MAX3218EAP+T Maxim Integrated Products, MAX3218EAP+T Datasheet - Page 6

• Manufacturer Part Number: MAX3218EAP+T
• Description: IC TXRS RS-232 W/SHTDWN 20SSOP
• Manufacturer: Maxim Integrated Products
• Type: Line Transceiverr

Specifications of MAX3218EAP+T

• Number Of Drivers/receivers: 2/2
• Protocol: RS232
• Voltage - Supply: 1.8 V ~ 4.25 V
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Key diode specifications are fast recovery time (<10ns),
average current rating (>100mA), and peak current rat-
ing (>350mA). Inexpensive fast silicon diodes, such as
the 1N6050, are generally recommended. More expen-
sive Schottky diodes improve efficiency and give slightly
better performance at very low V
lists suppliers of both surface-mount and through-hole
diodes. 1N914s are usually satisfactory, but specifica -
tions and performance vary widely with different manu-
facturers.
Use capacitors with values at least as indicated in
Figure 1. Capacitor C2 determines the ripple on V+, but
not the absolute voltage. Capacitors C1 and C3 deter -
mine both the ripple and the absolute voltage of V-.
Bypass V
to pins 5 and 6. If the V
where (e.g., at the power supply), increase C4 to 4.7µF.
You may use ceramic or polarized capacitors in all
locations. If you use polarized capacitors, tantalum
types are preferred because of the high operating fre-
quency of the power supplies (about 250kHz). If alu-
minum electrolytics are used, higher capacitance
values may be required.
1µA Supply Current, 1.8V to 4.25V-Powered
RS-232 Transceiver with AutoShutdown™
Table 1. Suggested Component Suppliers
6
Inductors
Diodes—Surface-Mount
Diodes—Through-Hole
Murata-Erie
Sumida
TDK
Allegro
Central Semiconductor
Motorola
Philips
Motorola
_______________________________________________________________________________________
MANUFACTURER
CC
to GND with at least 1 µF (C4) placed close
CC
line is not bypassed else -
LQH4N150K-TA
CD43150
NLC453232T-150K
TMPD6050LT
CMPSH-3 (Schottky)
MMBD6050LT1 (silicon)
PMBD6050 (silicon)
1N6050 (silicon),
1N5817 (Schottky)
CC
Capacitor Selection
PART NUMBER
voltages. Table 1
Diode Selection
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Figure 1. Typical Operating Circuit
1.8V to
4.25V
PHONE
1 F
C4
10
3
4
2
7
8
9
T1IN
FORCEON
FORCEOFF
INVALID
T2IN
R1OUT
R2OUT
6
V
CC
15 H
MAX3218
T1
T2
GND
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1
R2
R1
LX
5, 17, 20
1N6050
5k
5k
19
T1OUT
T2OUT
V+
R1IN
R2IN
C1+
C1-
V-
FAX
16
15
18
14
13
12
11
C1
0.47 F
C2
1 F
C3
1 F