MAX1488E Datasheet, PDF (4/8 Pages) Maxim Integrated Products – ±15kV ESD-Protected, Quad, Low-Power RS-232 Line Driver

±15kV ESD-Protected, Quad, Low-Power
RS-232 Line Driver
_____________________Pin Description
PIN
NAME
FUNCTION
1
VEE -4.5V to -13.2V Supply Voltage Input
2, 4, 5, 9,
10, 12, 13
INPUT_ Driver Inputs
3, 6, 8, 11 OUTPUT_ Driver Outputs
7
GND Ground
14
VCC +4.5V to +13.2V Supply Voltage Input
_______________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.
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.
Table 1. Driver A Functions
INPUT A
H
L
OUTPUTA
L
H
Table 2. Driver B–D Functions
INPUT_1
H
L
X
INPUT_2
H
X
L
OUTPUT_
L
H
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.
±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
3.0V
DRIVER
INPUT
1.5V
0V
TPHL
TPLH
VOH
3.3V
3.0V
VOUT
0V
-3.0V
-3.3V
tF2
tR2
VOL
tF1
tR1
SIGNAL
GENERATOR
RL
CL
Figure 1. Slew-Rate Test Circuit and Timing Diagram
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).
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.
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