Quick Test Procedure - Linear Technology DC961B Demo Manual

DEMO MANUAL DC961B

Quick test proceDure

A. Single-Ended Input to Differential Output
1. Connect to a DC961 a dual power supply, a function
generator and an oscilloscope as shown in Figure 3
(the 50Ω termination on J2 input is used to balance
the 50Ω generator impedance on J1 input).
2. Set the function generator for a 1V
ewave and turn on the power supply.
3. The channel 2 input of the oscilloscope is in phase with
the DC961 input and the channel 1 input is 180 degrees
out of phase with the DC961 input. The single-ended
output shown on channel 1 or 2 is a 0.5V
(a 1V differential output).
P-P
FUNCTION
GENERATOR
BNC_T
50
OUTPUT
V
IMPEDANCE
BNC
TO
V
SMA
IN
SET FUNCTION
GENERATOR
TO A 1V ,
P-P
100kHz
SINEWAVE
V
50
TERMINATION
BNC
TO
SMA
2
, 100kHz sin-
P-P
sinewave
P-P
DUAL POWER SUPPLY
5V
+
V
+
IN
C8, 1µF
R2 Z1
J1
0 0 499
SHDN
PWR_ON
JP1
0.1µF
–
IN
C12, 1µF
R6 Z2 R8
J2
0 0 499
EXT
V JP3
100
OCM
EXT
INT
Figure 3. Single-Ended Input to Differential Output Quick Test Setup
Note 1: The LT1994 can directly drive at least a 25pF
capacitive load at each output. However the LT1994 can
drive directly a low frequency sinewave (100kHz or less)
into a capacitive load of up to 100pF. In this Quick Test
Procedure, the output signal is a sinewave and each
LT1994 output drives the capacitance of a 24 inch or
less cable plus the input capacitance of the oscilloscope
input, a capacitive load of 70pF (30pF per foot for the coax
cable and 10pF for the oscilloscope input). For testing the
transient response of the LT1994 to a squarewave or a
pulse, use a 10x low capacitance oscilloscope probe to
monitor the DC961 output at J3 or J4.
–5V
DC961
–
V
TO JP2
R5
R9
499
+
V
0.1µF
3
8
R12, 50
–
5
+
7
V LT1994
2
OCM
R15, 50
–
1
+
4
6
0.1µF
R4
499
+
V
10k
JP2
SINGLE
DUAL
10k
–
V
COAX CABLE
OSCILLOSCOPE
CH2
CH1
CH1 CH2 EXT
SMA
TO
BNC
J3
–
V
OUT
SET THE OSCILLOSCOPE
J4
TO EXTERNAL TRIGGER
+
V
OUT SMA
TO
24 INCHES OR
BNC
LESS COAX CABLE
DC961 JUMPERS SETTINGS:
JP1 LT1994, SHDN PIN TO GND OR OPEN
– –
JP2 LT1994, V PIN TO V OR GND
+
JP3 LT1994, V PIN TO V /2 OR
OCM
AN EXTERNAL CONNECTION
DC961b
dc961bf