1
LTC1564
1564fa
10kHz to 150kHz
Digitally Controlled
Antialiasing Filter and 4-Bit P.G.A.
■
4-Bit Digitally Controlled 8th-Order Lowpass Filter
–f
CUTOFF
Adjustable from 10kHz to 150kHz in 10kHz
Steps
– 100dB Attenuation at 2.5 × f
CUTOFF
■
4-Bit Digitally Controlled Programmable Gain
Amplifier
– G = 1 to 16 in 1V/V Steps
■
Miniature 16-Pin SSOP Package
■
No External Components
■
122dB Total System Dynamic Range
■
Rail-to-Rail Input and Output Range
■
2.7V to 10V Operation
■
Low Noise Mute Mode
■
Low Power Shutdown Mode
■
Available in 16-Lead Plastic SSOP Package
■
Antialias or Reconstruction Filtering
■
DSP Systems
■
Communications Systems
■
Scientific Instruments
■
High Resolutions (16 Bits to 20 Bits)
■
Processing Signals Buried in Noise
■
Audio Signal Processing
■
Programmable Data Rates
■
Automatic Gain Control (AGC)
■
Single Part Replacing Multiple Filters
Low Noise Programmable Filter with Variable Gain
The LTC
®
1564 is a new type of continuous time filter for
antialiasing, reconstruction and other band-limiting appli-
cations. No other analog components or filter expertise are
needed to use it. There is one analog input pin and one
analog output pin. The cutoff frequency (f
C
) and gain are
programmable while the shape of the lowpass response is
fixed. A latching digital interface stores f
C
and gain settings
or it can be bypassed for control directly from the pins. The
LTC1564 operates from 2.7V to 10V total (single or split
supplies) and comes in a 16-pin surface mount SSOP.
The LTC1564 is a rail-to-rail high resolution 8th-order
lowpass filter with two stopband notches, giving approxi-
mately 100dB attenuation at 2.5 times the passband cutoff
frequency f
C
(a de-facto standard for DSP front ends).
Signals with low or variable levels can be normalized with
the built-in variable gain that reduces input-referred noise
with increasing gain for a typical dynamic range (maxi-
mum signal level to minimum noise) of 122dB (20 equiva-
lent bits) with 20kHz f
C
and 118dB at 100kHz f
C
on a ±5V
supply.
Other frequency-response shapes can be provided upon
request. Please contact LTC Marketing.
IN AGND V
+
RST G3
LTC1564
G2 G1 G0
OUT V
–
1234567
1564 TA01
8
16 15 14 13 12 11
GAIN CODE
FREQUENCY CODE
V
+
AND V
–
SUPPLIES CAN BE FROM
1.35V TO 5.25V EACH
TIE F AND G PINS TO V
+
OR V
–
TO
SET FREQUENCY AND GAIN
DYNAMIC RANGE 118dB TO 122dB
AT ± 5V DEPENDING ON FREQUENCY CODE
0.1µF
V
+
10 9
EN
CS/
HOLD F3 F2 F1 F0
0.1µF
ANALOG
OUT
ANALOG
IN
V
–
LTC1564 Programmable Range
FREQUENCY (kHz)
5
GAIN (dB)
10 100 500
1564 TA02
10
30
20
0
–10
–20
–30
–40
–50
–60
–70
–80
–120
–110
–100
–90
f
C
= 10kHz
GAIN = 1V/V
f
C
= 150kHz
GAIN = 16V/V
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
