MAX218EWP Maxim Integrated, MAX218EWP Datasheet - Page 6

• Manufacturer Part Number: MAX218EWP
• Description: RS-232 Interface IC
• Manufacturer: Maxim Integrated
• Series: MAX218r

Specifications of MAX218EWP

• Data Rate: 120 Kbps
• Operating Supply Voltage: 3 V
• Supply Current: 3 mA
• Operating Temperature Range: 0 C to + 70 C
• Function: Transceiver
• Number Of Drivers: 2
• Number Of I/os: 8
• Number Of Receivers: 2
• Propagation Delay Time Ns: 2.7 us, 0.7 us
• Shutdown: Yes

The two drivers are identical, and deliver EIA/TIA-232E
and EIA/TIA-562 output voltage levels when V
between 1.8V and 4.25V. The transmitters drive up to
3kΩ in parallel with 1000pF at up to 120kbps. Connect
unused driver inputs to either GND or V
drivers by taking S
forced into a high-impedance state when S
The two receivers are identical, and accept both
EIA/TIA-232E and EIA/TIA-562 input signals. The
CMOS receiver outputs swing rail-to-rail. When EN is
high, the receivers are active regardless of the state of
S
into a high-impedance state. This allows two RS-232
ports (or two ports of different types) to be wired-ORed
at the UART.
S
tion, as shown in Table 2.
Table 2. Operating Modes
1.8V to 4.25V-Powered,
True RS-232 Dual Transceiver
Table 1. Suggested Component Suppliers
—
—
6
–
Diodes—Through-Hole
S
—
Inductors—Surface Mount
Diodes—Surface Mount
H
H
—
—
H
—
H
H
Murata-Erie
Sumida
TDK
Central Semiconductor
Motorola
Philips
Motorola
D
D
L
L
—
—
D
_______________________________________________________________________________________
—
N
N
N
–
–
–
. When EN is low, the receiver outputs are put
MANUFACTURER
and EN determine the MAX218’s mode of opera-
EN
H
H
L
L
RECEIVER
OUTPUT
Enabled
Enabled
High-Z
High-Z
—
H
—
D
—
N
–
OUTPUT
DRIVER
Enabled
Enabled
High-Z
High-Z
low. The transmitter outputs are
CONVERTER
RS-232 Receivers
Operating Modes
LQH4N150K-TA
CD43150
NLC453232T-150K
CMPSH-3, Schottky
MMBD6050LT1, Silicon
PMBD6050, Silicon
1N6050, Silicon
1N5817, Schottky
DC-DC
OFF
OFF
ON
ON
PART NUMBER
RS-232 Drivers
CC
—
H
. Disable the
—
D
—
N
CURRENT
–
Minimum
Minimum
SUPPLY
Normal
Normal
is low.
DD
is
When S
the transmitters are put into a high-impedance state.
Receiver operation is not affected by taking S
Power consumption is dramatically reduced in shutdown
mode. Supply current is minimized when the receiver
inputs are static in any of three states: floating (ground),
GND, or V
The MAX218 is intended for use with three different
power-supply sources: it can be powered directly from
a battery, from a 3.0V or 3.3V power supply, or simulta-
neously from both. Figure 1 shows the single-supply
configuration. Figure 2 shows the circuit for operation
from both a 3V supply and a raw battery supply—an
ideal configuration where a regulated 3V supply is
being derived from two cells. In this application, the
MAX218’s logic levels remain appropriate for interface
with 3V logic, yet most of the power for the MAX218 is
drawn directly from the battery, without suffering the
efficiency losses of the DC-DC converter. This pro-
longs battery life.
Bypass the input supplies with 0.1µF at V
least 1µF at the inductor (C5). Increase C5 to 4.7µF if
the power supply has no other bypass capacitor con-
nected to it.
__________Applications Information
USA [phone]
Japan [phone]
USA [phone]
Japan [phone]
USA [phone]
Japan [phone]
USA [phone]
USA [phone]
USA [phone]
USA [phone]
Operation from Regulated/Unregulated
—
H
—
PHONE
D
—
CC
N
–
.
is low, the power supplies are disabled and
Dual System Power Supplies
USA [phone]
Japan [phone]
USA [phone]
Japan [phone]
USA [phone]
Japan [phone]
USA [phone]
USA [phone]
USA [phone]
USA [phone]
FAX
CC
Shutdown
(C4) and at
—
H
—
D
—
N
–
low.