Low Power, 3.3 V, RS-232
Line Drivers/Receivers
ADM3202/ADM3222/ADM1385
FEATURES
FUNCTIONAL BLOCK DIAGRAMS
+3.3V INPUT
460 kbps data rate
Specified at 3.3 V
+3.3V TO +6.6V
VOLTAGE
+
C1+
C1–
V
CC
+
+
0.1µF
10V
C3
+
C5
0.1µF
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
0.1µF
6.3V
DOUBLER
+6.6V TO –6.6V
VOLTAGE
INVERTER
C2+
C2–
V–
0.1µF
10V
C4
+
0.1µF
10V
T1
T2
T1
T1
IN
OUT
OUT
CMOS
EIA/TIA-232
OUTPUTS
INPUTS
T2
T2
IN
R1
R1
R1
R2
OUT
OUT
IN
IN
CMOS
OUTPUTS
EIA/TIA-232
INPUTS*
R2
R2
15 kV: air gap discharge
ADM3202
GND
*INTERNAL 5kΩ PULL-DOWN RESISTOR
ON EACH RS-232 INPUT
APPLICATIONS
Figure 1.
General-purpose RS-232 data link
Portable instruments
Printers, palmtop computers, PDAs
+3.3V INPUT
+3.3V TO +6.6V
+
C1+
C1–
V
CC
+
0.1µF
10V
C3
+
VOLTAGE
DOUBLER
C5
0.1µF
V+
0.1µF
6.3V
+6.6V TO –6.6V
VOLTAGE
INVERTER
C2+
C2–
V–
+
0.1µF
10V
C4
+
GENERAL DESCRIPTION
0.1µF
10V
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.
T1
T2
T1
T1
IN
OUT
CMOS
EIA/TIA-232
OUTPUTS
INPUTS
T2
T2
IN
OUT
R1
R2
R1
R1
R2
OUT
OUT
IN
IN
CMOS
OUTPUTS
EIA/TIA-232
INPUTS*
R2
The ADM3202/ADM3222/ADM1385 parts conform to the
EIA-232E and CCITT V.28 specifications and operate at data
rates up to 460 kbps.
EN
SD
ADM3222
GND
*INTERNAL 5kΩ PULL-DOWN RESISTOR
ON EACH RS-232 INPUT
Four external 0.1 μF charge pump capacitors are used for the
voltage doubler/inverter, permitting operation from a single
3.3 V supply.
Figure 2.
+3.3V INPUT
+3.3V TO +6.6V
VOLTAGE
DOUBLER
+
C1+
C1–
V
CC
+
0.1µF
10V
C5
0.1µF
The ADM3222 contains additional enable and shutdown
+
C3
0.1µF
10V
V+
EN
circuitry. The
SD
input can be used to three-state the receiver
+6.6V TO –6.6V
VOLTAGE
INVERTER
C2+
C2–
V–
+
0.1µF
10V
C4
+
0.1µF
outputs. The
input is used to power down the charge pump
10V
and transmitter outputs, reducing the quiescent current to less
than 0.5 μA. The receivers remain enabled during shutdown
T1
T2
T1
T1
IN
OUT
CMOS
INPUTS
EIA/TIA-232
OUTPUTS
T2
T2
IN
OUT
EN
unless disabled using
.
R1
R2
R1
R1
R2
OUT
OUT
IN
IN
The ADM1385 contains a driver disable mode and a complete
shutdown mode.
CMOS
OUTPUTS
EIA/TIA-232
INPUTS*
R2
DD
SD
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.
ADM1385
GND
*INTERNAL 5kΩ PULL-DOWN RESISTOR
ON EACH RS-232 INPUT
Figure 3.
Rev. E
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