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General Description
The MAX3387E 3V powered EIA/TIA-232 and V.28/V.24
is a communications interface with low power require-
ments, high data-rate capabilities, and enhanced elec-
trostatic discharge (ESD) protection. The MAX3387E
has three receivers and three transmitters. All RS-232
inputs and outputs are protected to ±15kV using the
IEC 1000-4-2 Air-Gap Discharge method, ±8kV using
the IEC 1000-4-2 Contact Discharge method, and
±15kV using the Human Body Model.
A proprietary low-dropout transmitter output stage
enables 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 capacitors for
operation from a +3.3V supply. The MAX3387E is capa-
ble of running at data rates up to 250kbps while main-
taining RS-232 compliant output levels.
The MAX3387E has a unique V
L
pin that allows interop-
eration in mixed-logic voltage systems. Both input and
output logic levels are pin programmable through the
V
L
pin. The MAX3387E is available in a space-saving
TSSOP package.
Applications
Subnotebook/Palmtop Computers
PDAs and PDA Cradles
Cell Phone Data Cables
Battery-Powered Equipment
Hand-Held Equipment
Peripherals
Features
o
V
L
Pin for Compatibility with Mixed-Voltage
Systems
o
±15kV ESD Protection on Rx Inputs and Tx Outputs
o
Low 300µA Supply Current
o
Guaranteed 250kbps Data Rate
o
1µA AutoShutdown PlusTM with Receivers Active
o
Meets EIA/TIA-232 Specifications Down to 3.0V
MAX3387E
3V, ±15kV ESD-Protected, AutoShutdown Plus
RS-232 Transceiver for PDAs and Cell Phones
________________________________________________________________
Maxim Integrated Products
1
24
23
22
21
20
19
18
17
1
2
3
4
5
6
7
8
FORCEOFF
V
CC
GND
T1OUT
C2+
C1-
V+
C1+
TOP VIEW
T2OUT
T3OUT
R1IN
R2IN
T2IN
T1IN
V-
C2-
16
15
14
13
9
10
11
12
R3IN
V
L
R1OUT
R2OUT
R3OUT
FORCEON
T3IN
INVALID
TSSOP
MAX3387E
C1
0.1
µ
F
C2
0.1
µ
F
MAX3387E
R2OUT
13
R1OUT
14
R2IN 17
GND
22
RS-232
OUTPUTS
TTL/CMOS
INPUTS
T2IN
8
T1IN
7
C2-
5
C2+
4
C1-
3
C1+
1
R1IN 18
T2OUT 20
T1OUT 21
V-
6
V+
2
V
CC
V
L
C4
0.1
µ
F
23
15
C
BYPASS
+3.3V
T3IN
10
T3OUT 19
RS-232
INPUTS
TTL/CMOS
OUTPUTS
C3
0.1
µ
F
5k
5k
V
L
V
L
R3OUT
12
R3IN 16
5k
V
L
FORCEOFF
24
INVALID
9
11
FORCEON
Typical Operating Circuit
19-1561; Rev 1; 10/99
Pin Configuration
Ordering Information
AutoShutdown Plus is a trademark of Maxim Integrated Products.
PART
MAX3387ECUG
MAX3387EEUG
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
24 TSSOP
24 TSSOP
MAX3387E
3V, ±15kV ESD-Protected, AutoShutdown Plus
RS-232 Transceiver for PDAs and Cell Phones
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(V
CC
= V
L
= +3.0V to +5.5V; C1C4 = 0.1µF, tested at +3.3V ±10%; C1 = 0.047µF, C2C4 = 0.33µF, tested at +5.0V ±10%; T
A
=
T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= V
L
= +3.3V, T
A
= +25°C.)
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.
