MAX20044F datasheet(13/16 Pages) AD

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EN Input

is an active-low enable input. Drive EN low for normal

operation and enable the protection switches. This allows

BUS power, D+, and D- USB signaling to pass through

the device if a fault is not present. Drive EN high to dis-

able the device.

The MAX20042F, MAX20043F, and MAX20044F devices

support USB OTG. With these units, disabling the device

through the EN pin disables the +5V BUS power switch, but

leaves the D+ and D- data switches closed. This allows for a

downstream device to assume the role of host when nego-

tiated per the USB Host Negotiation Protocol. In this mode,

the HVBUS, HVD+, and HVD- outputs continue to be pro-

tected and FAULT continues to assert normally in response

to overvoltage conditions on these pins.

Applications Information

Power-Supply Bypass Capacitor

Bypass HVBUS to GND with a 10µF and a 0.1µF ceramic

capacitor as close to the device as possible to provide

±15kV (HBM) ESD protection on the pin. If the power

source has significant inductance due to long lead length,

take care to prevent overshoots due to the LC tank circuit

and provide protection if necessary to prevent violation

of the +6V absolute maximum rating on BUS. Connect

a 100µF low-ESR ceramic capacitor from BUS to GND.

Connect a 0.1µF and 10µF ceramic capacitor from both

BUS and IN to GND. Place these components on the

same plane as the IC, close to the IN and GND pins.

Layout of USB Data Line Traces

USB Hi-Speed requires careful PCB layout with 90Ω

controlled-impedance matched traces of equal lengths.

Use LC tuning components on the data lines as shown in

the Typical Operating Circuit. The values of these com-

ponents are layout and captive-cable dependent. Contact

Analog Devices technical support for more detailed infor-

mation.

±15kV ESD Protection

As with all Analog Devices ICs, ESD-protection structures

are incorporated on all pins to protect against electrostatic

discharges encountered during handling and assembly.

The devices have extra protection against static electric-

ity. Analog Devices engineers have developed state-of-

the-art structures to protect against ESD of ±15kV at the

HVD+, HVD-, and HVBUS ports without damage. The

ESD structures withstand high ESD in all states: normal

operation, shutdown, and powered down. After an ESD

event, the devices keep working without latchup, whereas

other solutions can latch and must be powered down to

remove latchup. ESD protection can be tested in various

ways; this product is characterized for protection to the

following limits:

● ±15kV using the Human Body Model

● ±15kV using IEC 61000-4-2’s Air-Gap Discharge

method, EN = GND

● ±8kV using the Contact Discharge method specified

in IEC 61000-4-2, EN = GND

ESD Test Conditions

ESD performance depends on a variety of conditions.

Contact Analog Devices for a reliability report that docu-

ments 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 discharged

into a 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.

IEC 61000-4-2

The IEC 61000-4-2 standard covers ESD testing and

performance of finished equipment. The MAX20042F,

MAX20043F, and MAX20044F devices help users design

equipment that meets Level 4 of IEC 61000-4-2. The

main difference between tests done using the Human

Body Model and IEC 61000-4-2 is higher peak current

in IEC 61000-4-2. Because series resistance is lower in

the IEC 61000-4-2 ESD test model (Figure 10), the ESD

withstand voltage measured to this standard is generally

lower than that measured using the Human Body Model.

Figure 11 shows the current waveform for the ±8kV, IEC

61000-4-2 Level 4, ESD Contact Discharge test. The

Air-Gap Discharge test involves approaching the device

with a charged probe. The Contact Discharge method

connects the probe to the device before the probe is

energized.

www.analog.com

Analog Devices │ 13

MAX20042F–MAX20044F

Automotive Hi-Speed USB 2.0 Protectors

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