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Part Number MAX7405

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For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
General Description
The MAX7401/MAX7405 8th-order, lowpass, Bessel,
switched-capacitor filters (SCFs) operate from a single
+5V (MAX7401) or +3V (MAX7405) supply. These
devices draw only 2mA of supply current and allow cor-
ner frequencies from 1Hz to 5kHz, making them ideal
for low-power post-DAC filtering and anti-aliasing appli-
cations. They feature a shutdown mode that reduces
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 MAX7401/MAX7405 Bessel filters provide low over-
shoot and fast settling. Their fixed response simplifies
the design task to selecting a clock frequency.
Applications
ADC Anti-Aliasing
CT2 Base Stations
Post-DAC Filtering
Speech Processing
Air-Bag Electronics
Features
o
8th-Order, Lowpass Bessel Filters
o
Low Noise and Distortion: -82dB THD + Noise
o
Clock-Tunable Corner Frequency (1Hz to 5kHz)
o
100:1 Clock-to-Corner Ratio
o
Single-Supply Operation
+5V (MAX7401)
+3V (MAX7405)
o
Low Power
2mA (Operating Mode)
0.2µA (Shutdown Mode)
o
Available in 8-Pin SO/DIP Packages
o
Low Output Offset: ±5mV
MAX7401/MAX7405
8th-Order, Lowpass, Bessel,
Switched-Capacitor Filters
________________________________________________________________
Maxim Integrated Products
1
OS
OUT
V
DD
1
2
8
7
CLK
SHDN
IN
GND
COM
SO/DIP
TOP VIEW
3
4
6
5
MAX7401
MAX7405
V
DD
IN
CLK
OUT
GND
INPUT
0.1
µ
F
0.1
µ
F
CLOCK
SHDN
OUTPUT
V
SUPPLY
COM
OS
MAX7401
MAX7405
Typical Operating Circuit
19-4788; Rev 1; 6/99
Pin Configuration
Ordering Information
PART
MAX7401CPA
MAX7401ESA
MAX7401EPA
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
TEMP. RANGE
PIN-PACKAGE
8 Plastic DIP
8 SO
8 Plastic DIP
MAX7405
CSA
MAX7405CPA
MAX7405ESA
MAX7405EPA
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
8 SO
8 Plastic DIP
8 SO
8 Plastic DIP
MAX7401
CSA
0°C to +70°C
8 SO
MAX7401/MAX7405
8th-Order, Lowpass, Bessel,
Switched-Capacitor Filters
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS--MAX7401
(V
DD
= +5V, filter output measured at OUT, 10k
|| 50pF load to GND at OUT, OS = COM, 0.1µF from COM to GND,
SHDN = V
DD
, f
CLK
= 100kHz, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +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.
V
DD
to GND
MAX7401 ..............................................................-0.3V to +6V
MAX7405 ..............................................................-0.3V to +4V
IN, OUT, COM, OS, CLK ...........................-0.3V to (V
DD
+ 0.3V)
SHDN........................................................................-0.3V to +6V
OUT Short-Circuit Duration...................................................1sec
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO (derate 5.88mW/°C above +70°C)................471mW
8-Pin DIP (derate 9.09mW/°C above +70°C) ...............727mW
Operating Temperature Ranges
MAX740 _C_A ....................................................0°C to +70°C
MAX740 _E_A .................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
C
OSC
= 1000pF (Note 4)
V
OS
= 0 to (V
DD
- 1V) (Note 3)
SHDN = GND, V
COM
= 0 to V
DD
(Note 1)
Input, COM externally driven
f
IN
= 200Hz, V
IN
= 4Vp-p,
measurement bandwidth = 22kHz
V
IN
= V
COM
= V
DD
/ 2
V
COM
= V
DD
/ 2 (Note 2)
CONDITIONS
29
38
48
f
OSC
Internal Oscillator Frequency
±0.1
±10
Input Leakage Current at OS
±0.1
±10
Input Leakage Current at COM
50
500
C
L
10
1
R
L
Resistive Output Load Drive
10
Clock Feedthrough
75
125
R
COM
Input Resistance at COM
100:1
f
CLK
/ f
C
Clock-to-Corner Ratio
0.001 to 5
f
C
