MAX3355E
OFFVBUS
Connect OFFVBUS to GND to disable VBUS and the
charge pump (Table 4). For normal VBUS operation,
connect OFFVBUS to VL. When OFFVBUS = GND, VBUS
impedance is between 40kΩto 100kΩas defined in On-
the-Go Supplement: USB 2.0, Revision 1.0.
SHDN
The MAX3355E shutdown mode reduces supply current
to less than 1µA. To enter shutdown mode, connect
SHDN to GND. Shutdown mode disables the charge
pump and comparators (Table 4). While in shutdown
mode, the STATUS1 output defaults to logic 0 and STA-
TUS2 indicates VBUS. During shutdown, if VBUS is exter-
nally driven above VTH,SHDN (defined in the Comparators
section), the MAX3355E sinks current from VCC.
Applications Information
±15kV ESD Protection
To protect the MAX3355E against ESD, ID_IN and VBUS
have extra protection against static electricity to protect
the device up to ±15kV. For ±15kV protection on VBUS,
a 1µF capacitor must be connected from VBUS to GND
as close to the device as possible. The ESD structures
withstand high ESD in all states—normal operation,
shutdown, and powered down. ESD protection can be
tested in various ways. The ID_IN input and VBUS 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) ±15kV using the IEC 1000-4-2 Air-Gap Discharge
method
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 1 shows the Human Body Model and Figure 2
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
1.5kΩresistor.
IEC 1000-4-2
The IEC 1000-4-2 standard covers ESD testing and
performance of finished equipment. It does not specifi-
cally refer to integrated circuits. The MAX3355E helps
the user design equipment that meets Level 4 of IEC
1000-4-2, without the need for additional ESD-protec-
tion components. The major difference between tests
done using the Human Body Model and IEC 1000-4-2
is a higher peak current in IEC 1000-4-2. This occurs
because series resistance is lower in the IEC 1000-4-2
model. Hence, the ESD withstand voltage measured to
±15kV ESD-Protected USB On-the-Go
Charge Pump and Comparators in UCSP
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