(VDD = +5V, filter output measured at OUT, 10k || 50pF load to GND at OUT, OS = COM, 0.1F capacitor from COM to GND, SHDN = VDD, fCLK = 100kHz, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER POWER REQUIREMENTS Supply Voltage Supply Current Shutdown Current Power-Supply Rejection Ratio SHUTDOWN SHDN Input High SHDN Input Low SHDN Input Leakage Current VSDH VSDL V SHDN = 0 to VDD 0.2 4.5 0.5 10 V V A VDD IDD I SHDN PSRR Operating mode, no load SHDN = GND IN = COM (Note 4) 4.5 1.2 0.2 70 5.5 1.5 1 V mA A dB SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX7409/MAX7410/MAX7413/MAX7414
ELECTRICAL CHARACTERISTICS--MAX7413/MAX7414
(VDD = +3V, filter output measured at OUT pin, 10k || 50pF load to GND at OUT, OS = COM, 0.1F capacitor from COM to GND, SHDN = VDD, fCLK = 100kHz, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER FILTER CHARACTERISTICS Corner Frequency Clock-to-Corner Ratio Clock-to-Corner Tempco Output Voltage Range Output Offset Voltage DC Insertion Gain with Output Offset Removed Total Harmonic Distortion plus Noise Offset Voltage Gain COM Voltage Range Input Voltage Range at OS Input Resistance at COM Clock Feedthrough Resistance Output Load Drive Maximum Capacitive Output Load Drive Input Leakage Current at COM Input Leakage Current at OS RL CL SHDN = GND, VCOM = 0 to VDD VOS = 0 to VDD 10 50 THD+N AOS VCOM VOS RCOM VOFFSET VIN = VCOM = VDD / 2 VCOM = VDD / 2 (Note 2) fIN = 200Hz, VIN = 2.5Vp-p, measurement bandwidth = 22kHz OS to OUT Input, COM externally driven Output, COM unconnected Input, OS externally driven 110 1.4 1.4 MAX7413 MAX7414 -0.2 0.25 4 0 -83 -81 1 1.5 1.5 VCOM 0.1 180 3 1 500 0.1 0.1 10 10 1.6 1.6 fC fCLK / fC (Note 1) 0.001 to 15 100:1 10 VDD - 0.25 25 +0.2 ppm/C V mV dB dB V/V V V V k mVp-p k pF A A kHz SYMBOL CONDITIONS MIN TYP MAX UNITS
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5th-Order, Lowpass, Switched-Capacitor Filters MAX7409/MAX7410/MAX7413/MAX7414
ELECTRICAL CHARACTERISTICS--MAX7413/MAX7414 (continued)
(VDD = +3V, filter output measured at OUT pin, 10k || 50pF load to GND at OUT, OS = COM, 0.1F capacitor from COM to GND, SHDN = VDD, fCLK = 100kHz, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER CLOCK Internal Oscillator Frequency Clock Output Current (Internal Oscillator Mode) Clock Input High Clock Input Low POWER REQUIREMENTS Supply Voltage Supply Current Shutdown Current Power-Supply Rejection Ratio SHUTDOWN SHDN Input High SHDN Input Low SHDN Input Leakage Current VSDH VSDL V SHDN= 0 to VDD 0.2 2.5 0.5 10 V V A VDD IDD I SHDN PSRR Operating mode, no load SHDN = GND IN = COM (Note 4) 2.7 1.2 0.2 70 3.6 1.5 1 V mA A dB fOSC ICLK VIH VIL COSC = 1000pF (Note 3) VCLK = 0 or 3V 2.5 0.5 21 30 13.5 38 20 kHz A V V SYMBOL CONDITIONS MIN TYP MAX UNITS
FILTER CHARACTERISTICS
(VDD = +5V for MAX7409/MAX7410, VDD = +3V for MAX7413/MAX7414, filter output measured at OUT, 10k || 50pF load to GND at OUT, SHDN = VDD, fCLK = 100kHz, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER BESSEL FILTERS--MAX7409/MAX7413 fIN = 0.5fC Insertion Gain Relative to DC Gain fIN = fC fIN = 4fC fIN = 7fC BUTTERWORTH FILTERS--MAX7410/MAX7414 fIN = 0.5fC Insertion Gain Relative to DC Gain fIN = fC fIN = 3fC fIN = 5fC -0.3 -3.6 0 -3.0 -47.5 -70 -2.4 -43 -65 dB -1 -3.6 -0.74 -3.0 -41.0 -64.3 -2.4 -35 -58 dB CONDITIONS MIN TYP MAX UNITS
Note 1: The maximum fC is defined as the clock frequency fCLK = 100 x fC at 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.
