LTC1067 Datasheet, PDF (1/20 Pages) Linear Technology – Rail-to-Rail, Very Low Noise Universal Dual Filter Building Block

LTC1067/LTC1067-50
Rail-to-Rail, Very Low Noise
Universal Dual Filter Building Block
FEATURES
s _{Rail-to-Rail Input and Output Operation}
s _{Operates from a Single 3V to ±5V Supply}
s _{Dual 2nd Order Filter in a 16-Lead SSOP Package}
s _{> 80dB Dynamic Range on Single 3.3V Supply}
s _{Clock-to-Center Frequency Ratio of 100:1 for the}
LTC1067 and 50:1 for the LTC1067-50
s _{Internal Sampling-to-Center Frequency Ratio of}
200:1 for the LTC1067 and 100:1 for the LTC1067-50
s _{Center Frequency Error < ±0.2% Typ}
s _{Low Noise: < 40µVRMS, Q ≤ 5}
s _{Customizable with Internal Resistors}
U
APPLICATIONS
s _{Notch Filters}
s _{Narrowband Bandpass Filters}
s _{Tone Detection}
s _{Noise Reduction Systems}
, LTC and LT are registered trademarks of Linear Technology Corporation.
DESCRIPTION
The LTC^®1067/LTC1067-50 consist of two identical rail-
to-rail, high accuracy and very wide dynamic range 2nd
order switched-capacitor building blocks. Each building
block, together with three to five resistors, provides 2nd
order filter functions such as bandpass, highpass, lowpass,
notch and allpass. High precision 4th order filters are
easily designed.
The center frequency of each 2nd order section is tuned by
the external clock frequency. The internal clock-to-center
frequency ratio (100:1 for the LTC1067 and 50:1 for the
LTC1067-50) can be modified by the external resistors.
These devices have a double sampled architecture which
places aliasing and imaging components at twice the clock
frequency. The LTC1067-50 is a low power device con-
suming about one half the current of the LTC1067. The
LTC1067-50’s typical supply current is about 1mA from a
3.3V supply.
The LTC1067 and LTC1067-50 are available in 16-pin
narrow SSOP and SO packages.
Mask programmable versions of the LTC1067 and
LTC1067-50, with thin film resistors on-chip and custom
clock-to-cutoff frequency ratios, can be designed in an
SO-8 package to realize application specific monolithic
filters. Please contact LTC Marketing for more details.
TYPICAL APPLICATION
Single 3.3V Supply Rail-to-Rail,
4th Order, 10kHz Bandpass Filter
1 _V+
CLK ¹⁶ f_CLK = 500kHz
2
NC
15
AGND
3.3V
3 _V+
V^{– 14}
1µF
0.1µF
4
13
SA
SB
5
LTC1067-50
LPA
LPB
12
R31, 200k ₆
BPA
11
BPB
R21, 10k ₇
10
R11
HPA/NA HPB/NB
200k
IN
8
INV A
9
INV B
OUT
R32, 200k
R22, 10k
RB1, 200k
TOTAL OUTPUT NOISE: 90µV_RMS
S/N RATIO: 80dB
1067 TA01
Frequency Response
0
–10
–20
–30
–40
8
9
10
11
FREQUENCY (kHz)
12
1067 • TA02
1