19-2403; Rev 0; 8/95
±15kV ESD-Protected, Quad, Low-Power
RS-232 Line Driver
_______________General Description
The MAX1488E quad, low-power line driver is designed
for EIA/TIA-232, EIA/TIA-562, and CCITT V.28 commu-
nications in harsh environments. Each transmitter out-
put is protected against ±15kV electrostatic discharge
(ESD) shocks. The inputs are TTL and CMOS compati-
ble with minimal loading. The outputs feature internally
controlled slew-rate limiting and current limiting. This
device has a guaranteed 120kbps data rate. Power-
supply current is less than 180µA over a ±4.5V to
±13.2V supply voltage range.
The MAX1488E is pin compatible with the MC1488,
MC14C88, SN75188, SN75C188, DS1488, and
DS14C88. It is available in 14-pin plastic DIP and SO
packages.
____________________________Features
o
ESD Protection:
±15kV—Human Body Model
±6kV—IEC801-2, Contact Discharge
±15kV—IEC801-2, Air-Gap Discharge
o
Latchup Free, Even During an ESD Event
o
Low 85µA Supply Current from I
EE
or I
CC
o
Guaranteed 120kbps Data Rate
o
No External Capacitors Required for Slew-Rate
Limiting
o
Pin Compatible with MC1488, MC14C88, SN75188,
SN75C188, DS1488, and DS14C88
MAX1488E
________________________Applications
PC Motherboards
Modems
Interface Data Terminal Equipment (DTE) with
Data Circuit-Terminating Equipment (DCE)
Equipment Meeting IEC1000-4-2
(formerly IEC801-2) or ±15kV ESD Protection
______________Ordering Information
PART
MAX1488ECPD
MAX1488ECSD
MAX1488EC/D
MAX1488EEPD
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
14 Plastic DIP
14 SO
Dice*
14 Plastic DIP
14 SO
MAX1488EESD
-40°C to +85°C
* Dice are specified at T
A
= +25°C.
__________Typical Operating Circuit
__________________Pin Configuration
1
⁄
4
MAX1488E
1
⁄
4
MAX1489E
TOP VIEW
V
EE
1
TTL/CMOS
LOGIC
INTERCONNECTING
CABLE
TTL/CMOS
LOGIC
INPUT A 2
OUTPUT A 3
INPUT B1 4
14 V
CC
MAX1488E
13 INPUT D1
12 INPUT D2
11 OUTPUT D
10 INPUT C1
9
8
INPUT C2
OUTPUT C
1
⁄
4
MAX1489E
SIGNAL GROUND
1
⁄
4
MAX1488E
INPUT B2 5
OUTPUT B 6
GND 7
PC
MOTHERBOARD
(DTE)
MODEM
(DCE)
DIP/SO
________________________________________________________________
Maxim Integrated Products
1
Call toll free 1-800-998-8800 for free samples or literature.
±15kV ESD-Protected, Quad, Low-Power
RS-232 Line Driver
MAX1488E
ABSOLUTE MAXIMUM RATINGS
Positive Supply Voltage (V
CC
) .............................................+14V
Negative Supply Voltage (V
EE
) .............................................-14V
Input Voltage (V
IN
) .................................................-0.3V to +15V
Driver Output Voltage ..........................................................±15V
Continuous Power Dissipation (T
A
= +70°C)
Plastic DIP (derate 10.00mW/°C above +70°C) ..........800mW
SO (derate 8.7mW/°C above +70°C) ...........................695mW
Operating Temperature Ranges
MAX1488EC_D ...................................................0°C to +70°C
MAX1488EE_D ................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°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.
