
MAX3346E
±15kV ESD-Protected USB Transceiver
in UCSP
8
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Applications Information
Power-Supply Configurations
Normal Operating Mode
Connect VL and VCC to system power supplies (Table
1). Connect VL to a +1.65V to +3.6V supply. Connect
VCC to a +4.0V to +5.5V supply. Alternatively, the
MAX3346E can derive power from a single Li+ battery.
Connect the battery to VCC. VTRM remains above
+3.0V for VCC as low as +3.1V.
Additionally, the MAX3346E can derive power from a
3.3V ±10% voltage regulator. Connect VCC and VTRM
to an external +3.3V voltage regulator.
Disable Mode
Connect VCC to a system power supply and leave VL
unconnected or connect to GND. D+ and D- enter a tri-
state mode and VCC consumes less than 20A of sup-
ply current. D+ and D- withstand external signals up to
+5.5V in disable mode (Table 2).
Sharing Mode
Connect VL to a system power supply and leave VCC
(or VCC and VVTRM) unconnected or connect to GND.
D+ and D- enter a tri-state mode, allowing other circuit-
ry to share the USB D+ and D- lines, and VL consumes
less than 20A of supply current. D+ and D- withstand
external signals up to +5.5V in sharing mode (Table 2).
Device Control
OE
OE controls the direction of communication through the
device. With OE low, the MAX3346E transfers data from the
system side to the USB side. With OE high, the MAX3346E
transfers data from the USB side to the system side.
ENUM
The MAX3346E allows software control of USB enumera-
tion. USB specification 1.1 requires a 1.5k pullup resistor
to D+ or D- to set the transmission speed (see the SPEED
section). Enumerating the USB requires removing the 1.5k
resistor from the circuit, and is accomplished with the
MAX3346E by driving ENUM low. With ENUM high, the volt-
age at SPEED determines how the internal resistor is con-
nected (see the Functional Diagram).
MODE
MODE is a control input that selects whether differential
or single-ended logic signals are recognized by the
system side of the MAX3346E (Table 3).
If MODE is forced high, differential input is selected. With
differential input selected, outputs D+ and D- follow the
differential inputs at VP and VM. If VP and VM are both
forced low, an SE0 condition is forced on the USB.
Drive MODE and VM low for single-ended input mode.
With single-ended input selected, the differential sig-
nal on D+ and D- is controlled by VP. If VM is high
when MODE is low, D- and D+ are both low, forcing
an SE0 condition.
VCC (V)
VTRM (V)
VL (V)
CONFIGURATION
NOTES
+4.0 to +5.5
+3.3 Output
+1.65 to +3.6
Normal mode
—
+3.1 to +4.5
+3.3 Output
+1.65 to +3.6
Battery supply
—
+3.0 to +3.6
+3.0 to +3.6 Input
+1.65 to +3.6
Voltage regulator supply
—
GND or floating
Output
+1.65 to +3.6
Sharing mode
Table 2
+3.0 to +5.5
Output
GND or floating
Disable mode
Table 2
Table 1. Power-Supply Configurations
INPUTS/OUTPUTS
DISABLE MODE
SHARING MODE
VCC/VTRM
+5V input/+3.3V output
+3.3V input/+3.3V output
+3.7V input/+3.3V output
Floating or connected to GND
VL
Floating or connected to GND
+1.65V to +3.6V input
D+ and D-
High impedance
SPEED, SUSP, OE, ENUM
High impedance
Table 2. Disable-Mode and Sharing-Mode Configurations