Datasheet

MAX3040–MAX3045
±10kV ESD-Protected, Quad 5V RS-485/RS-422
Transmitters
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Detailed Description
The MAX3040–MAX3045 are quad RS-485/RS-422 trans-
mitters. They operate from a single +5V power supply
and are designed to give optimum performance when
used with the MAX3093E/MAX3095 5V quad RS-485/
RS-422 receivers or MAX3094E/MAX3096 3V quad
RS-485/RS-422 receivers. The MAX3040–MAX3045 only
need 1mA of operating supply current and consume 2nA
when they enter a low-power shutdown mode. The
MAX3040–MAX3045 also feature a hot-swap capability
allowing line insertion without erroneous data transfer.
The MAX3042B/MAX3045B are capable of transferring
data up to 20Mbps, the MAX3041/MAX3044 for data
rates up to 2.5Mbps, and the MAX3040/MAX3043 for
data rates up to 250kbps. All transmitter outputs are pro-
tected to ±10kV using the Human Body Model.
±10kV ESD Protection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electro-
static discharges (ESD) encountered during handling
and assembly. The MAX3040–MAX3045 transmitter
outputs have extra protection against electrostatic dis-
charges found in normal operation. Maxim’s engineers
have developed state-of-the-art structures to protect
these pins against the application of ±10kV ESD
(Human Body Model), without damage.
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 6a shows the Human Body Model, and Figure
6b shows the current waveform it generates when dis-
charged into low impedance. This model consists of a
100pF capacitor charged to the ESD voltage of interest,
which is then discharged into the device through a
1.5kΩ resistor.
R
R
V
OD
V
OC
Y
Z
Figure 1. Driver DC Test Circuit
DI
DE
5V
Y
Z
C
DIFF
V
OD
R
DIFF
Figure 2. Driver Timing Test Circuit
DI
3V
0
Z
Y
V
O
0
-V
O
V
O
1.5V
t
PLH
1/2 V
O
10%
t
R
90%
90%
t
PHL
1.5V
1/2 V
O
10%
t
F
V
DIFF
= V (Y) - V (Z)
V
DIFF
t
SKEW = |
t
PLH
- t
PHL |
Figure 3. Driver Propagation Delays
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
3V
0
Y, Z
V
OL
Y, Z
0
1.5V 1.5V
V
OL
+0.5V
V
OH
-0.5V
2.5V
2.5V
t
ZL(SHDN)
, t
ZL
t
LZ
t
ZH(SHDN)
, t
ZH
t
HZ
DE
Figure 5. Driver Enable and Disable Times
OUTPUT
UNDER TEST
S1
S2
V
CC
C
L
R
L
Figure 4. Driver Enable/Disable Timing Test Load