19-1949; Rev 0; 1/01
±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
________________General Description
The MAX3384E 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 MAX3384E has two receivers and two drivers. It
features a 1µA shutdown mode that reduces power con-
sumption and extends battery life in portable systems.
The MAX3384E is available in a space-saving SSOP
package in either the commercial (0°C to +70°C) or
extended temperature (-40°C to +85°C) 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
o
250kbps Guaranteed Data Rate
o
250µs Time to Exit Shutdown with 3kΩ Load on V+
o
6V/µs Guaranteed Slew Rate
o
Transmitter and Receiver Outputs High
Impedance in Shutdown
o
Meets EIA/TIA-232 Specifications Down to 3.0V
MAX3384E
Ordering Information
PART
MAX3384ECAP
MAX3384ECWN
MAX3384EEAP
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
________________________Applications
Hand-Held Equipment
Peripherals
Printers
Battery-Powered
Equipment
PDAs
+3.3V
C
BYPASS
C1
0.1µF
Typical Operating Circuit
C1+
C1-
V
CC
V+
C3
*
0.1µF
C4
0.1µF
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
TTL/CMOS
INPUTS
C2
0.1µF
MAX3384E
C2+
C2-
T1IN
T1OUT
RS-232
OUTPUTS
T2IN
T2OUT
V-
MAX3384E
16 R1IN
15 R1OUT
14 T1IN
13 T2IN
12 R2OUT
11 N.C.
TTL/CMOS
OUTPUTS
R1OUT
R1IN
5k
RS-232
INPUTS
R2OUT
R2IN
5k
GND
SHDN
SSOP
Pin Configurations continued at end of data sheet.
†
C.
*
C3 CAN BE RETURNED TO EITHER V
CC
OR GROUND.
NOTE: SEE TABLE 2 FOR CAPACITOR SELECTION
________________________________________________________________
Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
MAX3384E
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ..............................................................-0.3V to +6V
Continuous Power Dissipation (T
A
= +70°C)
V+ to GND (Note 1) ..................................................-0.3V to +7V
20-Pin SSOP (derate 8.00mW/°C above +70°C) ..........640mW
V- to GND (Note 1) ...................................................+0.3V to -7V
18-Pin SO (derate 9.52mW/°C above +70°C)...............762mW
V+ + |V-| (Note 1) .................................................................+13V
Operating Temperature Ranges
Input Voltages
MAX3384ECAP ....................................................0°C to +70°C
T_IN,
SHDN
to GND ..............................................-0.3V to +6V
MAX3384ECWN ...................................................0°C to +70°C
R_IN to GND .....................................................................±25V
MAX3384EEAP .................................................-40°C to +85°C
Output Voltages
Junction Temperature ........................................................150°C
T_OUT to GND...............................................................±13.2V
Storage Temperature Range .............................-65°C to +150°C
R_OUT .....................................................-0.3V to (V
CC
+ 0.3V)
Lead Temperature (soldering, 10s) .................................+300°C
Maximum Current into T_OUT ........................................±100mA
Short-Circuit Duration, T_OUT to GND.......................Continuous
Note 1:
V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
CC
= +3V to +5.5V, for tests at 3.3V ±10%, C1–C4 = 0.1µF; for tests at +5V ±10%, C1 = 0.047µF, C2–C4 = 0.33µF;
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Supply Current
Shutdown Supply Current
LOGIC INPUTS
Input Logic Threshold Low
Input Logic Threshold High
Transmitter Input Hysteresis
Input Leakage Current
RECEIVER OUTPUTS
