MAX3229EEBV MAXIM [Maxim Integrated Products], MAX3229EEBV Datasheet - Page 9

• Manufacturer Part Number: MAX3229EEBV
• Manufacturer: MAXIM [Maxim Integrated Products]

Table 3. Output Control Truth Table
X = Don’t care.
† = I NVALID output state is determined by R_IN input levels.
MAX3228E/MAX3229E feature a separate logic supply
input (V
outputs. The transmitter inputs (T_IN), FORCEON and
FORCEOFF, are also referred to V
maximum flexibility in interfacing to different systems
and logic levels. Connect V
ply voltage (+1.65V to +5.5V), and bypass it with a
0.1µF capacitor to GND. If the logic supply is the same
as V
enabling the V
equal to the V
If direct software control is desired, connect FORCE-
OFF and FORCEON together to disable AutoShutdown.
The microcontroller then drives FORCEOFF and
FORCEON like a SHDN input, INVALID can be used to
alert the microcontroller to indicate serial data activity.
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 driver outputs and receiver inputs of the
MAX3228E/MAX3229E have extra protection against
static electricity. Maxim’s engineers have developed
state-of-the-art structures to protect these pins against
ESD of ±15kV without damage. The ESD structures with-
stand high ESD in all states: normal operation, shut-
down, and powered down. After an ESD event Maxim’s
E versions keep working without latchup, whereas com-
peting RS-232 products can latch and must be powered
down to remove latchup.
ESD protection can be tested in various ways; the trans-
mitter outputs and receiver inputs of this product family
are characterized for protection to the following limits:
1) ±15kV using the Human Body Model.
3) ±15kV using the IEC 1000-4-2 Air-Gap method.
2) ±8kV using the Contact Discharge method specified
Shutdown (AutoShutdown)
Shutdown (Forced Off)
Normal Operation (Forced On)
Normal Operation (AutoShutdown)
in IEC 1000-4-2.
CC
TRANSCEIVER STATUS
, connect V
L
) that sets V
L
L
supply.
Software-Controlled Shutdown
supply. V
_______________________________________________________________________________________
L
to V
OH
CC
for the receiver and INVALID
CC
±15kV ESD-Protected +2.5V to +5.5V
±15kV ESD Protection
. Always enable V
L
to the system’s logic sup-
must be greater than or
L
. This feature allows
FORCEON
High
Low
Low
X
RS-232 Transceivers in UCSP
CC
before
FORCEOFF
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents
test setup, test methodology, and test results.
Figure 5a shows the Human Body Model, and Figure 5b
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 interest,
which is then discharged into the test device through a
1.5kΩ resistor.
Figure 5a. Human Body ESD Test Models
Figure 5b. Human Body Model Current Waveform
AMPERES
High
High
High
Low
VOLTAGE
SOURCE
HIGH-
DC
I
P
36.8%
100%
90%
10%
0
CHARGE-CURRENT
LIMIT RESISTOR
0
R
t
RL
C
RECEIVER STATUS
1MΩ
100pF
C s
High-Z
High-Z
Active
Active
CURRENT WAVEFORM
STORAGE
CAPACITOR
TIME
R
RESISTANCE
D
DISCHARGE
1500Ω
t
DL
I r
ESD Test Conditions
Human Body Model
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
INVALID
H
L
†
†
DEVICE
UNDER
TEST
9