Note 1:
V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
V
CC
to GND ..............................................................-0.3V to +6V
V
L
to GND...................................................-0.3V to (V
CC
+ 0.3V)
V+ to GND ................................................................-0.3V to +7V
V- to GND .................................................................+0.3V to -7V
V+ +
V-
(Note 1) .............................................................. +13V
Input Voltages
T_IN, FORCEON, FORCEOFF to GND ..................-0.3V to +6V
R_IN to GND .....................................................................±25V
Output Voltages
T_OUT to GND...............................................................±13.2V
R_OUT........................................................-0.3V to (V
L
+ 0.3V)
Short-Circuit Duration T_OUT to GND........................Continuous
Continuous Power Dissipation (T
A
= +70°C)
24-Pin TSSOP (derate 7.8mW/°C above +70°C) ..........625mW
Operating Temperature Ranges
MAX3387ECUG ...................................................0°C to +70°C
MAX3387EEUG ................................................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
I
OUT
= 1.6mA
All R_IN idle, FORCEON = GND,
FORCEOFF = V
CC
, all T_IN idle
T_IN, FORCEON, FORCEOFF
T_IN, FORCEON,
FORCEOFF
FORCEOFF = FORCEON = V
CC
, no load
CONDITIONS
V
0.4
Output Voltage Low
µA
±0.01
±1
Input Leakage Current
V
0.5
Transmitter Input Hysteresis
V
0.9
Input Logic Threshold High
1.4
2.0
µA
1.0
10
Supply Current, AutoShutdown
Plus
2.4
V
0.8
0.3
1
mA
Supply Current
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
V
L
= 5.0V
V
L
= 3.3V
V
L
= 2.5V
V
L
= 1.8V
I
OUT
= -1mA
V
V
L
- V
L
-
0.6
0.1
Output Voltage High
V
L
= 3.3V or 5.0V
T_IN, FORCEON,
FORCEOFF
0.6
Input Logic Threshold Low
V
L
= 2.5V
V
-25
+25
Input Voltage Range
T
A
= +25°C
V
0.8
1.5
Input Threshold Low
V
L
= 5.0V
V
L
= 2.5V or 3.3V
0.6
1.2
T
A
= +25°C
V
1.8
2.4
Input Threshold High
V
L
= 5.0V
V
L
= 2.5V or 3.3V
1.5
2.4
DC CHARACTERISTICS
(V
CC
= +3.3V or +5V, T
A
= +25°C)
LOGIC INPUTS
RECEIVER OUTPUTS
RECEIVER INPUTS
MAX3387E
3V, ±15kV ESD-Protected, AutoShutdown Plus
RS-232 Transceiver for PDAs and Cell Phones
_______________________________________________________________________________________
3
DC ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= V
L
= +3.0V to +5.5V; C1C4 = 0.1µF, tested at +3.3V ±10%; C1 = 0.047µF, C2C4 = 0.33µF, tested at +5.0V ±10%; T
A
=
T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= V
L
= +3.3V, T
A
= +25°C.)
