±15kV ESD-Protected USB Transceivers with

External/Internal Pullup Resistors

10

______________________________________________________________________________________

the internal portions of the USB circuitry and provides

the pullup voltage for the MAX13481E/MAX13482E.

vide power to any other external circuitry.

D+ and D-

D+ and D- serve as bidirectional bus connections and

are ESD-protected to ±15kV (Human Body Model). For

OE = low, D+ and D- serve as transmitter outputs. For

OE = high, D+ and D- serve as receiver inputs.

BD (MAX13482E/MAX13483E)

MAX13482E/MAX13483E enter sharing mode (Table 2).

minal on the USB connector (see the Power-Supply

itor as close to the device as possible.

External Components

External Capacitors

The MAX13481E/MAX13482E/MAX13483E require

three external capacitors for proper operation. Bypass

Install all capacitors as close to the device as possible.

External Resistor

Proper USB operation requires two external resistors,

each 27

Ω ±1%. Install one resistor in series between D+

of the MAX13481E/MAX13482E/MAX13483E and D+ on

the USB connector. Install the other resistor in series

between D- of the MAX13481E/MAX13482E/MAX13483E

and D- on the USB connector (see the Typical Operating

Circuits). The MAX13483E requires an external 1.5k

Ω

operation. The MAX13481E requires an external 1.5k

Ω

pullup resistor between VPU and D+ for full-speed oper-

ation. The MAX13482E does not require an external

pullup resistor but VPUR must be connected to D+ for

full-speed operation.

Data Transfer

Transmitting Data to the USB

To transmit data to the USB, drive

OE low. The

MAX13481E/MAX13482E/MAX13483E transmit data to

the USB differentially on D+ and D-. VP and VM serve

as input signals to the differential driver and are also

used to assert a single-ended zero (SE0) driver (see

Table 3).

Receiving Data from the USB

To receive data from the USB, drive

OE high and SUS

low. Differential data received by D+ and D- appears at

RCV. Single-ended receivers on D+ and D- drive VP

and VM, respectively.

RCV

RCV monitors D+ and D- when receiving data. RCV is a

logic 1 for D+ high and D- low. RCV is a logic 0 for D+

low and D- high. RCV retains its last valid state when

D+ and D- are both low (single-ended zero, or SE0).

ESD Protection

D+ and D- possess extra protection against static elec-

tricity to protect the devices up to

±15kV. The ESD

structures withstand high ESD in all operating modes:

normal operation, suspend mode, and powered down.

D+ and D- provide protection to the following limits:

•±15kV using the Human Body Model

•±8kV using the Contact Discharge method specified

in IEC 61000-4-2

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 6 shows the Human Body Model and Figure 7

shows the current waveform generated when dis-

charged into a low impedance. This model consists of

a 100pF capacitor charged to the ESD voltage of inter-

est, which then discharges into the test device through

a 1.5k

Ω resistor.

IEC 61000-4-2

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

performance of finished equipment. It does not specifi-

cally refer to integrated circuits. The major difference

between tests done using the Human Body Model and

IEC 61000-4-2 is a higher peak current in IEC 61000-4-

2, due to lower series resistance. Hence, the ESD with-