Corner Frequency
V
COM
1
A
OS
OS Voltage Gain to OUT
-82
THD+N
Total Harmonic Distortion
plus Noise
10
Clock-to-Corner Tempco
0.25
V
DD -
0.25
Output Voltage Range
±5
±25
V
OFFSET
Output Offset Voltage
-0.1
0.15
0.3
DC Insertion Gain with
Output Offset Removed
MIN
TYP
MAX
SYMBOL
PARAMETER
V
CLK
= 0 or 5V
0.5
V
IL
Clock Input Low
V
DD
- 0.5
V
IH
Clock Input High
±15
±30
I
CLK
Clock Input Current
V
V
µA
kHz
µA
µA
pF
k
mVp-p
k
V
V/ V
dB
dB
mV
V
ppm/°C
kHz
UNITS
Maximum Capacitive Load at
OUT
COM Voltage Range
V
DD
/ 2
V
DD
/ 2
V
DD
/ 2
- 0.5
+ 0.5
V
COM
±0.1
V
OS
Input Voltage Range at OS
V
V
DD
/ 2
V
DD
/ 2
V
DD
/ 2
- 0.2
+ 0.2
FILTER CHARACTERISTICS
CLOCK
Output, COM internally biased
MAX7401/MAX7405
8th-Order, Lowpass, Bessel,
Switched-Capacitor Filters
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS--MAX7401 (continued)
(V
DD
= +5V, filter output measured at OUT, 10k
|| 50pF load to GND at OUT, OS = COM, 0.1µF from COM to GND,
SHDN = V
DD
, f
CLK
= 100kHz, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
ELECTRICAL CHARACTERISTICS--MAX7405
(V
DD
= +3V, filter output measured at OUT, 10k
|| 50pF load to GND at OUT, OS = COM, 0.1µF from COM to GND,
SHDN = V
DD
, f
CLK
= 100kHz, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
CONDITIONS
MIN
TYP
MAX
SYMBOL
PARAMETER
Measured at DC
SHDN = GND, CLK driven from 0 to V
DD
Operating mode, no load, IN = OS = COM
0.5
V
SDL
SHDN Input Low
V
DD
- 0.5
V
SDH
SHDN Input High
60
PSRR
Power-Supply Rejection Ratio
0.2
1
I
SHDN
Shutdown Current
2
3.5
Supply Current
I
DD
4.5
5.5
V
DD
Supply Voltage
V
V
dB
µA
mA
V
UNITS
SHDN Input Leakage Current
V
SHDN
= 0 to V
DD
±0.1
±10
µA
POWER REQUIREMENTS
SHUTDOWN
µA
±0.1
±10
V
OS
= 0 to (V
DD
- 1V) (Note 3)
Input Leakage Current at OS
µA
±0.1
±10
SHDN = GND, V
COM
= 0 to V
DD
Input Leakage Current at COM
Maximum Capacitive
Load at OUT
UNITS
kHz
ppm/°C
V
mV
dB
dB
V/ V
V
mVp-p
k
pF
PARAMETER
SYMBOL
MIN
TYP
MAX
DC Insertion Gain with
Output Offset Removed
-0.1
0.03
0.3
Output Offset Voltage
V
OFFSET
±5
±25
Output Voltage Range
0.25
V
DD -
0.25
Clock-to-Corner Tempco
10
Total Harmonic Distortion
plus Noise
THD+N
-84
OS Voltage Gain to OUT
A
OS
1
Corner Frequency
f
C
0.001 to 5
Clock-to-Corner Ratio
f
CLK/
f
C
100:1
COM Voltage Range
V
COM
V
DD
/ 2
V
DD
/ 2
V
DD
/ 2
- 0.1
+ 0.1
Clock Feedthrough
10
Resistance Output Load Drive
R
L
10
1
C
L
50
500
CONDITIONS
V
COM
= V
DD
/ 2 (Note 2)
V
IN
= V
COM
= V
DD
/ 2
f
IN
= 200Hz, V
IN
= 2.5Vp-p,
measurement bandwidth = 22kHz
(Note 1)
k
Input Resistance at COM
R
COM
75
125
COM internally biased or externally driven
V
Input Voltage Range at OS
V
OS
V
COM
±0.1
FILTER CHARACTERISTICS
MAX7401/MAX7405
8th-Order, Lowpass, Bessel,
Switched-Capacitor Filters
4
_______________________________________________________________________________________
C
OSC
= 1000pF (Note 4)
CONDITIONS
26
34
43
f
OSC
Internal Oscillator Frequency
MIN
TYP
MAX
SYMBOL
PARAMETER
Measured at DC
SHDN = GND, CLK driven from 0 to V
DD
Operating mode, no load, IN = OS = COM
V
CLK
= 0 or 3V
0.5
V
SDL
SHDN Input Low
V
DD
- 0.5
V
SDH
SHDN Input High
60
PSRR
Power-Supply Rejection Ratio
0.2
1
I
SHDN
Shutdown Current
2
3.5
2.7
3.6
V
DD
Supply Voltage
0.5
V
IL
Clock Input Low
V
DD
- 0.5
V
IH
Clock Input High
±15
±30
I
CLK
Clock Input Current
V
V
dB
µA
V
V
V
µA
kHz
UNITS
SHDN Input Leakage Current
V
SHDN
= 0 to V
DD
±0.1
±10
µA
FILTER CHARACTERISTICS--MAX7401/MAX7405
(V
DD
= +5V for MAX7401, V
DD
= +3V for MAX7405; filter output measured at OUT; 10k
||
50pF load to GND at OUT; SHDN = V
DD
;
V
COM =
V
OS =
V
DD
/2; f
CLK
= 100kHz; T
A
= T
MIN
to T
MAX
; unless otherwise noted. Typical values are at T
A
= +25°C.)
