LINER LTC1062MJ8 5th order lowpass filter Datasheet

LTC1062
5th Order Lowpass Filter
U
FEATURES
■
■
■
■
■
■
■
■
■
DESCRIPTIO
Lowpass Filter with No DC Error
Low Passband Noise
Operates DC to 20kHz
Operates On a Single 5V Supply or Up to ±8V
5th Order Filter
Maximally Flat Response
Internal or External Clock
Cascadable for Faster Rolloff
Buffer Available
U
APPLICATIO S
■
■
■
■
■
■
■
60Hz Lowpass Filters
Antialiasing Filter
Low Level Filtering
Rolling Off AC Signals from High DC Voltages
Digital Voltmeters
Scales
Strain Gauges
The LTC®1062 is a 5th order all pole maximally flat
lowpass filter with no DC error. Its unusual architecture
puts the filter outside the DC path so DC offset and low
frequency noise problems are eliminated. This makes the
LTC1062 very useful for lowpass filters where DC accuracy
is important.
The filter input and output are simultaneously taken across
an external resistor. The LTC1062 is coupled to the signal
through an external capacitor. This RC reacts with the
internal switched capacitor network to form a 5th order
rolloff at the output.
The filter cutoff frequency is set by an internal clock that
can be externally driven. The clock-to-cutoff frequency
ratio is typically 100:1, allowing the clock ripple to be
easily removed.
Two LTC1062s can be cascaded to form a 10th order quasi
max flat lowpass filter. The device can be operated with
single or dual supplies ranging from ±2.5V to ±9V.
The LTC1062 is manufactured using Linear Technology’s
enhanced LTCMOSTM silicon gate process.
, LTC and LT are registered trademarks of Linear Technology Corporation.
LTCMOS is a trademark of Linear Technology Corporation.
U
TYPICAL APPLICATIO
10Hz 5th Order Butterworth Lowpass Filter
25.8k
BOUT
AGND
OUT
8
BUFFERED
OUTPUT
7
LTC1062
V – = –5V
3
4
V–
V+
DIVIDER COSC
RATIO
6
5
COSC=
3900pF
V + = 5V
1062 TA01
AMPLITUDE RESPONSE (dB)
FB
COSC = 3900pF
–10
–20
–30
–40
–50
50
–60
40
–70
30
–80
20
–90
10
–100
1
NOTE: TO ADJUST OSCILLATOR FREQUENCY,
USE A 6800pF CAPACITOR IN SERIES
WITH A 50k POT FROM PIN 5 TO GROUND
10
INPUT FREQUENCY (Hz)
FILTER OUTPUT NOISE (µV/√Hz)
1µF
2
0
DC ACCURATE
OUTPUT
VIN
1
Filter Amplitude Response and Noise
0
100
1062 TA02
1062fd
1
LTC1062
W W
W
AXI U
U
ABSOLUTE
RATI GS
(Note 1)
Total Supply Voltage (V+ to V–) ............................... 18V
Input Voltage at Any Pin ..... V– – 0.3V ≤ VIN ≤ V+ + 0.3V
Operating Temperature Range
LTC1062M (OBSOLETE) ............. –55°C ≤ TA ≤ 125°C
LTC1062C ................................... – 40°C ≤ TA ≤ 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
U
U
W
PACKAGE/ORDER I FOR ATIO
TOP VIEW
FB 1
8
BOUT
AGND 2
7
OUT
V– 3
6
V+
DIVIDER 4
RATIO
5
COSC
ORDER PART
NUMBER
LTC1062CN8
16 NC
NC 2
15 NC
FB 3
14 BOUT
LTC1062MJ8
LTC1062CJ8
LTC1062CSW
13 OUT
12 V +
V– 5
DIVIDER
6
RATIO
NC 7
TJ MAX = 100°C, θJA = 130°C/W
J8 PACKAGE 8-LEAD CERDIP
TJ MAX = 150°C, θJA = 100°C/W
NC 1
AGND 4
N8 PACKAGE
8-LEAD PDIP
ORDER PART
NUMBER
TOP VIEW
11 COSC
10 NC
NC 8
9
NC
SW PACKAGE
16-LEAD PLASTIC SO
TJ MAX = 150°C, θJA = 90°C/W
OBSOLETE PACKAGE
Consider the N8 Package as an Alternate Source
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS+
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V = 5V, V– = – 5V, unless otherwise specified. AC output measured at Pin 7,
Figure 1.
