MAX3222EC/D MAXIM [Maxim Integrated Products], MAX3222EC/D Datasheet - Page 12

• Manufacturer Part Number: MAX3222EC/D
• Manufacturer: MAXIM [Maxim Integrated Products]

The capacitor type used for C1–C4 is not critical for
proper operation; polarized or nonpolarized capacitors
can be used. The charge pump requires 0.1µF capaci-
tors for 3.3V operation. For other supply voltages, see
Table 2 for required capacitor values. Do not use val-
ues smaller than those listed in Table 2. Increasing the
capacitor values (e.g., by a factor of 2) reduces ripple
on the transmitter outputs and slightly reduces power
consumption. C2, C3, and C4 can be increased without
changing C1’s value. However, do not increase C1
without also increasing the values of C2, C3, C4,
and C
the other capacitors).
When using the minimum required capacitor values,
make sure the capacitor value does not degrade
±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
Up to 1Mbps, True RS-232 Transceivers
Figure 6b. Mouse Driver Test Circuit
12
______________________________________________________________________________________
BYPASS
to maintain the proper ratios (C1 to
Applications Information
V
CC
V
= +3.0V TO +5.5V
C1
C2
CC
Capacitor Selection
28
24
14
13
12
21
20
19
18
17
16
15
23
1
2
C1+
C2+
C2-
T2IN
T3IN
R2OUTB
R1OUT
R2OUT
R3OUT
R4OUT
R5OUT
C1-
T1IN
R1OUTB
EN
C
BYPASS
MAX3241E
V
GND
CC
26
25
5kΩ
5kΩ
5kΩ
5kΩ
5kΩ
T1OUT 9
T2OUT 10
T3OUT 11
SHDN 22
R1IN 4
R2IN 5
R3IN
R4IN 7
R5IN 8
V+
V-
27
3
6
excessively with temperature. If in doubt, use capaci-
tors with a larger nominal value. The capacitor’s equiv-
alent series resistance (ESR), which usually rises at low
temperatures, influences the amount of ripple on V+
and V-.
In most circumstances, a 0.1µF V
is adequate. In applications sensitive to power-supply
noise, use a capacitor of the same value as charge-
pump capacitor C1. Connect bypass capacitors as
close to the IC as possible.
Transmitter outputs meet EIA/TIA-562 levels of ±3.7V
with supply voltages as low as 2.7V.
V
CC
C3
C4
COMPUTER SERIAL PORT
GND
+V
-V
+V
Tx
Power-Supply Decoupling
Operation Down to 2.7V
MOUSE
CC
bypass capacitor