Datasheet

Low Power, 3.3 V, RS-232
Line Drivers/Receivers
ADM3202/ADM3222/ADM1385
Rev. E
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FEATURES
460 kbps data rate
Specified at 3.3 V
Meets EIA-232E specifications
0.1 μF charge pump capacitors
Low power shutdown (ADM3222 and ADM1385)
PDIP, SOIC_N, SOIC_W, SSOP, and TSSOP options
Upgrade for MAX3222/MAX3232 and LTC1385
ESD protection to IEC 1000-4-2 (801.2)
on RS-232 pins (ADM3202 only)
±8 kV: contact discharge
±15 kV: air gap discharge
APPLICATIONS
General-purpose RS-232 data link
Portable instruments
Printers, palmtop computers, PDAs
GENERAL DESCRIPTION
The ADM3202/ADM3222/ADM1385 transceivers are high
speed, 2-channel RS-232/V.28 interface devices that operate
from a single 3.3 V power supply. Low power consumption and
a shutdown facility (ADM3222/ADM1385) make them ideal for
battery-powered portable instruments.
The ADM3202/ADM3222/ADM1385 parts conform to the
EIA-232E and CCITT V.28 specifications and operate at data
rates up to 460 kbps.
Four external 0.1 μF charge pump capacitors are used for the
voltage doubler/inverter, permitting operation from a single
3.3 V supply.
The ADM3222 contains additional enable and shutdown
circuitry. The
EN
input can be used to three-state the receiver
outputs. The
SD
input is used to power down the charge pump
and transmitter outputs, reducing the quiescent current to less
than 0.5 μA. The receivers remain enabled during shutdown
unless disabled using
EN
.
The ADM1385 contains a driver disable mode and a complete
shutdown mode.
The ADM3202 is available in a 16-lead PDIP, SOIC_W, and
SOIC_N, as well as a space-saving 16-lead TSSOP. The ADM3222
is available in 18-lead PDIP and SOIC_W and in 20-lead SSOP
and TSSOP. The ADM1385 is available in a 20-lead SSOP,
which is pin-compatible with the LTC1385 CG.
FUNCTIONAL BLOCK DIAGRAMS
C1+
C2+
C1–
C2–
V
CC
V–
V+
T1
IN
T1
OUT
T2
IN
T2
OUT
R1
OUT
R1
IN
R2
OUT
R2
IN
CMOS
INPUTS
EIA/TIA-232
OUTPUTS
CMOS
OUTPUTS
EIA/TIA-232
INPUTS*
T1
T2
R1
R2
+
+
+
0.1µF
10V
0.1µF
10V
GND
ADM3202
C3
0.1µF
6.3V
+3.3
V
INPUT
+3.3V TO +6.6V
VOLTAGE
DOUBLER
+6.6V TO –6.6V
VOLTAGE
INVERTER
C5
0.1µF
+
C4
0.1µF
10V
+
*INTERNAL 5kΩ PULL-DOWN RESISTOR
ON EACH RS-232 INPUT
00071-001
Figure 1.
C1+
C2+
C1–
C2–
V
CC
V–
V+
T1
IN
T1
OUT
T2
IN
T2
OUT
R1
OUT
R1
IN
R2
OUT
EN
R2
IN
SD
CMOS
INPUTS
EIA/TIA-232
OUTPUTS
CMOS
OUTPUTS
EIA/TIA-232
INPUTS*
T1
T2
R1
R2
+
+
+
0.1µF
10V
0.1µF
10V
GND
ADM3222
C3
0.1µF
6.3V
+3.3
V
INPUT
+3.3V TO +6.6V
VOLTAGE
DOUBLER
+6.6V TO –6.6V
VOLTAGE
INVERTER
C5
0.1µF
+
C4
0.1µF
10V
+
*INTERNAL 5kΩ PULL-DOWN RESISTOR
ON EACH RS-232 INPUT
00071-002
Figure 2.
C1+
C2+
C1–
C2–
V
CC
V–
V+
T1
IN
T1
OUT
T2
IN
T2
OUT
R1
OUT
R1
IN
R2
OUT
DD
R2
IN
SD
CMOS
INPUTS
EIA/TIA-232
OUTPUTS
CMOS
OUTPUTS
EIA/TIA-232
INPUTS*
T1
T2
R1
R2
+
+
0.1µF
10V
0.1µF
10V
GND
ADM1385
+3.3V INPUT
+3.3V TO +6.6V
VOLTAGE
DOUBLER
+6.6V TO –6.6V
VOLTAGE
INVERTER
C5
0.1µF
+
+
+
*INTERNAL 5kΩ PULL-DOWN RESISTOR
ON EACH RS-232 INPUT
00071-003
C3
0.1µF
10V
C4
0.1µF
10V
Figure 3.