ELECTRICAL CHARACTERISTICS
(V
CC
= 4.5V to 13.2V, V
EE
= -4.5V to -13.2V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DC CHARACTERISTICS
V
CC
= -V
EE
= 5.0V, R
L
= 3kΩ
V
CC
= -V
EE
= 6.5V, R
L
= 3kΩ
V
CC
= -V
EE
= 12.0V, R
L
= 3kΩ
V
CC
= -V
EE
= 13.2V, R
L
= open
V
CC
= -V
EE
= 5.0V, R
L
= 3kΩ
V
CC
= -V
EE
= 6.5V, R
L
= 3kΩ
V
CC
= -V
EE
= 12.0V, R
L
= 3kΩ
V
CC
= -V
EE
= 13.2V, R
L
= open
3.7
5
10
4.0
5.4
10.5
-4.5
-5.8
-10.8
-13.2
4.5
-13.2
No load
No load
Output shorted to ground (Note 1)
-180
±4
2.0
0.8
0
V
CC
= V
EE
= 0V
I
V
O
I
≤
2.0V
V
CC
= 4.5V, V
EE
= -4.5V, C
L
= 50pF
t
PLH
V
CC
= 9.0V, V
EE
= -9.0V, C
L
= 50pF
V
CC
= 12.0V, V
EE
= -12.0V, C
L
= 50pF
Output Propagation Delay,
High to Low
Propagation Delay Skew,
V
CC
= 4.5V, V
EE
= -4.5V, C
L
= 50pF
t
PHL
V
CC
= 9.0V, V
EE
= -9.0V, C
L
= 50pF
V
CC
= 12.0V, V
EE
= -12.0V, C
L
= 50pF
V
CC
= 4.5V, V
EE
= -4.5V, C
L
= 50pF
t
SK
V
CC
= 9.0V, V
EE
= -9.0V, C
L
= 50pF
V
CC
= 12.0V, V
EE
= -12.0V, C
L
= 50pF
Human Body Model
ESD Protection
IEC-1000-4-2 (Contact Discharge)
IEC-1000-4-2 (Air-Gap Discharge)
2
300
2.4
2.8
3.1
2.1
2.4
2.6
0.25
0.42
0.42
±15
±6
±15
kV
µs
3.5
3.9
4.2
4.5
5.1
5.4
µs
µs
±2
85
-85
±20
±45
13.2
-3.7
-5
-10
13.2
-4.5
180
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Output Voltage High
V
OH
V
Output Voltage Low
V
OL
V
CC
V
EE
I
CC
I
EE
I
OS
V
IH
V
IL
I
IN1
R
O
V
Operating Voltage Range
Positive Supply Current
Negative Supply Current
Output Short-Circuit Current
Input High Voltage
Input Low Voltage
Input Current
Output Resistance
V
µA
µA
mA
V
V
µA
Ω
TIMING CHARACTERISTICS
(see Figure 1)
Output Propagation Delay,
Low to High
I
t
PLH
- t
PHL
I
ESD CHARACTERISTICS
_______________________________________________________________________________________
±15kV ESD-Protected, Quad, Low-Power
RS-232 Line Driver
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 4.5V to 13.2V, V
EE
= -4.5V to -13.2V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
t
R1
Output Rise Time
t
R2
t
F1
Output Fall Time
t
F2
CONDITIONS
C
L
= 1500pF, R
L
= 5kΩ,
V
OUTPUT_
from -3.3V to 3.3V
C
L
= 1500pF, R
L
= 5kΩ,
V
OUTPUT_
from -3.0V to 3.0V
C
L
= 1500pF, R
L
= 5kΩ,
V
OUTPUT_
from -3.3V to 3.3V
C
L
= 1500pF, R
L
= 5kΩ,
V
OUTPUT_
from -3.0V to 3.0V
C
L
= 15pF to 2500pF, R
L
= 3kΩ to 7kΩ,
V
CC
= 12V, V
EE
= -12V, T
A
= +25°C,
V
OUTPUT_
from -3.0V to 3.0V
C
L
= 15pF to 2500pF, R
L
= 3kΩ to 7kΩ,
V
CC
= 12V, V
EE
= -12V, T
A
= +25°C
4
MIN
TYP
850
ns
740
860
ns
765
MAX
UNITS
MAX1488E
Output Slew Rate
SR
30
V/µs
Guaranteed Data Rate
120
kbps
Note 1:
The I
OS
value is for one output at a time. If more than one output is shorted simultaneously, damage may occur.
__________________________________________Typical Operating Characteristics
(V
CC
= 12V, V
EE
= -12V, T
A
= +25°C, unless otherwise noted.)
OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
MAX1488E TOC-1
SLEW RATE vs.
LOAD CAPACITANCE
MAX1488E TOC-2
OUTPUT VOLTAGE
vs. TEMPERATURE
V
OH
@ V
CC
= -V
EE
= 12V
10
OUTPUT VOLTAGE (V)
5
0
V
OL
@ V
CC
= -V
EE
= 4.5V
-5
-10
-15
V
OL
@ V
CC
= -V
EE
= 12V
R
L
= 3kΩ
-40 -20
0
20
40
60
80
100
V
OH
@ V
CC
= -V
EE
= 4.5V
MAX1488E TOC-3
15
R
L
= 5kΩ
10
OUTPUT VOLTAGE (V)
V
OH
5
0
-5
V
OL
-10
-15
4
5
6
7
8
R
L
= 3kΩ
R
L
= 5kΩ
R
L
= 3kΩ
11
R
L
= 3kΩ
10
SLEW RATE (V/µs)
9
8
7
FALLING EDGE
6
5
4
3
0
500
1000 1500
2000
RISING EDGE
15
9 10 11 12 13 14
2500 3000
V
CC
AND -V
EE
SUPPLIES (V)
LOAD CAPACITANCE (pF)
TEMPERATURE (°C)
_______________________________________________________________________________________
3
±15kV ESD-Protected, Quad, Low-Power
RS-232 Line Driver
MAX1488E
_____________________Pin Description
PIN
1
2, 4, 5, 9,
10, 12, 13
3, 6, 8, 11
7
14
NAME
V
EE
INPUT_
OUTPUT_
GND
V
CC
FUNCTION
-4.5V to -13.2V Supply Voltage Input
Driver Inputs
Driver Outputs
Ground
+4.5V to +13.2V Supply Voltage Input
t
F2
t
F1
3.3V
3.0V
V
OUT
-3.0V
-3.3V
0V
DRIVER
INPUT
0V
3.0V
1.5V
T
PHL
T
PLH
V
OH
_______________Detailed Description
The MAX1488E provides ±15kV of ESD protection when
operating or when powered down. After an ESD event,
the MAX1488E will not latch up. Internal slew-rate-limit-
ing circuitry eliminates the need for external capacitors.
