±15kV ESD

protection protects the D+ and D- USB I/O ports.

The MAX3451E features an enumerate function provid-

ing an internal 1.5k

merate function disconnects the 1.5k

Ω pullup resistor,

allowing the MAX3451E to simulate a bus disconnect

while powered and connected to the USB cable. The

MAX3450E is pin-for-pin compatible with Micrel’s

MIC2550A. The MAX3452E features a BD output that

MAX3452E require external pullup resistors from either

Applications Information

Power-Supply Configurations

Normal Operating Mode

the MAX3450E and MAX3451E can derive power from

Additionally, the MAX3450E and MAX3451E can derive

power from a +3.3V

±10% voltage regulator. Connect

linear regulator in this configuration.

Disable Mode

unconnected or connect to GND. D+ and D- enter a tri-

less than 20µA of supply current. D+ and D- withstand

external signals up to +5.5V in disable mode (Table 2).

Sharing Mode

D+ and D- enter a tri-state mode, allowing other circuitry

than 20µA of supply current. D+ and D- withstand

external signals up to +5.5V in sharing mode (Table 2).

±15kV ESD-Protected USB Transceivers

8

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Table 1. Power-Supply Configurations

CONFIGURATION

NOTES

+4.0 to +5.5

+3.0 to +3.6 output

+1.65 to +3.6

Normal mode

—

+3.1 to +4.5

+3.0 to +3.6 output

+1.65 to +3.6

Battery supply

MAX3450E, MAX3451E

+3.0 to +3.6

+3.0 to +3.6 input

+1.65 to +3.6

Voltage regulator supply

MAX3450E, MAX3451E

GND or floating

Output

+1.65 to +3.6

Sharing mode

Table 2

+3.0 to +5.5

GND or floating

Disable mode

Table 2

*High impedance or low

**High or low

INPUTS/OUTPUTS

DISABLE MODE

SHARING MODE

• +5V input/+3.3V output

• +3.3V input/+3.3V input (MAX3450E and MAX3451E)

• +3.7V input/+3.3V output (MAX3450E and MAX3451E)

• Floating or connected to GND (MAX3450E

and MAX3451)

• < +3.6V (MAX3452E)

Floating or connected to GND

+1.65V to +3.6V input

D+ and D-

High impedance

High impedance

High impedance for

OE = low

VP and VM

Invalid*

High for

OE = high

RCV

Invalid*

Undefined**

SPD, SUS,

OE, ENUM

(MAX3451E)

High impedance

High impedance

BD (MAX3452E)

Invalid*

Low

Table 2. Disable-Mode and Sharing-Mode Connections