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5th-Order, Lowpass, Switched-Capacitor Filters
Typical Operating Characteristics
(VDD = +5V for MAX7409/MAX7410, VDD = +3V for MAX7413/MAX7414, fCLK = 100kHz, SHDN = VDD, COM = OS = VDD / 2, TA = +25C, unless otherwise noted.)
MAX7409/MAX7413 FREQUENCY RESPONSE (BESSEL)
MAX7409 toc01
MAX7409/MAX7410/MAX7413/MAX7414
MAX7410/MAX7414 FREQUENCY RESPONSE (BUTTERWORTH)
MAX7409 toc02
MAX7409/MAX7413 PASSBAND FREQUENCY RESPONSE (BESSEL)
fC = 1kHz -0.4 -0.8 GAIN (dB) -1.2 -1.6 -2.0 -2.4 -3.0 -3.2
MAX7409 toc03
8 fC = 1kHz 0 -8 GAIN (dB)
10 fC = 1kHz 0 -10 GAIN (dB) -20 -30 -40 -50 -60 -70
0
-16 -24 -32 -40 -48 -56 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 INPUT FREQUENCY (kHz)
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 INPUT FREQUENCY (kHz)
0 102 204 306 408 510 612 714 816 918 1.02k INPUT FREQUENCY (Hz)
MAX7410/MAX7414 PASSBAND FREQUENCY RESPONSE (BUTTERWORTH)
fC = 1kHz 0 -0.5 GAIN (dB) -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 0 102 204 306 408 510 612 714 816 918 1.02k INPUT FREQUENCY (Hz) -250 0 0.2
MAX7409 toc04
MAX7409/MAX7413 PHASE RESPONSE (BESSEL)
MAX7409 toc05
MAX7410/MAX7414 PHASE RESPONSE (BUTTERWORTH)
fC = 1kHz -50 PHASE SHIFT (DEGREES) -100 -150 -200 -250 -300 -350
MAX7409 toc06
0.5
0 fC = 1kHz PHASE SHIFT (DEGREES) -50
0
-100
-150
-200
0.4
0.6
0.8
1.0
1.2
1.4
1.6
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
INPUT FREQUENCY (kHz)
INPUT FREQUENCY (kHz)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
1.18 SUPPLY CURRENT (mA) 1.17 1.16
MAX7409 toc07
1.19
Table A. THD+N vs. Input Signal Amplitude Plot Characteristics
LABEL A fIN (Hz) 200 1k fC (kHz) 1 5 fCLK (kHz) 100 500 MEASUREMENT BANDWIDTH (kHz) 22 80
1.15 1.14 1.13 1.12 1.11 2.5 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V)
B
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5th-Order, Lowpass, Switched-Capacitor Filters MAX7409/MAX7410/MAX7413/MAX7414
Typical Operating Characteristics (continued)
(VDD = +5V for MAX7409/MAX7410, VDD = +3V for MAX7413/MAX7414, fCLK = 100kHz, SHDN = VDD, COM = OS = VDD / 2, TA = +25C, unless otherwise noted.)
