LTC1067-50IS#TRPBF Linear Technology, LTC1067-50IS#TRPBF Datasheet - Page 15

• Manufacturer Part Number: LTC1067-50IS#TRPBF
• Description: IC FILTR BLDNGBLK R-R DUAL16SOIC
• Manufacturer: Linear Technology

Specifications of LTC1067-50IS#TRPBF

• Filter Type: Universal Switched Capacitor
• Frequency - Cutoff Or Center: 40kHz
• Number Of Filters: 2
• Max-order: 4th
• Voltage - Supply: 2.7 V ~ 11 V, ±2.7 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIONS
Figure 14 illustrates how a resistor adjusts the AGND
voltage for use with a 3V/3.3V powered ADC with a full-
scale input of 2.048V. As in the previous circuit, the
resistor value was chosen carefully to assure that a 2.048V
input signal to the filter yields a full-scale reading from the
ADC and a 0V input signal gives the lowest possible value.
For this application, the power supply must be above 2.7V
for an LTC1067-50 filter and above 3V for an LTC1067
filter.
Semi-Custom Filter Program
Linear Technology has in place a program to deliver fully
integrated filters, custom designed for any specified appli-
cation. These semi-custom filters are based on an existing
universal filter product with integrated, on-chip resistors.
The final filter is then tested to the exact parameters
defined for the application. The final result is a fully
integrated, accurately tested solution in a smaller pack-
age. For the LTC1067 or LTC1067-50 parts, a semi-
custom filter comes in the SO-8 package and requires only
a clock and a decoupling capacitor. For more details on the
semi-custom filter program, contact Linear Technology’s
marketing department.
Demonstration Board
There is a demonstration board available for the LTC1067/
LTC1067-50. Demonstration board 150A has the LTC1067
part installed and the board 150B has the LTC1067-50
installed. The schematic for the board is shown in Figure
15 and the assembly drawing is shown in Figure 16. To
(LTC1067-50)
2.7V TO 3.6V
3V TO 3.6V
(LTC1067)
Figure 14. Power and AGND Connections for
3V/3.3V ADC with 2.048V Full Scale
0.1 F
1
2
3
4
5
6
7
8
U
V
NC
V
SA
LPA
BPA
HPA/NA
INV A
+
+
INFORMATION
LTC1067-50
U
LTC1067
HPB/NB
AGND
INV B
CLK
LPB
BPB
SB
W
V
–
16
15
14
13
12
11
10
9
1067 F14
1 F
U
33.2k
1%
obtain a demonstration board, call your local representa-
tive or Linear Technology’s marketing department.
The demonstration board has all integrated circuits, con-
nectors and decoupling capacitors installed. The board is
ready to be configured with the appropriate resistors and
jumper connections.
There are two sets of power supply connections. One is for
the LTC1067/LTC1067-50 and the other is for the buffer-
ing op amp on the board. Having separate connections
gives the board the most flexibility. The two sets of
supplies can be connected together if a common supply is
desired.
When configuring the board for split supply operation, a
jumper wire must be installed in the JPAGND position.
This connects the AGND pin of the device to the ground
plane of the board. The JPVNEG jumper must be left open.
The power supply is then connected to V
turrets (all of the GND turrets on the board are the same).
For single supply operation, insert a wire in the JPVNEG
jumper and leave the JPAGND jumper open. This connects
the V
jumper must be left open so that the on-chip resistor
network can set the AGND potential at the midpoint of the
supply. Connect the power supply to V
turret. The V
adjacent GND turret. If the buffering op amp is run on the
same single voltage supply, the VOA
turrets must be connected together and the VOA
must be shorted to the adjacent GND turret.
The J1 BNC connector is the clock input. There is a 200
series resistor connected between the connector and the
CLK pin of the part. This resistor, coupled with the CLK
pin’s input capacitance, slows down the rise and fall times
of the clock signal and decreases high frequency coupling.
The clock input is not terminated to 50
external terminator should be used.
Jumpers JP51 and JP61 are connected in parallel with
R51 and R61 respectively. Jumper JP51 connects the LPA
pin of the part with the SA pin. This can be used for
operating modes 1 or 2. Alternatively, a 0 resistor in the
R51 position fulfills the same requirement. The JP61
jumper connects the SA pin of the part to the AGND pin.
–
pin to the board’s ground plane. The JPAGND
–
turret can be left open or shorted to the
LTC1067/LTC1067-50
+
turret and the V
+
+
, V
and any GND
or 75 . An
–
and GND
15
–
turret
+