USB1T1102 View Datasheet(PDF) - Fairchild Semiconductor
Part Name
Description
Manufacturer
USB1T1102 Datasheet PDF : 14 Pages
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Power Supply Configurations and Options
The two modes of power supply operation are:
• Normal Mode: VCCIO and VCC (5V) are connected or
VCCIO, VCC (5V) and [VREG (3.3V) and VCC (5V) shorted
for Bypass mode]
1. For 5V operation VCC is connected to 5V source
(4.0V to 5.5V) and the internal voltage regulator then
produces 3.3V for the USB connections.
2. For 3.3V operation both VCC and VREG are con-
nected to a 3.3V source (3.0V to 3.6V)
In both cases for normal mode the VCCIO is an indepen-
dent voltage source (1.65V to 3.6V) that is a function of
the external circuit configuration.
• Sharing Mode: VCCIO is only supply connected. VCC and
VREG are not connected. In this mode the D+ and D−
pins are 3-STATE and the USB1T1102 allows external
signals up to 3.6V to share the D+ and D− bus lines.
Internally the circuitry limits leakage from D+ and D−
pins (maximum 10 µA) and VCCIO such that device is in
low power (suspended) state. Pins Vbusmon and RCV
are forced LOW as an indication of this mode with Vbus-
mon being ignored during this state.
A summary of the Supply Configurations is described in
Table 4.
Pins
VCC (5V)
VREG (3.3V)
VCCIO
VPU (3.3V)
D+, D−
Vp/Vpo, Vm/Vmo
RCV
Vbusmon
OE, SUSPND, Config
TABLE 4. Power Supply Configuration Options
Sharing
Not Connected
Not Connected
1.65V to 3.6V Source
3-STATE (Off)
3-STATE
L
L
L
Hi-Z
Power Supply Mode Configuration
Normal (Regulated Output) Normal (Regulator Bypass)
Connected to 5V Source
Connected to VREG (3.3V)
[Max Drop of 0.3V]
(2.7V to 3.6V)
3.3V, 300 µA
Regulated Output
Connected to 3.3V Source
1.65V to 3.6V Source
1.65V to 3.6V Source
3.3V Available if
Config = HIGH
3.3V Available if
Config = HIGH
Function of Mode Set Up
Function of Mode Set Up
Function of Mode Set Up
Function of Mode Set Up
Function of Mode Set Up
Function of Mode Set Up
Function of Mode Set Up
Function of Mode Set Up
Function of Mode Set Up
Function of Mode Set Up
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