PARAMETER
Power Supply Current
CONDITIONS
COSC
MIN
(Pin 5 to V –, Pin 11 in SW16) = 100pF
TYP
MAX
4.5
7
10
●
Input Frequency Range
0 to 20
= 100kHz, Pin 4 (Pin 6 in SW16) at V+,
Filter Gain at fIN = 0
fIN = 0.5fC (Note 2)
fIN = fC
fIN = 2fC
fIN = 4fC
fCLK
C = 0.01µF, R = 25.78k
Clock-to-Cutoff Frequency Ratio, fCLK/fC
fCLK = 100kHz, Pin 4 (Pin 6 in SW16) at V+,
C = 0.01µF, R = 25.78k
Filter Gain at fIN = 16kHz
fCLK = 400kHz, Pin 4 at V +, C = 0.01µF, R = 6.5k
fCLK/fC Tempco
fCLK = 400kHz, Pin 4 at V+, C = 0.01µF, R = 6.5k
Filter Output (Pin 7, Pin 13 in SW16) DC Swing
Pin 7/Pin13 (SW16) Buffered with an External Op Amp
Clock Feedthrough
●
●
●
●
●
–2
–28
–52
–43
±3.5
UNITS
mA
mA
kHz
0.00
– 0.02 –0.3
–3.00
–30.00
–60.00
dB
dB
dB
dB
dB
100 ±1
%
–52
dB
10
ppm/°C
±3.8
1
V
mVP-P
1062fd
2
LTC1062
ELECTRICAL CHARACTERISTICS+
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V = 5V, V– = – 5V, unless otherwise specified, AC output measured at Pin 7,
Figure 1.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
2
170
50
1000
pA
pA
2
20
mV
Internal Buffer
Bias Current
●
Offset Voltage
Voltage Swing
RLOAD = 20k
●
±3.5
Short-Circuit Current Source/Sink
±3.8
V
40/3
mA
Clock (Note 3)
COSC (Pin 5 to V–, Pin 11 in SW16) = 100pF
Internal Oscillator Frequency
25
15
●
32
Max Clock Frequency
50
65
kHz
kHz
4
Pin 5 (Pin 11 in SW16) Source or Sink Current
40
●
Note 1: Absolute Maximum Ratings are those values beyond which the life of
a device may be impaired.
Note 2: fC is the frequency where the gain is –3dB with respect to the input
signal.
MHz
80
µA
Note 3: The external or driven clock frequency is divided by either 1, 2 or 4
depending upon the voltage at Pin 4. For the N8 package, when Pin 4 = V +,
ratio = 1; when Pin 4 = GND, ratio = 2; when Pin 4 = V –, ratio = 4.
