MAX3345E Просмотр технического описания (PDF) - Maxim Integrated

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MAX3345E

±15kV ESD-Protected USB Transceivers in UCSP with USB Detect

Maxim Integrated 

±15kV ESD-Protected USB Transceivers

in UCSP with USB Detect

VL

OE

VL/2

0V

tPZD

tPDZ

D+/D-

VOHD - 0.3V

VOLD + 0.3V

Figure 2. Enable and Disable Timing, Transmitter

VL

VPO

0V

VTRM

VL/2

tPHLO

tPLHO

D+

0V

D-

Figure 3. Mode 0 Timing

VL

0V

VL

VL/2

0V

VTRM

VL/2

tPHL1

VL/2

tPLH1

VPO

tPLH1

VMO

tPLH1

D+

0V

D-

Figure 4. Mode 1 Timing

Data Transfer

Receiving Data from the USB

Data received from the USB are output to VPI/VMI in

either of two ways, differentially or single ended. To

receive data from the USB, force OE high and SUSP low.

Differential data arriving at D+/D- appear as differential

logic signals at VPI/VMI, and as a single-ended logic sig-

nal at RCV. If both D+ and D- are low, then VPI and VMI

are low, signaling a single-ended zero condition on the

bus; RCV remains in the last known state (Table 3).

Transmitting Data to the USB

The MAX3344E/MAX3345E output data to the USB dif-

ferentially on D+ and D-. The logic driving signals can

be either differential or single ended. For sending differ-

ential logic, force MODE high, force OE and SUSP low,

and apply data to VPO and VMO. D+ then follows VPO,

and D- follows VMO. To send single-ended logic sig-

nals, force MODE, SUSP, and OE low, and apply data to

VPO/VMO.

ESD Protection

To protect the MAX3344E/MAX3345E against ESD, D+

and D- have extra protection against static electricity to

protect the device up to ±15kV. The ESD structures

withstand high ESD in all states—normal operation,

suspend, and powered down. For the 15kV ESD struc-

tures to work correctly, a 1µF or greater capacitor must

be connected from VTRM to GND.

ESD protection can be tested in various ways; the D+

and D- input/output pins are characterized for protection

to the following limits:

1) ±15kV using the Human Body Model

2) ±8kV using the IEC 1000-4-2 Contact Discharge

Method

3) ±10kV using the IEC 1000-4-2 Air-Gap Method

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 1a shows the Human Body Model, and Figure 1b

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.

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