MAX7409 TOTAL HARMONIC DISTORTION PLUS NOISE vs. INPUT SIGNAL AMPLITUDE
MAX7409 toc08
MAX7410 TOTAL HARMONIC DISTORTION PLUS NOISE vs. INPUT SIGNAL AMPLITUDE
MAX7409 toc09
MAX7413 TOTAL HARMONIC DISTORTION PLUS NOISE vs. INPUT SIGNAL AMPLITUDE
SEE TABLE A -10 -20 THD + NOISE (dB) -30 -40 -50 -60 -70 -80 B A 0 0.5 1.0 1.5 2.0 2.5 3.0 AMPLITUDE (Vp-p)
MAX7409 toc10
0 SEE TABLE A -10 -20 THD + NOISE (dB) -30 -40 -50 -60 -70 -80 -90 0 A B
0 SEE TABLE A -10 -20 THD + NOISE (dB) -30 -40 -50 -60 -70 -80 -90 0 A B
0
-90 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 AMPLITUDE (Vp-p)
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 AMPLITUDE (Vp-p)
MAX7414 TOTAL HARMONIC DISTORTION PLUS NOISE vs. INPUT SIGNAL AMPLITUDE
MAX7409 toc11
SUPPLY CURRENT vs. TEMPERATURE
1.18 SUPPLY CURENT (mA) 1.17 1.16 1.15 1.14 1.13 1.12 VDD = +3V 0 -40 -20 0 20 40 60 80 100 0
MAX7409 toc12
INTERNAL OSCILLATOR PERIOD vs. SMALL CAPACITANCE
MAX7409 toc13
0 SEE TABLE A -10 -20 THD + NOISE (dB) -30 -40 -50 -60 -70 -80 -90 0 0.5 1.0 1.5 2.0 AMPLITUDE (Vp-p) A 2.5 B
1.19 VDD = +5V
120 100 OSCILLATOR PERIOD (s) VDD = +5V 80 60 40 20 VDD = +3V
1.11 3.0 TEMPERATURE (C)
500
1000 1500 2000 2500 3000 3500 CAPACITANCE (pF)
INTERNAL OSCILLATOR PERIOD vs. LARGE CAPACITANCE
MAX7409 toc14
INTERNAL OSCILLATOR FREQUENCY vs. SUPPLY VOLTAGE
MAX7409 toc15
INTERNAL OSCILLATOR FREQUENCY vs. TEMPERATURE
OSCILLATOR FREQUENCY FREQUENCY (kHz) COSC = 1000pF 31.0
MAX7409 toc16
12 10 OSCILLATOR PERIOD (ms) 8 VDD = +3V 6 4 2 0 0 50 100 150 200 250 300 VDD = +5V
30.2 30.1 OSCILLATOR FREQUENCY (kHz) 30.0 29.9 29.8 29.7 29.6 29.5 29.4 2.5 3.0 3.5 4.0 4.5 5.0 COSC = 1000pF
31.5
30.5
VDD = +3V
30.0
29.5
VDD = +5V
29.0 5.5 -40 -20 0 20 40 60 80 100 SUPPLY VOLTAGE (V) TEMPERATURE (C)
350
CAPACITANCE (nF)
6
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5th-Order, Lowpass, Switched-Capacitor Filters MAX7409/MAX7410/MAX7413/MAX7414
Typical Operating Characteristics (continued)
(VDD = +5V for MAX7409/MAX7410, VDD = +3V for MAX7413/MAX7414, fCLK = 100kHz, SHDN = VDD, COM = OS = VDD / 2, TA = +25C, unless otherwise noted.)
OUTPUT OFFSET VOLTAGE vs. TEMPERATURE
MAX7409 toc17
OUTPUT OFFSET VOLTAGE vs. SUPPLY VOLTAGE
MAX7409 toc18
-3.00 -3.25 OFFSET VOLTAGE (mV) -3.50 -3.75 VDD = +5V -4.00 -4.25 -4.50 -40 -20 0 20 40 60 80 VDD = +3V
-2.0 -2.5 DC OFFSET VOLTAGE (mV) -3.0 -3.5 -4.0 -4.5 -5.0
100
2.5
3.0
3.5
4.0
4.5
5.0
5.5
TEMPERATURE (C)
SUPPLY VOLTAGE (V)
Pin Description
PIN 1 2 3 4 5 6 7 8 NAME COM IN GND VDD OUT OS SHDN CLK FUNCTION Common Input Pin. Biased internally at midsupply. Bypass COM externally to GND with a 0.1F capacitor. To override internal biasing, drive COM with an external supply. Filter Input Ground Positive Supply Input: +5V for MAX7409/MAX7410, +3V for MAX7413/MAX7414. Filter Output Offset Adjust Input. To adjust output offset, connect OS to an external supply through a resistive voltagedivider (Figure 3). Connect OS to COM if no offset adjustment is needed. Refer to the Offset and CommonMode Input Adjustment section. Shutdown Input. Drive low to enable shutdown mode; drive high or connect to VDD for normal operation. 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.
_______________Detailed Description
The MAX7409/MAX7413 Bessel filters provide low overshoot 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.
higher frequencies). Bessel filters settle quickly--an important characteristic in applications that use a multiplexer (mux) to select an input signal for an analog-todigital 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.
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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
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5th-Order, Lowpass, Switched-Capacitor Filters MAX7409/MAX7410/MAX7413/MAX7414
RS 2V/div A 2V/div B 2V/div C + C1 L2 C3 L4 C5
VIN
RL
Figure 2. 5th-Order Ladder Filter Network
Clock Signal
200s/div A: 1kHz INPUT SIGNAL B: MAX7409 BESSEL FILTER RESPONSE; fC = 5kHz C: MAX7410 BUTTERWORTH FILTER RESPONSE; fC = 5kHz
Figure 1. Bessel vs. Butterworth Filter Response
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 powered from 0 to VDD. Varying the rate of the external clock adjusts the corner frequency of the filter as follows:
fC = fCLK / 100
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.