U W
TYPICAL PERFOR A CE CHARACTERISTICS
0
–10
0
VS = ±2.5V
TA = 25°C
1 = fC
2πRC 1.62
–10
–20
–30
–40
–50
–60
RESPONSE (dB)
RESPONSE (dB)
–20
Amplitude Response Normalized
to the Cutoff Frequency
fCLK = 500kHz, fC = 5kHz
fCLK = 250kHz, fC = 2.5kHz
fCLK = 100kHz, fC = 1kHz
–90
–100
0.1
0.4
VS = ±2.5V
TA = 25°C
1 = fC
2πRC 1.62
VS = ±5V
TA = 25°C
0.2 f
CLK = 100kHz
–30
–40
–50
–60
fCLK = 500kHz, fC = 5kHz
fCLK = 250kHz, fC = 2.5kHz
fCLK = 100kHz, fC = 1kHz
–70
–70
–80
Passband Gain
vs Input Frequency
PASSBAND GAIN (dB)
Amplitude Response Normalized
to the Cutoff Frequency
–80
fCLK = 10kHz, fC = 100Hz
–90
fCLK = 1kHz, fC = 10Hz
1
fIN/fC
10
1062 G01
–100
0.1
1 = fC
2πRC 1.6
0
–0.2
1 = fC
2πRC 1.62
–0.4
1 = fC
2πRC 1.64
–0.6
fCLK = 10kHz, fC = 100Hz
–0.8
fCLK = 1kHz, fC = 10Hz
1
fIN/fC
10
–1.0
0.1
0.2
0.4
0.6
0.8
1
fIN/fC
1062 G01
1062 G03
1062fd
3
LTC1062
U W
TYPICAL PERFOR A CE CHARACTERISTICS
0
TA = –55°C
–0.2
VS = ±5V
fCLK = 100kHz
1 = fC
2πRC 1.62
TA = 25°C
–30
TA = 125°C
–0.4
–0.6
–60
–90
–120
–150
–0.8
–180
–1.0
0.1
–210
0.1
0.2
0.4
0.6
0.8
1
Filter Noise Spectral Density
0.2
0.4
0.6
1.5
240
OSCILLATOR FREQUENCY (kHz)
OSCILLATOR FREQUENCY NORMALIZED
TO fOSC AT 5V SUPPLY
260
1.4
1.3
1.2
1.1
1.0
0.9
0.8
12
14
VSUPPLY (V)
30
20
fC = 100Hz
0.8
fC = 1kHz
0
0.1
1
1
16
18
20
1062 G07
1k
10
100
CUTOFF FREQUENCY (Hz)
Power Supply Current
vs Power Supply Voltage
16
COSC = 0pF
14
200
180
160
V + = 10V
– = 0V
V
140
120
100
10k
1062 G06
220
80
10
fC = 10Hz
40
Oscillator Frequency, fOSC
vs Ambient Temperature
1.6
8
50
1062 G05
Normalized Oscillator Frequency,
fOSC vs Supply Voltage
6
60
fIN/fC
1062 G04
4
VS = ±5V
TA = 25°C
70
10
fIN/fC
0.7
80
SUPPLY CURRENT (mA)
VS = ±5V
fCLK = 100kHz
1 = fC
2πRC 1.62
0.2
PASSBAND GAIN (dB)
0
PHASE SHIFT (DEG)
0.4
Passband Phase Shift
vs Input Frequency
FILTER OUTPUT NOISE (µV/√Hz)
Passband Gain
vs Input Frequency and Temperature
V + = 5V
–
V = 0V
TA = –55°C
12
TA = 25°C
10
8
6
TA = 125°C
4
2
60
25 50
–50 –25
0
75 100
AMBIENT TEMPERATURE (°C)
0
125
1062 G08
4
6
8
10 12 14 16 18
POWER SUPPLY VOLTAGE (V)
20
1062 G09
1062fd
4
LTC1062
W
BLOCK DIAGRA
For Adjusting Oscillator Frequency, Insert a 50k Pot in Series with COSC. Use Two Times Calculated COSC
FB
1
AGND
2
SWITCHED
CAPACITOR
NETWORK
BY CONNECTING PIN 4 TO V +, AGND OR V –, THE
OUTPUT FREQUENCY OF THE INTERNAL CLOCK
GENERATOR IS THE OSCILLATOR FREQUENCY DIVIDED BY 1, 2, 4. THE (fCLK/fC) RATIO OF 100:1 IS
WITH RESPECT TO THE INTERNAL CLOCK GENERATOR OUTPUT FREQUENCY. PIN 5 CAN BE DRIVEN
WITH AN EXTERNAL CMOS LEVEL CLOCK. THE
LTC1062 CAN ALSO BE SELF-CLOCKED BY CONNECTING AN EXTERNAL CAPACITOR (COSC) TO
GROUND (OR TO V – IF COSC IS POLARIZED). UNDER
THIS CONDITION AND WITH ±5V SUPPLIES, THE
INTERNAL OSCILLATOR FREQUENCY IS:
8 BOUT