AutoShutdown Plus
(FORCEON = GND, FORCEOFF = V
CC)
ESD PROTECTION
TRANSMITTER OUTPUTS
-2.7
Negative threshold
Figure 3a
Positive threshold
Receiver or Transmitter Edge to
Transmitters Shutdown
t
AUTOSHDN
15
30
60
sec
Receiver Positive or Negative
Threshold to INVALID Low
t
INVL
30
V
CC
= 5V, Figure 3b
Receiver or Transmitter Edge to
Transmitters Enabled
t
WU
100
µs
V
CC
= 5V, Figure 3b
µs
V
CC
= 5V, Figure 3b
Receiver Positive or Negative
Threshold to INVALID High
t
INVH
1
µs
INVALID Output Voltage Low
0.4
V
CC
= 5V, Figure 3b
INVALID Output Voltage High
V
L
- 0.6
V
I
OUT
= -1.6mA
V
I
OUT
= -1.0mA
Receiver Input Threshold to
INVALID Output Low
-0.3
0.3
V
Receiver Input Threshold to
INVALID Output High
2.7
V
Figure 3a
R_IN, T_OUT
ESD Protection
±8
kV
IEC 1000-4-2 Contact Discharge method
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
Input Hysteresis
0.5
V
Input Resistance
3
5
7
k
Output Voltage Swing
±5
±5.4
V
Output Resistance
300
10M
Output Short-Circuit Current
±60
mA
Output Leakage Current
±25
µA
±15
±15
CONDITIONS
T
A
= +25°C
All transmitter outputs loaded with 3k
to
ground
V
CC
= V+ = V- = 0, transmitter output = ±2V
V
T_OUT
= 0
V
T_OUT
= ±12V, transmitters disabled;
V
CC
= 0 or 3.0V to 5.5V
Human Body Model
IEC 1000-4-2 Air-Gap Discharge method
TRANSMITTER OUTPUTS
ESD PROTECTION
AutoShutdown Plus
(FORCEON = GND, FORCEOFF = V
CC)
C
L
= 150pF to
1000pF
C
L
= 150pF to
2500pF
V
CC
= 3.3V,
T
A
= +25°C,
R
L
= 3k
to 7k
,
measured from +3V
to -3V or -3V to +3V
R
L
= 3k
, C
L
= 1000pF,
one transmitter switching
(Note 2)
V/µs
4
30
V
T_OUT
> 3.7V
Transition-Region Slew
Rate
Receiver input to receiver output,
C
L
= 150pF
CONDITIONS
6
30
ns
50
t
PHL
- t
PLH
Receiver Skew
ns
100
t
PHL
- t
PLH
Transmitter Skew
µs
100
Time to Exit Shutdown
µs
0.15
t
PLH
Receiver Propagation Delay
kbps
250
Maximum Data Rate
0.15
t
PHL
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
TIMING CHARACTERISTICS
(V
CC
= V
L
= +3V to +5.5V; C1C4 = 0.1µF, tested at +3.3V ±10%; C1 = 0.047µF, C2C4 = 0.33µF, tested at +5.0V ±10%; T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= V
L
= +3.3V, T
A
= +25°C.)
MAX3387E
3V, ±15kV ESD-Protected, AutoShutdown Plus
RS-232 Transceiver for PDAs and Cell Phones
4
_______________________________________________________________________________________
MAX3387E
3V, ±15kV ESD-Protected, AutoShutdown Plus
RS-232 Transceiver for PDAs and Cell Phones
_______________________________________________________________________________________
5
-7.5
-5.0
-2.5
0
2.5
5.0
7.5
0
1000
2000
3000
4000
5000
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3387E-01
LOAD CAPACITANCE (pF)
OUTPUT VOLTAGE (V)
DATA RATE = 250kbps
LOAD = 3k
IN PARALLEL WITH C
L
0
2
4
6
8
10
12
14
16
0
1000
2000
3000
4000
5000
SLEW RATE vs. LOAD CAPACITANCE
MAX3387E-02
LOAD CAPACITANCE (pF)
SLEW RATE (V/µs)
SLEW RATE +
SLEW RATE -
-7.5
-5.0
-2.5
0
2.5
5.0
7.5
0
50
100
150
200
250
TRANSMITTER OUTPUT VOLTAGE
vs. DATA RATE
MAX3387E-03
DATA RATE (kbps)
OUTPUT VOLTAGE (V)
LOAD = 3k
, 1000pF
ONE TRANSMITTER
SWITCHING AT DATA
RATE, OTHER
TRANSMITTERS
AT 1/8 DATA RATE
0
10
20
30
40
50
60
0
1000
2000
3000
4000
5000
SUPPLY CURRENT vs. LOAD CAPACITANCE
MAX3387E-04
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
250kbps
120kbps
20kbps
LOAD = 3k
,
ONE TRANSMITTER
SWITCHING AT DATA
RATE, OTHER
TRANSMITTERS
AT 1/8 DATA RATE
Typical Operating Characteristics
(V
CC
= V
L
= +3.3V, T
A
= +25°C, unless otherwise noted.)
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