Output Leakage Current
Output Voltage Low
Output Voltage High
RECEIVER INPUTS
Input Voltage Range
Input Threshold Low
Input Threshold High
Input Hysteresis
Input Resistance
2
T
A
= +25°C
3
T
A
= +25°C
T
A
= +25°C
V
CC
= +3.3V
V
CC
= +5V
V
CC
= +3.3V
V
CC
= +5V
-25
0.6
0.8
1.2
1.5
1.5
1.8
0.5
5
7
2.4
2.4
+25
V
V
V
V
kΩ
R_OUT, receivers disabled
I
OUT
= 1.6mA
I
OUT
= -1.0mA
V
CC
-
0.6
V
CC
-
0.1
±0.05
±10
0.4
µA
V
V
T_IN,
SHDN
T_IN,
SHDN
T_IN,
SHDN
V
CC
= +3.3V
V
CC
= +5V
2.0
2.4
0.5
±0.01
±1
0.8
V
V
V
µA
SHDN
= V
CC
, no load
SHDN
= GND
CONDITIONS
MIN
TYP
0.3
1
MAX
1
10
UNITS
mA
µA
DC CHARACTERISTICS
(V
CC
= +3.3V or +5V, T
A
= +25°C)
_______________________________________________________________________________________
±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3V to +5.5V, for tests at 3.3V ±10%, C1–C4 = 0.1µF; for tests at +5V ±10%, C1 = 0.047µF, C2–C4 = 0.33µF;
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
TRANSMITTER OUTPUTS
Output Voltage Swing
Output Resistance
Output Short-Circuit Current
Output Leakage Current
ESD PROTECTION
Human Body Model
R_IN, T_OUT
IEC1000-4-2 Air Discharge
IEC1000-4-2 Contact Discharge
±15
±15
±8
kV
V
CC
= 0 or +3V to +5.5V, V
OUT
= ±12V, transmitters dis-
All transmitter outputs loaded with 3kΩ to ground
V
CC
= 0, transmitter output = ±2V
±5
300
±5.4
10M
±60
±25
V
Ω
mA
µA
CONDITIONS
MIN
TYP
MAX
UNITS
MAX3384E
TIMING CHARACTERISTICS
(V
CC
= +3V to +5.5V, for tests at 3.3V ±10%, C1–C4 = 0.1µF; for tests at +5V ±10%, C1 = 0.047µF, C2–C4 = 0.33µF; T
A
= T
MIN
to
T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Maximum Data Rate
Receiver Propagation Delay
Receiver Output Enable Time
Receiver Output Disable Time
Time to Exit Shutdown
Transmitter Skew
Receiver Skew
t
PHL
- t
PLH
|
t
PHL
- t
PLH
|
V
CC
= +3.3V,
T
A
= +25°C,
R
L
= 3kΩ to 7kΩ,
measured from +3V
to -3V or -3V to +3V
C
L
= 150pF to
1000pF
C
L
= 150pF to
2500pF
6
4
t
PHL
t
PLH
SYMBOL
CONDITIONS
R
L
= 3kΩ, C
L
= 1000pF,
one transmitter switching
Receiver input to receiver output,
C
L
= 150pF
SHDN
from GND to V
CC
SHDN
from V
CC to
GND
V
OUT
≥
+3.7V, R
LOAD
at V+ = 3kΩ
(Note 2)
MIN
250
0.15
0.15
200
200
250
100
50
30
V/µs
30
TYP
MAX
UNITS
kbps
µs
ns
ns
µs
ns
ns
Transition-Region Slew Rate
Note 2:
Transmitter skew is measured at the transmitter zero cross points.
_______________________________________________________________________________________
3
±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
MAX3384E
__________________________________________Typical Operating Characteristics
(V
CC
= +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ and C
L
, T
A
= +25°C, unless otherwise noted.)
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
TRANSMITTER OUTPUT VOLTAGE (V)
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
0
MAX3384E-01
SLEW RATE vs. LOAD CAPACITANCE
MAX3884E-02
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
40
SUPPLY CURRENT (mA)
35
250kbps
30
25
20
15
10
20kbps
120kbps
T1 TRANSMITTING AT 250kbps
T2 TRANSMITTING AT 15.6kbps
MAX3884E-03
16
14
12
SLEW RATE (V/µs)
10
8
6
4
+SLEW
-SLEW
45
V
OUT+
T1 TRANSMITTING AT 250kbps
T2 TRANSMITTING AT 15.6kbps
V
OUT-
2
FOR DATA RATES UP TO 250kbps
0
5
0
4000
5000
0
1000
2000
3000
4000
5000
1000
2000
3000
4000
5000
0
1000
2000
3000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
______________________________________________________________ Pin Description
PIN
SO
1
2
3
4
5
6
7
8, 15
9, 14
10, 13
11, 12
16
17
18
SSOP
1, 10, 11
2
3
4
5
6
7
8, 17
9, 16
12, 15
13, 14
18
19
20
NAME
N.C.
