sp3508 Exar Corporation, sp3508 Datasheet - Page 26

• Manufacturer Part Number: sp3508
• Description: Rugged 3.3v, 20mbps, 8 Channel Multiprotocol Tranciever With Programmable Dce/dte And Terminination Resistors
• Manufacturer: Exar Corporation

Figure 48. Charge Pump - Phase 4.
2-phased inverter pump
Phase 1
Please refer to figure below: In the first phase of the clock cycle, switches S2 and S4 are opened and S1 and
S3 closed. This connects the flying capacitor, C3, from Vin to ground. C3 charge up to the input voltage
applied at Vcc.
Phase 2
In the second phase of the clock cycle, switches S2 and S4 are closed and S1 and S3 are opened. This
connects the flying capacitor, C3, in parallel with the output capacitor, C
now transferred to C
side is connected to ground. With the voltage across C
flows from C3 to C
Figure 49. Circuit for an Ideal Voltage Inverter.
Date: 10/29/04
VSS2
V
VSS2
CC
. Simultaneously, the negative side of C
until the voltage at the V
C
1
+
–
V
SP3508 Enhanced WAN Multi–Mode Serial Transceiver
CC
= +3V
S
S
3
1
C
V
C
2
+6V
SS2
3
+
–
SS2
26
= -V
equals -V
+
VSS2
CC
smaller than the voltage across C3, the charge
S
C
C
S
+
–
VDD
4
VSS1
CC
2
VSS2
+
–
.
V
V
DD
SS1
is connected to V
Storage Capacitor
+
Storage Capacitor
VSS2
C
VSS2
. The Charge stored in C3 is
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V
SS2
SS2
and the positive
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