×1
7 OUT
fCLK
V–
3
CLOCK GEN
÷
4
÷ 1, 2, 4
6 V+
OSC
5 COSC
fOSC ≅ 140kHz [33pF/(33pF + COSC)]
1062 BD
AC TEST CIRCUIT
5V
VIN
R = 25.8k
3
50Ω
1
2
FB
OUT
8
2
7
V
3
4
V–
V+
DIVIDER COSC
RATIO
–
MEASURED
OUTPUT
0.1µF
5V
R′
FOR BEST MAX FLAT APPROXIMATION,
THE INPUT RC SHOULD BE SUCH AS:
1 = fCLK
1
•
2πRC 100
1.63
4
0.1µF
6
5
8
1
LTC1062
– = –5V
6
LTC1052
BOUT
AGND
7
+
C = 0.01µF
A 0.5k RESISTOR, R′, SHOULD BE USED IF
THE BIPOLAR EXTERNAL CLOCK IS APPLIED
BEFORE THE POWER SUPPLIES TURN ON
–5V
–5V
1062 F01
fCLK = 100kHz
5V
Figure 1
1062fd
5
LTC1062
U
W
U U
APPLICATIO S I FOR ATIO
Filter Input Voltage Range
Every node of the LTC1062 typically swings within 1V of
either voltage supply, positive or negative. With the appropriate external (RC) values, the amplitude response of all
the internal or external nodes does not exceed a gain of
0dB with the exception of Pin 1. The amplitude response
of the feedback node (Pin 1) is shown in Figure 2. For an
input frequency around 0.8 • fC, the gain is 1.7V/V and, with
±5V supplies, the peak-to-peak input voltage should not
exceed 4.7V. If the input voltage goes beyond this value,
clipping and distortion of the output waveform occur, but
the filter will not get damaged nor will it oscillate. Also, the
absolute maximum input voltage should not exceed the
power supplies.
6
VS = ±5V
1 = fC
2πRC 1.62
4
2
VPIN1/VIN (dB)
0
–2
–4
–6
–8
–10
–12
–14
0.1
1
fIN/fC
10
1062 F02
Figure 2. Amplitude Response of Pin 1
Internal Buffer
The internal buffer out (Pin 8) and Pin 1 are part of the
signal AC path. Excessive capacitive loading will cause
gain errors in the passband, especially around the cutoff
frequency. The internal buffer gain at DC is typically
0.006dB. The internal buffer output can be used as a filter
output, however, it has a few millivolts of DC offset. The
temperature coefficient of the internal buffer is typically
1µV/°C.
Filter Attenuation
The LTC1062 rolloff is typically 30dB/octave. When the
clock and the cutoff frequencies increase, the filter’s
maximum attenuation decreases. This is shown in the
Typical Performance Characteristics. The decrease of the
maximum attenuation is due to the rolloff at higher
frequencies of the loop gains of the various internal
feedback paths and not to the increase of the noise floor.
For instance, for a 100kHz clock and 1kHz cutoff frequency, the maximum attenuation is about 64dB. A 4kHz,
1VRMS input signal will be predictably attenuated by 60dB
at the output. A 6kHz, 1VRMS input signal will be attenuated by 64dB and not by 77dB as an ideal 5th order
maximum flat filter would have dictated. The LTC1062
output at 6kHz will be about 630µVRMS. The measured
RMS noise from DC to 17kHz was 100µVRMS which is
16dB below the filter output.