C1+
V+
C1-
C2+
C2-
V-
T_OUT
R_IN
R_OUT
T_IN
GND
V
CC
SHDN
FUNCTION
No Connection. Not internally connected.
Positive terminal of the voltage-doubler charge-pump capacitor.
+5.5V generated by the charge pump.
Negative terminal of the voltage-doubler charge-pump capacitor.
Positive terminal of inverting charge-pump capacitor.
Negative terminal of inverting charge-pump capacitor.
-5.5V generated by the charge pump.
RS-232 Transmitter Outputs. High Z when
SHDN
is low.
RS-232 Receiver Inputs
TTL/CMOS Receiver Outputs. High Z when
SHDN
is low.
TTL/CMOS Transmitter Inputs
Ground
+3.0V to +5.5V Supply Voltage. Connect a 0.1µF capacitor to GND.
Active-Low Shutdown-Control Input. Drive low to shut down transmitters, receivers and
charge pumps.
4
_______________________________________________________________________________________
±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
MAX3384E
V
CC
0.1µF
V
CC
V
CC
0.1µF
V
CC
C1+
C1
C1-
C2+
C2
C2-
T_ IN
V+
C3
3kΩ
C1
C1+
C1-
C2+
C4
C2
C2-
T_ IN
V+
C3
3kΩ
MAX3384E
V-
MAX3384E
V-
C4
T_ OUT
T_ OUT
R_ OUT
R_ IN
R_ OUT
R_ IN
5kΩ
V
CC
SHDN
GND
3kΩ
2500pF
V
CC
SHDN
GND
5kΩ
7kΩ
150pF
MINIMUM SLEW-RATE TEST CIRCUIT
Figure 1. Slew-Rate Test Circuits
MAXIMUM SLEW-RATE TEST CIRCUIT
_______________Detailed Description
Dual Charge-Pump Voltage Converter
The MAX3384E’s internal power supply consists of a
regulated dual charge pump that provides output volt-
ages of +5.5V (doubling charge pump) and -5.5V
(inverting charge pump), over the +3.0V to +5.5V V
CC
range. The charge pump operates in discontinuous
mode; if the output voltages are less than 5.5V, the
charge pump is enabled, and if the output voltages
exceed 5.5V, the charge pump is disabled. Each
charge pump requires a flying capacitor (C1, C2) and a
reservoir capacitor (C3, C4) to generate the V+ and V-
supplies (Figure 1).
The MAX3384E’s transmitters are disabled and the out-
puts are forced into a high-impedance state when the
device is in shutdown (SHDN = GND). The MAX3384E
permits the outputs to be driven up to ±12V in shut-
down.
The transmitter inputs do not have pullup resistors.
Connect unused inputs to GND or V
CC
.
RS-232 Receivers
The receivers convert RS-232 signals to CMOS-logic
output levels (Table 1). The receiver outputs are forced
into a high-impedance state when the device is in shut-
down (SHDN = GND). This allows a single UART to
multiplex between different protocols.
RS-232 Transmitters
The transmitters are inverting level translators that con-
vert CMOS-logic levels to ±5.0V EIA/TIA-232 levels.
The MAX3384E transmitters guarantee a 250kbps data
rate with worst-case loads of 3kΩ in parallel with 1000pF,
providing compatibility with PC-to-PC communication
software (such as LapLink™). Transmitters can be paral-
leled to drive multiple receivers or mice.
Laplink is a trademark of Traveling Software.
Shutdown Mode
Supply current falls to less than 1µA in shutdown mode
(SHDN = low). When shut down, the device’s charge
Table 1. Shutdown Truth Table
SHDN
0
1
T_OUT
High-Z
Active
R_OUT
High-Z
Active
5
_______________________________________________________________________________________