Note 1:
The maximum f
C
is defined as the clock frequency, f
CLK
= 100
·
f
C,
at which the peak SINAD drops to 68dB with a sinu-
soidal input at 0.2f
C
.
Note 2:
DC insertion gain is defined as
V
OUT
/
V
IN
.
Note 3:
OS voltages above V
DD
- 1V saturate the input and result in a 75µA typical input leakage current.
Note 4:
For MAX7401, f
OSC
(kHz)
38
·
10
3
/ C
OSC
(pF). For MAX7405, f
OSC
(kHz)
34
·
10
3
/ C
OSC
(pF).
CLOCK
POWER REQUIREMENTS
SHUTDOWN
CONDITIONS
UNITS
MIN
TYP
MAX
PARAMETER
mA
I
DD
Supply Current
ELECTRICAL CHARACTERISTICS--MAX7405 (continued)
(V
DD
= +3V, filter output measured at OUT, 10k
|| 50pF load to GND at OUT, OS = COM, 0.1µF from COM to GND,
SHDN = V
DD
, f
CLK
= 100kHz, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
f
IN
= 0.5f
C
-1.0
-0.8
-0.6
f
IN
= f
C
-3.3
-3.0
-2.7
f
IN
= 3f
C
-33
-29
f
IN
= 6f
C
dB
-79
-74
Insertion Gain Relative to
DC Gain
MAX7401/MAX7405
8th-Order, Lowpass, Bessel,
Switched-Capacitor Filters
_______________________________________________________________________________________
5
-70
-50
-60
-40
-10
0
-20
-30
10
0
1
2
3
4
5
FREQUENCY RESPONSE
MAX7401 toc01
INPUT FREQUENCY (kHz)
GAIN (dB)
f
C
= 1kHz
-3.5
-2.5
-3.0
-2.0
-0.5
0
-1.0
-1.5
0.5
0
202
404
606
808
1010
PASSBAND FREQUENCY RESPONSE
MAX7409 toc02
INPUT FREQUENCY (Hz)
GAIN (dB)
f
C
= 1kHz
1.97
1.99
1.98
2.01
2.00
2.02
2.03
-40
20
40
-20
0
60
80
100
SUPPLY CURRENT
vs. TEMPERATURE
MAX7401 toc05
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
NO LOAD
MAX7401
MAX7405
10,000
0.1
0.01
0.1
1
10
100
1000
INTERNAL OSCILLATOR FREQUENCY
vs. C
OSC
CAPACITANCE
1
MAX7401 toc08
C
OSC
CAPACITANCE (nF)
OSCILLATOR FREQUENCY (kHz)
10
100
1000
-20
-15
-10
-5
0
5
10
15
20
2.5
3.5
3.0
4.0
4.5
5.0
5.5
OFFSET VOLTAGE
vs. SUPPLY VOLTAGE
MAX7401 toc06
SUPPLY VOLTAGE (V)
OFFSET VOLTAGE (mV)
MAX7401
V
IN
= V
COM
= V
DD
/ 2
MAX7405
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
2.5
3.5
3.0
4.0
4.5
5.0
5.5
NORMALIZED OSCILLATOR FREQUENCY
vs. SUPPLY VOLTAGE
MAX7401 toc09
SUPPLY VOLTAGE (V)
NORMALIZED OSCILLATOR FREQUENCY
C
OSC
= 390pF
MAX7401
MAX7405
-400
-300
-350
-250
-100
-50
-150
-200
0
0
400
800
1200
1600
2000
PHASE RESPONSE
MAX7401 toc03
INPUT FREQUENCY (Hz)
PHASE SHIFT (DEGREES)
f
C
= 1kHz
1.5
1.8
1.7
1.6
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.5
3.5
3.0
4.0
4.5
5.0
5.5
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX7401 toc04
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
NO LOAD
MAX7405
MAX7401
-1.5
-1.0
0
-0.5
0.5
1.0
-40
0
-20
20
40
60
80
100
OFFSET VOLTAGE vs. TEMPERATURE
MAX7401 toc07
TEMPERATURE (°C)
OFFSET VOLTAGE (mV)
V
IN
= V
COM
= V
DD
/ 2
Typical Operating Characteristics
(V
DD
= +5V for MAX7401, V
DD
= +3V for MAX7405; f
CLK
= 100kHz; SHDN = V
DD
; V
COM
= V
OS
= V
DD
/ 2; T
A
= +25°C; unless otherwise
noted.)