COSC, Pin 5
The COSC, Pin 5, can be used with an external capacitor,
COSC, connected from Pin 5 to ground. If COSC is polarized
it should be connected from Pin 5 to the negative supply,
Pin 3. COSC lowers the internal oscillator frequency. If
Pin 5 is floating, an internal 33pF capacitor plus the
external interpin capacitance set the oscillator frequency
around 140kHz with ±5V supply. An external COSC will
bring the oscillator frequency down by the ratio (33pF)/
(33pF + COSC). The Typical Performance Characteristics
curves provide the necessary information to get the internal oscillator frequency for various power supply ranges.
Pin 5 can also be driven with an external CMOS clock to
override the internal oscillator. Although standard 7400
series CMOS gates do not guarantee CMOS levels with the
current source and sink requirements of Pin 5, they will, in
reality, drive the COSC pin. CMOS gates conforming to
standard B series output drive have the appropriate voltage levels and more than enough output current to
simultaneously drive several LTC1062 COSC pins. The
typical trip levels of the internal Schmitt trigger which
input is Pin 5, are given in Table 1.
Table 1
VSUPPLY
VTH+
VTH–
±2.5V
0.9V
–1V
±5V
1.3V
–2.1V
±6V
1.7V
–2.5V
±7V
1.75V
–2.9V
1062fd
6
LTC1062
U
W
U U
APPLICATIO S I FOR ATIO
Divide By 1, 2, 4 (Pin 4)
Filter Noise
By connecting Pin 4 to V+, to mid supplies or to V–, the
clock frequency driving the internal switched capacitor
network is the oscillator frequency divided by 1, 2, 4
respectively. Note that the fCLK/fC ratio of 100:1 is with
respect to the internal clock generator output frequency.
The internal divider is useful for applications where octave
tuning is required. The ÷2 threshold is typically ±1V from
the mid supply voltage.
The filter wideband RMS noise is typically 100µVRMS for
±5V supply and it is nearly independent from the value of
the cutoff frequency. For single 5V supply the RMS noise
is 80µVRMS. Sixty-two percent of the wideband noise is in
the passband, that is from DC to fC. The noise spectral
density, unlike conventional active filters, is nearly zero for
frequencies below 0.1 • fC. This is shown in the Typical
Performance Characteristics section. Table 2 shows the
LTC1062 RMS noise for different noise bandwidths.
Transient Response
Figure 3 shows the LTC1062 response to a 1V input step.
200mV/VERT DIV
50ms/HORIZ DIV, fC = 10Hz
5ms/HORIZ DIV, fC = 100Hz
0.5ms/HORIZ DIV, fC = 1kHz
f
1
= C
2πRC 1.94
f
1
= C
2πRC 1.62
f
1
= C
2πRC 2.11
Figure 3. Step Response to a 1V Peak Input Step
