19-1437; Rev 1; 10/99
±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
________________General Description
The MAX3385E is a 3V-powered EIA/TIA-232 and
V.28/V.24 communications interface with low power
requirements, high data-rate capabilities, and en-
hanced electrostatic discharge (ESD) protection. All
transmitter outputs and receiver inputs are protected to
±15kV using IEC 1000-4-2 Air-Gap Discharge, ±8kV
using IEC 1000-4-2 Contact Discharge, and ±15kV
using the Human Body Model.
The transceiver has a proprietary low-dropout transmit-
ter output stage, delivering true RS-232 performance
from a +3.0V to +5.5V supply with a dual charge pump.
The charge pump requires only four small 0.1µF capac-
itors for operation from a +3.3V supply. Each device is
guaranteed to run at data rates of 250kbps while main-
taining RS-232 output levels.
The MAX3385E has two receivers and two drivers. It
features a 1µA shutdown mode that reduces power con-
sumption and extends battery life in portable systems.
Its receivers can remain active in shutdown mode,
allowing external devices such as modems to be moni-
tored using only 1µA supply current.
The MAX3385E is available in a space-saving SSOP
package in either the commercial (0°C to +70°C) or
extended-industrial (-40°C to +85°C) temperature range.
____________________________Features
o
ESD Protection for RS-232 I/O Pins
±15kV—Human Body Model
±8kV—IEC 1000-4-2, Contact Discharge
±15kV—IEC 1000-4-2, Air-Gap Discharge
o
Latchup Free
o
300µA Supply Current
o
1µA Low-Power Shutdown with Receivers Active
o
250kbps Guaranteed Data Rate
o
250µs Time to Exit Shutdown with 3kΩ Load on V+
o
6V/µs Guaranteed Slew Rate
o
Meets EIA/TIA-232 Specifications Down to 3.0V
MAX3385E
†
Ordering Information
PART
MAX3385ECAP
MAX3385ECWN
MAX3385EEAP
TEMP. RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
20 SSOP
18 SO
20 SSOP
Typical Operating Circuit
+3.3V
C
BYPASS
C1
0.1µF
C1+
C1-
________________________Applications
Hand-Held Equipment
Peripherals
Printers
Battery-Powered
Equipment
V
CC
V+
C3
*
0.1µF
C4
0.1µF
MAX3385E
Pin Configurations
TOP VIEW
N.C. 1
C1+ 2
V+ 3
C1- 4
C2+ 5
C2- 6
V- 7
T2OUT 8
R2IN 9
N.C. 10
20 SHDN
19 V
CC
18 GND
17 T1OUT
C2
0.1µF
C2+
C2-
T1IN
V-
T1OUT
RS-232
OUTPUTS
TTL/CMOS
INPUTS
T2IN
T2OUT
MAX3385E
R1OUT
R1IN
5k
RS-232
INPUTS
16 R1IN
15 R1OUT
14 T1IN
13 T2IN
12 R2OUT
GND
TTL/CMOS
OUTPUTS
R2OUT
R2IN
5k
SHDN
11 N.C.
SSOP
Pin Configurations continued at end of data sheet.
*
C3 CAN BE RETURNED TO EITHER V
CC
OR GROUND.
NOTE: SEE TABLE 2 FOR CAPACITOR SELECTION
†
Covered by U.S. Patent numbers 4,636,930; 4,679,134; 4,777,577; 4,797,899; 4,809,152; 4,897,774; 4,999,761; and other patents pending.
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
