SP3223EEY-L-TR Datasheet, PDF (12/21 Pages) Exar Corporation – Intelligent +3.0V to +5.5V RS-232 Transceivers

V_CC = +5V
+
C_{1 –}
–5V
+5V
+
C_{2 –}
–5V
Figure 16. Charge Pump - Phase 1
V_CC = +5V
+
C_{1 –}
+
C_{2 –}
–10V
C₄
+ – V_DD Storage Capacitor
– + _{VSS Storage Capacitor}
C₃
C₄
+ – _{VDD Storage Capacitor}
– + _{VSS Storage Capacitor}
C₃
Figure 17. Charge Pump - Phase 2
[
T
a) C2+
1
T
2
2
]
+6V
0V
0V
b) C2-
T
-6V
Ch1 2.00V Ch2 2.00V M 1.00ms Ch1 1.96V
Figure 18. Charge Pump Waveforms
V_CC = +5V
+
C_{1 –}
–5V
+5V
+
C_{2 –}
–5V
C₄
+ – _{VDD Storage Capacitor}
– + _{VSS Storage Capacitor}
C₃
Figure 19. Charge Pump - Phase 3
V_CC = +5V
+
C_{1 –}
+10V
+
C_{2 –}
C₄
+ – V_DD Storage Capacitor
–+
C₃
V_SS Storage Capacitor
Figure 20. Charge Pump - Phase 4
Minimum recommended charge pump capacitor value
Input Voltage V_CC
Charge pump capacitor value
3.0V to 3.6V
C1 - C4 = 0.1µF
4.5V to 5.5V
C1 = 0.047µF, C2-C4 = 0.33µF
3.0V to 5.5V
C1 - C4 = 0.22µF
Table 4. Minimum Charge Pump Capacitor values
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • [phone] • www.exar.com
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SP3223E/EB/EU_101_062712