Table 2
NOISE BW
RMS NOISE (VS = ±5V)
DC – 0.1 • fC
2µV
DC – 0.25 • fC
8µV
DC – 0.5 • fC
20µV
DC – 1 • fC
62µV
DC – 2 • fC
100µV
1062fd
7
LTC1062
U
TYPICAL APPLICATIO S
AC Coupling an External CMOS Clock Powered
from a Single Positive Supply, V +
VOUT
VIN
C
1
2
FB
BOUT
AGND
OUT
8
7
LTC1062
V–
3
4
V–
V+
DIVIDER COSC
RATIO
6
V + 0.01µF
V+
5
0
100k
1062 TA03
Adding an External (R1, C1) to Eliminate the Clock Feedthrough and
to Improve the High Frequency Attenuation Floor
–
EXTERNAL
BUFFER
R1
10R
R
VOUT
+
VIN
C
1
2
FB
BOUT
AGND
OUT
C1
0.01C
8
7
LTC1062
V–
3
4
V–
V+
DIVIDER COSC
RATIO
6
5
V+
fCLK
1062 TA04
Filtering AC Signals from High DC Voltages
Passband Amplitude Response for the
High DC Accurate 5th Order Filter
0.2
R
25.8k
C
0.01µF
1
HIGH DC INPUT = 100V
2
FB
C
0.01µF
BOUT
AGND
OUT
8
7
12R
309.6k
LTC1062
V
– = –5V
3
4
V–
6
V+
DIVIDER COSC
RATIO
5
0
DC OUTPUT
CLK IN = fC • 100
1062 TA05
V + = 5V
EXAMPLE:
fCLK = 100KHz, fC = 1kHz. THE FILTER ACCURATELY PASSES
THE HIGH DC INPUT AND ACTS AS 5TH ORDER LP FILTER
FOR THE AC SIGNALS RIDING ON THE DC
PASSBAND GAIN (dB)
VIN
–0.2
–0.4
–0.6
–0.8
–1.0
–1.2 VS = ±5V
fCLK = 100kHz
–1.4
0.01
0.1
fIN /fC
1
1062 TA06
1062fd
8
LTC1062
U
TYPICAL APPLICATIO S
Cascading Two LTC1062s to Form a Very
Selective Clock Sweepable Bandpass Filter
R1
10k
R′1
10k
VIN
R2
10k 1
2
FB
BOUT
OUT
AGND
8
R′2
12.5k 1
7
2
FB
AGND
LTC1062
–5V
3
4
V
–
BOUT
OUT
8
VOUT
7
LTC1062
V
+
DIVIDER COSC
RATIO
6
5V
3
–5V
5
V
4
–
V+
DIVIDER COSC
RATIO
6
5V
5
fCLK
1062 TA07
Clock Tunable Notch Filter
For Simplicity Use R3 = R4 = R5 = 10k;
R5 = 1.234, fCLK = 79.3
fNOTCH
R2
1
R4
R5
R1
VIN
R2 1
2
FB
BOUT
AGND
OUT
8
R3
–
7
LTC1062
–5V
3
4
V–
V+
DIVIDER COSC
RATIO
VOUT
+
6
5
5V
fCLK
1062 TA08
Frequency Response of the Bandpass Filter
Frequency Response of the Notch Filter
20
–10
VS = ±5V
R1 = 1
R2
R′1 = 0.8
R′2
VIN = 100mVRMS
10
0
–10
–30
10
20
(dB)
(dB)
–20
0
–40
30
–50
40
–60
50
–70
60
–80
–90
0.5
1
1.5
2
2.5
(kHz)
3
3.5
4
4.5
70
100
300
500
700
900
1100
(Hz)
1062 TA09
1062 TA10
1062fd
9
LTC1062
U
TYPICAL APPLICATIO S
Simple Cascading Technique
5V
25.8k
412k
3
VIN
1µF
1
2
FB
BOUT
AGND
OUT
8
1
7
2
3
4
V–
BOUT
AGND
OUT
8
2
7
DIVIDER COSC
RATIO
6
–5V
5
3
4
V–
V+
DIVIDER COSC
RATIO
8
–
DC ACCURATE
OUTPUT
4
1
LTC1062
V+
6
LTC1052
FB
LTC1062
–5V
7
+
0.1µF
0.1µF
0.1µF
6
5
–5V
V + = 5V
10Hz, 10TH ORDER DC ACCURATE LOWPASS FILTER
60dB/OCTAVE ROLLOFF
0.5dB PASSBAND ERROR, 0dB DC GAIN
MAXIMUM ATTENUATION 110dB (fCLK = 10kHz)
100dB (fCLK = 1kHz)
95dB (fCLK = 1MHz)
1062 TA11
fCLK = 1kHz
100Hz, 50Hz, 25Hz 5th Order DC Accurate LP Filter
