Datasheet

 
SBVS028B − DECEMBER 2000 − REVISED DECEMBER 2007
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7
APPLICATION NOTES
DCR02 SINGLE VOLTAGE OUTPUT
The DCR02 can be used to provide a single voltage output
by connecting the circuit as shown in Figure 3. The
ERROR
output signal is pulled up to the value of V
OUT
for
the particular DCR02 being used. The value of R
ERR
depends on the loading on the ERROR line; however, the
total load on the ERROR
line must not exceed the value
given in the specification.
The output can be permanently enabled by connecting the
ENABLE pin to the V
REC
pin. The DCR02 can be enabled
remotely by connecting the ENABLE pin to V
REC
via a
pull-up resistor (R
EN
); the value of this resistor is not critical
for the DCR02 since only a small current flows. Switch
SW1 can be used to pull the ENABLE pin low, thus
disabling the output. The switching devices can be a
bipolar transistor, FET, or a mechanical device; the main
load that it senses is R
EN
.
GENERATING TWO POSITIVE OUTPUT
VOLTAGES
Two DCR02s can be used to create two +5−V output
voltages, as shown in Figure 4. The two DCR02s are
connected in self-synchronization, thus locking the
oscillators of both devices to a single frequency.
The ERROR
and ENABLE facilities can be used in a
similar configuration for a single DCR02. The filter
capacitors connected to the V
REC
pins (C
FILTER
) should be
kept separate from each other and connected in close
proximity to the respective DCR02. If similar output
voltages are being used, it is not recommended that a
single filter capacitor (with an increased capacitance) be
used with both V
REC
pins connected together, since this
could result in the overloading of one of the devices.
DCR 02
V
OUT
V
IN
C
OUT
0.1
µ
F
R
ERR
10k
Ω
C
FILTER
1
µ
F
C
FILTER
1
µ
F
V
O1
0V
ENABLE
V
REC
ERROR
V
S
U1
0V
SYNC
ERROR
DCR 02
V
OUT
V
IN
C
OUT
0.1
µ
F
R
ERR
10k
Ω
V
O2
0V
ENABLE
V
REC
ERROR
V
S
U2
0V
SYNC
0V
OUT
ERROR
C
IN
(1)
C
IN
(1)
NOTE: (1) Required 2.2
µ
F low ESR ceramic capacitor.
Figure 4. Generating Two Positive Voltages from Self-Synchronized DCR02s