Datasheet

7
LTC1067/LTC1067-50
PIN FUNCTIONS
UUU
V
+
, V
–
(Pins 1, 3,14): The V
+
(Pins 1, 3) and the V
–
(Pin
14) should each be bypassed with a 0.1µF capacitor to an
adequate analog ground. The filter’s power supplies should
be isolated from other digital or high voltage analog
supplies. A low noise linear supply is recommended.
Using a switching power supply will lower the signal-to-
TYPICAL PERFORMANCE CHARACTERISTICS
U
W
LTC1067/LTC1067-50 Mode 1B
Noise Increase vs R5/R6 Ratio
LTC1067/LTC1067-50 Mode 3
Noise Increase vs R2/R4 Ratio
R2/R4 RATIO
0.2
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.5 0.7
1067 G26
0.3 0.4
0.6 0.8 0.9 1.0
RELATIVE NOISE INCREASE
(REFERENCE NOISE WHEN R2/R4 = 1)
noise ratio of the filter. The supply’s power-up slew rate
should be less than 1V/µs. When V
+
is applied before V
–
, and
V
–
is allowed to go above ground, a diode should clamp V
–
to prevent latch-up. Figures 1 and 2 show typical connec-
tions for dual and single supply operation.
0.1µF
1067 F01
200Ω
LTC1067
LTC1067-50
CLOCK
SOURCE
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
STAR
SYSTEM
GROUND
DIGITAL
GROUND
PLANE
V
+
NC
V
+
SA
LPA
BPA
HPA/NA
INV A
CLK
AGND
V
–
SB
LPB
BPB
HPB/NB
INV B
V
+
V
–
0.1µF
Figure 1. Dual Supply Ground Plane Connections
Figure 2. Single Supply Ground Plane Connections
0.1µF
106 7 F02
200Ω
LTC1067
LTC1067-50
CLOCK
SOURCE
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
STAR
SYSTEM
GROUND
DIGITAL
GROUND
PLANE
V
+
NC
V
+
SA
LPA
BPA
HPA/NA
INV A
CLK
AGND
V
–
SB
LPB
BPB
HPB/NB
INV B
V
+
1µF
FOR MODE 3, THE SA AND SB SUMMING NODE PINS
ARE TIED TO THE AGND PIN
R5/R6 RATIO
0
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
1.5 2.5
1067 G25
0.5 1.0
2.0 3.0 3.5
RELATIVE NOISE INCREASE
(REFERENCE NOISE WHEN R5/R6 = 0.02)