25.8k
VOUT
VIN
0.1µF
1
2
0.1µF
0.2µF
1
3
2
13
1/2 CD4016 4
FB
BOUT
AGND
OUT
8
7
5
BOUT
LTC1062
–5V
3
4
CONTROL
(HIGH, GROUND, LOW)
V–
V+
DIVIDER COSC
RATIO
100k
5V
100k
6
5
5V
10kHz
CLK IN
TO PIN 5 OF CD4016
BY CONNECTING PIN 4 OF THE LTC1062
HIGH/GROUND/LOW THE FILTER CUTOFF
FREQUENCY IS 100Hz/50Hz/25Hz
–5V
5V
100k
TO PIN 13 OF CD4016
100k
–5V
1062 TA12
1062fd
10
LTC1062
U
TYPICAL APPLICATIO S
7th Order 100Hz Lowpass Filter with Continuous Output Filtering, Output Buffering and Gain Adjustment
R4
R3
5V
2
2.6k
R1
3
VIN
1
C1
2
FB
BOUT
AGND
OUT
6
LTC1052
R2
1µF
7
–
C2
VOUT
8
+
4
0.1µF
1
0.1µF
8
–5V
7
LTC1062
–5V
5V
3
4
V–
V+
DIVIDER COSC
RATIO
6
5
5V
10kHz
CLK IN
1062 TA13
THE LTC1052 IS CONNECTED AS A 2ND ORDER SALLEN AND KEY LOWPASS FILTER WITH A CUTOFF
FREQUENCY EQUAL TO THE CUTOFF FREQUENCY OF THE LTC1062. THE ADDITIONAL FILTERING
ELIMINATES ANY 10kHz CLOCK FEEDTHROUGH PLUS DECREASES THE WIDEBAND NOISE OF THE FILTER
DC OUTPUT OFFSET (REFERRED TO A DC GAIN OF UNITY) = 5µV MAX
WIDEBAND NOISE (REFERRED TO A DC GAIN OF UNITY) = 60µVRMS
OUTPUT FILTER COMPONENT VALUES
DC GAIN R3
R4
R1
R2
C1
C2
1
∞
0
14.3k 53.6k 0.1µF 0.033µF
10
3.57k 32.4k 46k 274k 0.01µF 0.02µF
Single 5V Supply 5th Order LP Filter
R
10µF
SOLID
TANTALUM
5V
VIN
C
1
25k
+
2
C
FB
BOUT
AGND
OUT
8
7
DC ACCURATE
OUTPUT
BUFFERED
OUTPUT
LTC1062
25k
3
5V
4
V–
V+
DIVIDER COSC
RATIO
6
5
5V
CLK
12R
1062 TA14
FOR A 10Hz FILTER: R = 29.4k, C = 1µF, fCLK = 1kHz
1 = fC
THE FILTER IS MAXIMALLY FLAT FOR
2πRC 1.84
1062fd
11
LTC1062
U
TYPICAL APPLICATIO S
A Lowpass Filter with a 60Hz Notch
C7
0.1µF
R6
19.35k
R3
20k
R7
20k
R4
10k
R
9.09k
VIN
C
1µF
1
2
FB
8
BOUT
AGND
R2
20k
–
7
OUT
+
LTC1062
V
–
3
4
6
V+
V–
R5
10k
A1
1/2 LT1013
5
DIVIDER COSC
RATIO
–
A2
1/2 LT1013
+
V+
VOUT
1062 TA15
CLK IN
2.84kHz
1 = fCLK
2πRC 100 • 1.62
Frequency Response of the Above Lowpass Filter
with the Notch fNOTCH = fCLK/47.3
–10
0
VOUT/VIN (Hz)
10
20
30
40
50
60
70
1
10
100
1k
fIN (Hz)
1062 TA16
1062fd
12
LTC1062
U
PACKAGE DESCRIPTIO
J8 Package
8-Lead CERDIP (Narrow .300 Inch, Hermetic)
(Reference LTC DWG # 05-08-1110)
CORNER LEADS OPTION
(4 PLCS)
.023 – .045
(0.584 – 1.143)
HALF LEAD
OPTION
.045 – .068
(1.143 – 1.650)
FULL LEAD
OPTION
.005
(0.127)
MIN
.405
(10.287)
MAX
8
7
6
5
.025
(0.635)
RAD TYP
.220 – .310
(5.588 – 7.874)
1
2
.300 BSC
(7.62 BSC)
3
4
.200
(5.080)
MAX
.015 – .060
(0.381 – 1.524)
.008 – .018
(0.203 – 0.457)
0° – 15°
NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE
OR TIN PLATE LEADS
.045 – .065
(1.143 – 1.651)
.014 – .026
(0.360 – 0.660)
.100
