sp385e-1 Exar Corporation, sp385e-1 Datasheet - Page 7

• Manufacturer Part Number: sp385e-1
• Description: 232 Line Driver/receiver
• Manufacturer: Exar Corporation

Figure 4. Charge Pump — Phase 3
Figure 5. Charge Pump — Phase 4
Shutdown (ON/OFF)
The SP385E-1 has a shut-down/standby mode
to conserve power in battery-powered
systems. To activate the shutdown mode,
which stops the operation of the charge pump,
a logic "0" is applied to the appropriate
control line. The shutdown mode is controlled
on the SP385E-1 by a logic "0" on the ON/
OFF control line (pin 18 for the SOIC and pin
20 for the SSOP packages); this puts the
transmitter outputs in a tri-state mode.
ESD Tolerance
The SP385E-1 device incorporates rugge-
dized ESD cells on all driver output and
receiver input pins. The ESD structure is
improved over our previous family for more
rugged applications and environments
sensitive to electro-static
discharges and associated transients. The
improved ESD tolerance is at least ±15KV
without damage nor latch-up.
There are different methods of ESD testing
applied:
The Human Body Model has been the
generally accepted ESD testing method for
semiconductors. This method is also specified
Rev. 07/26/02
C
C
a) MIL-STD-883, Method 3015.7
b) IEC1000-4-2 Air-Discharge
c) IEC1000-4-2 Direct Contact
1
1
–5V
+
–
+
–
V
V
CC
CC
= +5V
= +5V
C
C
2
2
+10V
+
+5V
–5V
–
+
–
+
–
+
C
–
C
C
C
4
4
+
3
3
–
+
–
V
V
V
V
DD
SS
SP385E-1 True +3V to +5V RS-232 Line Driver/Receiver
DD
SS
Storage Capacitor
Storage Capacitor
Storage Capacitor
Storage Capacitor
7
in MIL-STD-883, Method 3015.7 for ESD
testing. The premise of this ESD test is to
simulate the human body’s potential to store
electro-static energy and discharge it to an
integrated circuit. The simulation is
performed by using a test model as shown in
Figure 6. This method will test the IC’s
capability to withstand an ESD transient
during normal handling such as in
manufacturing areas where the ICs tend to be
handled frequently.
The IEC-1000-4-2, formerly IEC801-2, is
generally used for testing ESD on equipment
and systems. For system manufacturers, they
must guarantee a certain amount of ESD
protection since the system itself is exposed to
the outside environment and human presence.
The premise with IEC1000-4-2 is that the
system is required to withstand an amount of
static electricity when ESD is applied to points
and surfaces of the equipment that are
accessible to personnel during normal usage.
The transceiver IC receives most of the ESD
current when the ESD source is applied to the
connector pins. The test circuit for IEC1000-
4-2 is shown on Figure 7. There are two
methods within IEC1000-4-2, the Air
Discharge method and the Contact Discharge
method.
Figure 6. ESD Test Circuit for Human Body Model
Figure 7. ESD Test Circuit for IEC1000-4-2
DC Power
Source
DC Power
Source
R
R
C
C
R
R
C
C
SW1
SW1
SW1
SW1
C
C
© Copyright 2001 Sipex Corporation
S
S
C
C
S
R S and R V add up to 330 for IEC1000-4-2.
R S and R V add up to 330 for IEC1000-4-2.
S
R
R
S
S
R
R
S
S
Contact-Discharge Module
Contact-Discharge Module
R
R
V
V
SW2
SW2
SW2
SW2
Device
Under
Test
Device
Under
Test