The MAX1488E has a guaranteed 120kbps data rate.
t
R2
V
OL
t
R1
Outputs
Tables 1 and 2 describe the output states. The output
voltage level is affected by both the load current and
supply voltage, and is stable over temperature. Refer to
the
Typical Operating Characteristics
to see how the
output voltage varies with supply voltage, load capaci-
tance, and temperature.
SIGNAL
GENERATOR
R
L
C
L
Figure 1. Slew-Rate Test Circuit and Timing Diagram
Table 1. Driver A Functions
INPUT A
H
L
OUTPUTA
L
H
operation. Maxim’s engineers developed state-of-the-
art structures to protect these pins against ESD of
±15kV, without damage. After an ESD event, the
MAX1488E keeps working without latchup.
ESD protection can be tested in various ways; the
transmitter outputs are characterized for protection to
the following:
1) ±15kV using the Human Body Model
2) ±6kV using the Contact-Discharge Method specified
in IEC1000-4-2 (formerly IEC801-2)
3) ±15kV using the Air-Gap Method specified in
IEC1000-4-2 (formerly IEC801-2).
Table 2. Driver B–D Functions
INPUT_1
H
L
INPUT_2
H
X
OUTPUT_
L
H
X
L
H
Inputs
The driver inputs determine the driver output states
(Tables 1 and 2). Driver inputs B, C, and D have two
inputs.
Connect unused inputs to ground or V
CC
.
ESD Test Conditions
ESD performance depends on a number of conditions.
Contact Maxim for a reliability report that documents
test setup, methodology, and results.
Human Body Model
Figure 2a shows the Human Body Model, and Figure
2b shows the current waveform it generates when dis-
charged into a low impedance. This model consists of
a 100pF capacitor charged to the ESD voltage of inter-
est, which is then discharged into the test device
through a 1.5kΩ resistor.
±15kV ESD Protection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electro-
static discharges encountered during handling and
assembly. The MAX1488E driver outputs have extra
protection against static electricity found in normal
4
_______________________________________________________________________________________
±15kV ESD-Protected, Quad, Low-Power
RS-232 Line Driver
MAX1488E
R
C
1M
CHARGE-CURRENT
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
SOURCE
R
D
1500Ω
DISCHARGE
RESISTANCE
DEVICE
UNDER
TEST
HIGH-
VOLTAGE
DC
SOURCE
R
C
50M to 100M
CHARGE-CURRENT
LIMIT RESISTOR
R
D
330Ω
DISCHARGE
RESISTANCE
DEVICE
UNDER
TEST
Cs
100pF
STORAGE
CAPACITOR
Cs
150pF
STORAGE
CAPACITOR
Figure 2a. Human Body ESD Test Model
Figure 3a. IEC1000-4-2 ESD Test Model
I
P
100%
90%
AMPERES
36.8%
10%
0
0
t
RL
TIME
Ir
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
I
PEAK
I
100%
90%
10%
t
DL
CURRENT WAVEFORM
t
r
= 0.7ns to 1ns
30ns
60ns
t
Figure 2b. Human Body Model Current Waveform
Figure 3b. IEC1000-4-2 ESD Generator Current Waveform
IEC1000-4-2
The IEC1000-4-2 standard covers ESD testing and per-
formance of finished equipment; it does not specifically
refer to integrated circuits. The MAX1488E helps you
design equipment that meets Level 4 (the highest level)
of IEC1000-4-2, without additional ESD-protection com-
ponents.
The major difference between tests done using the
Human Body Model and IEC1000-4-2 is higher peak
current in IEC1000-4-2. Because series resistance is
lower in the IEC1000-4-2 ESD test model (Figure 3a),
the ESD withstand voltage measured to this standard is
generally lower than that measured using the Human
Body Model. Figure 3b shows the current waveform for
the ±6kV IEC1000-4-2 Level 4 ESD Contact-Discharge
test.
The Air-Gap test involves approaching the device with
a charged probe. The Contact-Discharge method con-
nects the probe to the device before the probe is ener-
gized.
Machine Model
The Machine Model for ESD testing uses a 200pF stor-
age capacitor and zero-discharge resistance. Its objec-
tive is to mimic the stress caused by contact that
occurs with handling and assembly during manufactur-
ing. Of course, all pins (not just RS-232 inputs and out-
puts) require this protection during manufacturing.
Therefore, the Machine Model is less relevant to the I/O
ports than the Human Body Model and IEC1000-4-2.
__________Applications Information
Use proper layout to ensure other devices on your
board are not damaged in an ESD strike. Currents as
high as 60A can instantaneously pass into the ground,
so it is important to minimize the ground-lead return
path to the power supply. A separate return path to the
power supply is recommended. Trace widths should be
greater than 40 mils. V
CC
and V
EE
must be bypassed
with 0.1µF capacitors as close to the part as possible to
ensure maximum ESD protection.
_______________________________________________________________________________________
5
