PRELIMINARY
CM2400-02/03/04
Functional Description
The CM2400-02/03/04 USB Transceiver supports 3 dif-
ferent power supply configurations, which can be con-
figured dynamically. Table 1 details the various
configurations. In Normal Mode the internal regulator
D- lines while in sharing mode. In this mode, V and
P
V
are driven high while RCV and USB_DET are
M
driven low.
In Disable and Sharing Mode, all input/output pins fol-
low the states defined in Table 2.
produces 3.3V from V
to power the internal drivers
BUS
and receivers associated with the USB protocol.
Sharing Mode
State
Disable Mode
State
VBUS
VCC
CONFIGURATION
Normal Mode
PIN
Connected
Connected
Connected
Not Connected
Connected
VBUS
VREG
VCC
VBUS < 3.6V
Pulled Down
Present
4.1V to 5.5V
3.3V Out
Disable Mode
Sharing Mode
Not Connected
Not Present
High-Z (off)
Table 1: Power Supply Connections
VPU
High-Z (off)
There are three power supply configurations for the
CM2400-02/03/04: Normal mode, Disable mode and
Sharing mode. These three modes can be changed
dynamically.
D+, D-
High-Z
H
High-Z
Invalid
VP , VM
RCV
USB_DET
Inputs
L
L
Invalid
Invalid
High-Z
Normal mode occurs when the V
and V
inputs
BUS
CC
are both connected to a source. V
is tied to a 5V
High-Z
BUS
source for 5V operation. The internal regulator of the
CM2400-02/03/04 provides 3.3V output on V . The
Table 2: Pin States in Disable or Sharing Mode
REG
Table 3 lists the functions of the modes associated with
suspend and OE pins. When Suspend is low and OE is
high, signal levels on D+ and D- are determined by
other USB devices and pull-up/down resistors. In Sus-
pend Mode (SPND = HIGH) the differential receiver is
inactive and output RCV is always LOW. Out of sus-
pend signaling is detected via the single-ended receiv-
V
input is connected to an independent source that
CC
can range from 1.65V to 3.6V.
When V is not connected and V
is connected,
BUS
CC
the device is in Disable mode. The D+ and D- pins are
in tri-state and power consumption drops to a suspend
state level.
ers V and V . During suspend and while the output is
still enabled (OE = LOW), D+ and D- lines are driven to
their intended states.
P
M
In Sharing mode, V
is connected while V
is
BUS
CC
below 3.6V. The D+ and D- pins are in tri-state and the
CM2400-02/03/04 allows external signals (≤3.6V) to
share these two lines. The CM2400-02/03/04 is
designed to draw almost zero current from the D+ and
VP/VM
SUSPEND OE
D+ / D-
Driver & Receiver Active
Receiving
RCV
Active
Active
Function
L
L
L
H
L
Active
Active
Normal driving mode. Differential receiver active
Driver Tri-stated. Differential receiver active.
H
Driving
Inactive
RCV=L
Active Driving during ’suspend’. Differential receiver inactive.
H
H
High-Z
Inactive
RCV=L
Active Low-power state.
Table 3: Function Selection.
© 2004 California Micro Devices Corp. All rights reserved.
08/24/04 430 N. McCarthy Blvd., Milpitas, CA 95035-5112
●
Tel: 408.263.3214
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Fax: 408.263.7846
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www.calmicro.com 11
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