Internal Clock When using the internal oscillator, connect a capacitor (C OSC) 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 frequency by a 100:1 clock-to-corner frequency ratio. For example, an internal oscillator frequency of 100kHz produces a nominal corner frequency of 1kHz.
Background Information
Most switched-capacitor filters (SCFs) are designed with biquadratic sections. Each section implements two filtering 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 network 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 compared 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.
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 impedance, 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 4.8M.
8
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5th-Order, Lowpass, Switched-Capacitor Filters
Low-Power Shutdown Mode
These devices feature a shutdown mode that is activated by driving SHDN low. In shutdown mode, the filter's supply current reduces to 0.2A and its output becomes high impedance. For normal operation, drive SHDN high or connect it to VDD.
MAX7409/MAX7410/MAX7413/MAX7414
VSUPPLY
0.1F VDD INPUT IN SHDN OUT COM 0.1F 50k
OUTPUT
__________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 Figure 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 represented 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.
CLOCK
CLK
MAX7409 MAX7410 MAX7413 MAX7414
GND
OS 0.1F
50k
50k
Figure 3. Offset Adjustment Circuit
V+
VDD INPUT IN
SHDN OUT COM
* OUTPUT
V+ V-
CLOCK
CLK
Power Supplies
The MAX7409/MAX7410 operate from a single +5V supply and the MAX7413/MAX7414 operate from a single +3V supply. Bypass V DD to GND with a 0.1F 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 performance are equivalent. For either single- or dual-supply operation, drive CLK and SHDN from GND (V- in dualsupply operation) to VDD. For 5V dual-supply applications, use the MAX291-MAX297.
MAX7409 MAX7410 MAX7413 MAX7414
GND
OS 0.1F 0.1F
V*DRIVE SHDN TO V- FOR LOW-POWER SHUTDOWN MODE.
Figure 4. Dual-Supply Operation
Anti-Aliasing and DAC Postfiltering
When using these devices for anti-aliasing or DAC postfiltering, synchronize the DAC (or ADC) and the filter clocks. If the clocks are not synchronized, beat frequencies will alias into the desired passband.
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 frequency. 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.
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 10k load at TA = +25C. Table 2 lists typical harmonic-distortion values for the MAX7409/ MAX7413 with a 10k load at TA = +25C.
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5th-Order, Lowpass, Switched-Capacitor Filters MAX7409/MAX7410/MAX7413/MAX7414
Table 1. MAX7410/MAX7414 Typical Harmonic Distortion
FILTER fCLK (kHz) 500 MAX7410 100 500 MAX7414 100 200 200 1k 2 -86.1 -85.5 -85.8 -86.4 fIN (Hz) 1k 4 -84 -85.3 -78 -74 -88.7 -87.1 -88.5 -87.6 VIN (Vp-p) TYPICAL HARMONIC DISTORTION (dB) 2nd -85 3rd -67 4th -86.7 5th -82
Table 2. MAX7409/MAX7413 Typical Harmonic Distortion
FILTER fCLK (kHz) 500 MAX7409 100 500 MAX7413 100 200 200 1k 2 -86.4 -86.9 -87.9 -88.3 fIN (Hz) 1k 4 -83.5 -86 -85.4 -81 -88.4 -87.3 -88.8 -87.9 VIN (Vp-p) TYPICAL HARMONIC DISTORTION (dB) 2nd -82.5 3rd -79 4th -88.8 5th -91.1
Ordering Information (continued)
PART MAX7413CUA MAX7413CPA MAX7413EUA MAX7413EPA MAX7414CUA MAX7414CPA MAX7414EUA MAX7414EPA TEMP. RANGE 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C -40C to +85C -40C to +85C PIN-PACKAGE 8 MAX 8 Plastic DIP 8 MAX 8 Plastic DIP 8 MAX 8 Plastic DIP 8 MAX 8 Plastic DIP
Chip Information
TRANSISTOR COUNT: 1457
10
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5th-Order, Lowpass, Switched-Capacitor Filters
________________________________________________________Package Information
8LUMAXD.EPS
MAX7409/MAX7410/MAX7413/MAX7414
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11
5th-Order, Lowpass, Switched-Capacitor Filters MAX7409/MAX7410/MAX7413/MAX7414
Package Information (continued)
PDIPN.EPS
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 (c) 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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