Detailed Description

The MAX3030E–MAX3033E are high-speed quad RS-

422 transmitters designed for digital data transmission

over balanced lines. They are designed to meet the

requirements of TIA/EIA-422-B and ITU-T V.11. The

MAX3030E–MAX3033E are available in two pinouts to

be compatible with both the 26LS31 and SN75174

industry-standard devices. Both are offered in 20Mbps

and 2Mbps baud rate. All versions feature a low-static

ideal for battery-powered and power-conscious appli-

cations. The 20Mbps version has a maximum propaga-

tion delay of 16ns and a part-to-part skew less than

5ns, allowing these devices to drive parallel data. The

2Mbps version is slew-rate-limited to reduce EMI and

reduce reflections caused by improperly terminated

cables.

Outputs have enhanced ESD protection providing

±15kV tolerance. All parts feature hot-swap capability

that eliminates false transitions on the data cable dur-

ing power-up or hot insertion.

±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 driver outputs and receiver inputs have

extra protection against static electricity. Maxim’s engi-

neers developed state-of-the-art structures to protect

these pins against ESD of ±15kV without damage. The

ESD structures withstand high ESD in all states: normal

operation and power-down. After an ESD event, the

MAX3030E–MAX3033E keep working without latchup.

ESD protection can be tested in various ways; the

transmitter outputs of this product family are character-

ized for protection to ±15kV using the Human Body

Model. Other ESD test methodologies include

IEC10004-2 Contact Discharge and IEC1000-4-2 Air-

Gap Discharge (formerly IEC801-2).

ESD Test Conditions

ESD performance depends on a variety of conditions.

Contact Maxim for a reliability report that documents

test setup, test methodology, and test results.

Human Body Model

Figure 8 shows the Human Body Model, and Figure 9

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 test device through a

1.5k

Ω resistor.

±15kV ESD-Protected, 3.3V Quad

RS-422 Transmitters

8

_______________________________________________________________________________________

DI

GND

A

A

DO_-

DO_+

Figure 7. Power-Off Measurements

Test Circuits and

Timing Diagrams (continued)

CHARGE-CURRENT-

LIMIT RESISTOR

DISCHARGE

RESISTANCE

STORAGE

CAPACITOR

Cs

100pF

1M

Ω

1.5k

Ω

HIGH-

VOLTAGE

DC

SOURCE

DEVICE

UNDER

TEST

Figure 8. Human Body ESD Test Model

90%

36.8%

TIME

CURRENT WAVEFORM

PEAK-TO-PEAK RINGING

(NOT DRAWN TO SCALE)

Ir

10%

0

0

AMPS

Figure 9. Human Body Current Waveform