SP332CT-L/TR Exar Corporation, SP332CT-L/TR Datasheet - Page 7

• Manufacturer Part Number: SP332CT-L/TR
• Description: Programmable RS232/RS485 Transceiver
• Manufacturer: Exar Corporation
• Type: Transceiverr

Specifications of SP332CT-L/TR

• Number Of Drivers/receivers: 4/4
• Protocol: RS232, RS485
• Voltage - Supply: 5V
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (0.300", 7.50mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Phase 3
of the clock is identical to the first phase
— the charge transferred in C
–5V in the negative terminal of C
is applied to the negative side of capacitor
C
across C
Phase 4
clock connects the negative terminal of C
to ground and transfers the generated l0V
across C
Again, simultaneously with this, the positive
side of capacitor C
the negative side is connected to ground,
and the cycle begins again.
Figure 7. Charge Pump Waveforms
Figure 8. Charge Pump Phase 1.
Figure 10. Charge Pump Phase 2.
— V
— V
2
. Since C
DD
DD
C
C
1
1
transfer — The fourth phase of the
charge storage — The third phase
+
–
+
–
2
2
V
V
CC
CC
is l0V.
to C
2
= +5V
= +5V
+
is at +5V, the voltage potential
4
, the V
C
C
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 50-668-707 • www.exar.com
2
a) C2+
2
b) C2-
–10V
+10V
+
–
+
–

is switched to +5V and
GND
DD
GND
+10V
-10V
storage capacitor.
+
–
+
–
C
C
C
C
4
4
+
–
3
+
3
–
V
V
V
V
DD
SS
DD
SS

Storage Capacitor
Storage Capacitor
Storage Capacitor
Storage Capacitor
produces

, which
2
7
Since both V+ and V
erated from V
and V
pump approaches that generate V
V+ will show a decrease in the magnitude
of V
inefficiencies in the design.
The clock rate for the charge pump typically
operates at 15kHz. The external capaci-
tors must be 0.1µF with a 16V breakdown
rating.
Figure 11. Charge Pump Phase 4.
Figure 9. Charge Pump Phase 3.
–
–
compared to V+ due to the inherent
C
C
1
1
–5V
will be symmetrical. Older charge
–5V
+
–
+
–
V
V
CC
CC
= +5V
= +5V
CC
in a no–load condition, V+
C
C
2
2
+5V
–5V
+5V
–5V
+
+
–
–
–
are separately gen-
+
–
+
–
C
C
C
C
4
4
3
+
3
–
+
–
V
V
SP332_00_0260
V
V
DD
SS
DD
SS
Storage Capacitor
Storage Capacitor
Storage Capacitor
Storage Capacitor
–
from