(2.54)
BSC
.125
3.175
MIN
J8 0801
OBSOLETE PACKAGE
1062fd
13
LTC1062
U
PACKAGE DESCRIPTIO
N8 Package
8-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
.400*
(10.160)
MAX
8
7
6
5
1
2
3
4
.255 ± .015*
(6.477 ± 0.381)
.300 – .325
(7.620 – 8.255)
.008 – .015
(0.203 – 0.381)
+.035
.325 –.015
(
8.255
+0.889
–0.381
)
.045 – .065
(1.143 – 1.651)
.130 ± .005
(3.302 ± 0.127)
.065
(1.651)
TYP
.100
(2.54)
BSC
.120
(3.048) .020
MIN
(0.508)
MIN
.018 ± .003
(0.457 ± 0.076)
N8 1002
NOTE:
1. DIMENSIONS ARE
INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
1062fd
14
LTC1062
U
PACKAGE DESCRIPTIO
SW Package
16-Lead Plastic Small Outline (Wide .300 Inch)
(Reference LTC DWG # 05-08-1620)
.050 BSC .045 ±.005
.030 ±.005
TYP
.398 – .413
(10.109 – 10.490)
NOTE 4
16
N
15
14
13
12
11 10
9
N
.325 ±.005
.420
MIN
.394 – .419
(10.007 – 10.643)
NOTE 3
1
2
3
N/2
N/2
RECOMMENDED SOLDER PAD LAYOUT
1
.005
(0.127)
RAD MIN
.009 – .013
(0.229 – 0.330)
.291 – .299
(7.391 – 7.595)
NOTE 4
.010 – .029 × 45°
(0.254 – 0.737)
3
4
5
6
7
.093 – .104
(2.362 – 2.642)
8
.037 – .045
(0.940 – 1.143)
0° – 8° TYP
NOTE 3
.016 – .050
(0.406 – 1.270)
NOTE:
1. DIMENSIONS IN
2
.050
(1.270)
BSC
.004 – .012
(0.102 – 0.305)
.014 – .019
(0.356 – 0.482)
TYP
INCHES
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS.
THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS
4. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
S16 (WIDE) 0502
1062fd
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LTC1062
U
TYPICAL APPLICATIO
A Low Frequency, 5Hz Filter Using Back-to-Back Solid Tantalum Capacitors
5.23k
VIN
VOUT
+
10µF
10µF
+
1
2
FB
BOUT
AGND
OUT
8
BVOUT
7
LTC1062
–5V
3
4
V–
V+
DIVIDER COSC
RATIO
6
5V
5
0.08µF
1062 TA17
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1063
5th Order Butterworth Lowpass, DC Accurate
Clock Tunable, No External Components
LTC1065
5th Order Bessel Lowpass, DC Accurate
Clock Tunable, No External Components
LTC1066-1
8th Order Elliptic or Linear Phase, DC Accurate
Clock Tunable, fc ≤ 120kHz
LTC1563-2/
LTC1563-3
Active RC, 4th Order Lowpass
Very Low Noise, 256Hz ≤ fc ≤ 256kHz
LTC1564
10kHz to 150kHz Digitally Controlled Lowpass and PGA
Continuous Time, Very High Dynamic Range, PGA Included
LTC1569-6
Linear Phase, DC Accurate, 10th Order
No External Clock Required, fc ≤ 64kHz, S08
LTC1569-7
Linear Phase, DC Accurate, 10th Order
No External Clock Required, fc ≤ 300kHz, S08
1062fd
16
Linear Technology Corporation
LW/TP 1102 1K REV D • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
 LINEAR TECHNOLOGY CORPORATION 1994