USBIT1103 Datasheet, PDF (5/16 Pages) Fairchild Semiconductor – Universal Serial Bus Peripheral Transceiver with Voltage Regulator

Power Supply Configurations and Options
The three modes of power supply operation are:
Normal Mode: Regulated Output and Regulator Bypass
1. Regulated Output: V_CCIO is connected and V_CC(5.0)
is connected to 5V (4.0V to 5.5V) and the internal
voltage regulator then produces 3.3V for the USB
connections.
2. Internal Regulator Bypass Mode: V_CCIO is con-
nected and both V_CC(5.0) and V_REG(3.3) are con-
nected to a 3.3V source (3.0V to 3.6V).
In both cases, for normal mode, the V_CCIO is an indepen-
dent voltage source (1.65V to 3.6V) that is a function of
the external circuit configuration.
Sharing Mode: V_CCIO is only supply connected. V_CC
and V_REG are not connected. In this mode, the D+ and
D- terminals are 3-STATE and the USB1T1103 allows
external signals up to 3.6V to share the D+ and D- bus
lines. Internally the circuitry limits leakage from D+ and
D- terminals (maximum 10µA) and V_CCIO such that
device is in low power (suspended) state. Terminals
Vbusmon and RCV are forced LOW as an indication of
this mode with Vbusmon being ignored during this state.
Disable Mode: V_CCIO is not connected. V_CC is con-
nected, or V_CC and V_REG are connected. 0V to 3.3V in
this mode D+ and D- are 3-STATE and V_PU is HIGH
Impedance (switch is turned off). The USB1T1103 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 10µ A).
A summary of the Supply Configurations is described in
Table 4.
Table 4. Power Supply Configuration Options
Terminals
V_CC (5V)
Disable
Connected
to 5V source
Sharing
Not Connected
or <3.6V
V_REG (3.3V)
V_CCIO
V_PU (3.3V)
D =, D-
3.3V, 300µA
Regulated Output
≤0.5V
3-STATE (off)
Not Connected
1.65V to 3.6V Source
3-STATE (off)
3-STATE (off)
3-STATE
V_p/V_po, V_m/V_mo
Invalid [I]
L
RCV
Invalid [I]
L
Vbusmon
Invalid [I]
L
OE, SUSPND, Config
Hi-Z
Hi-Z
Notes:
6. Invalid [I] I/O are to be 3-STATE, outputs to be LOW.
Normal
(Regulated Output)
Connected to
5V Source
3.3V, 300µA
Regulated Output
1.65V to 3.6V Source
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
Normal
(Regulator Bypass)
Connected to
V_REG (3.3V)
[Max Drop of 0.3V]
(2.7V to 3.6V)
Connected to 3.3V Source
1.65V to 3.6V Source
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
© 2005 Fairchild Semiconductor Corporation
USB1T1103 Rev. 1.0.3
5
www.fairchildsemi.com