CM2400-01 Datasheet, PDF (10/14 Pages) California Micro Devices Corp – Universal Serial Bus Transceiver with Level Translator

CM2400-01
Functional Description
The CM2400-01HB USB Transceiver supports 3 differ-
ent power supply configurations, which can be config-
ured dynamically. Table 1 details the various
configurations. In Normal Mode the internal regulator
produces 3.3V from V_BUS to power the internal drivers
and receivers associated with the USB protocol.
V_BUS
Connected
Connected
Not Connected
V_CC
Connected
Not Connected
Connected
CONFIGURATION
Normal Mode
Disable Mode
Sharing Mode
Table 1: Power Supply Connections
There are three power supply configurations for the
CM2400-01HB: Normal mode, Disable mode and
Sharing mode. These three modes can be changed
dynamically.
Normal mode occurs when the V_CC and V_BUS inputs
are both connected to a source. V_BUS is tied to a 5V
source for 5V operation. The internal regulator of the
CM2400-01HB provides 3.3V output on V_REG. The
V_CC input is connected to an independent source that
can range from 1.65V to 3.3V.
When V_CC is not connected and V_BUS is connected,
the device is in Disable mode. The D+ and D- pins are
in tri-state and power consumption drops to a suspend
state level.
In Sharing mode, V_CC is connected while V_BUS is
below 3.6V. The D+ and D- pins are in tri-state and the
CM2400 allows external signals (<3.6V) to share these
two lines. The CM2400-01HB is designed to draw
almost zero current from the D+ and D- lines while in
sharing mode. In this mode, V_P and V_M are driven high
while RCV and USB_DET are driven low.
In Disable and Sharing Mode, all input/output pins fol-
low the states defined in Table 2.
PIN
V_BUS
V_REG
V_CC
V_PU
D+, D-
V_P, V_M
RCV
USB_DET
Inputs
Sharing Mode
State
V_BUS < 3.6V
Pulled Down
Present
High-Z (off)
High-Z
H
L
L
High-Z
Disable Mode
State
4.1V to 5.5V
3.3V Out
Not Present
High-Z (off)
High-Z
Invalid
Invalid
Invalid
High-Z
Table 2: Pin States in Disable or Sharing Mode
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-
ers V_P and V_M. During suspend and while the output is
still enabled (OE = LOW), D+ and D- lines are driven to
their intended states.
SUSPEND OE
L
L
L
H
H
L
H
H
D+ / D-
RCV
V_P/V_M
Function
Driver & Receiver Active Active Active
Normal driving mode. Differential receiver active
Receiving
Active Active
Driver Tri-stated. Differential receiver active.
Driving
Inactive Active Driving during ’suspend’. Differential receiver inactive.
RCV=L
High-Z
Inactive Active
RCV=L
Low-power state.
Table 3: Function Selection.
© 2003 California Micro Devices Corp. All rights reserved.
10 430 N. McCarthy Blvd., Milpitas, CA 95035-5112 L Tel: [phone]
L Fax: [phone] L www.calmicro.com
10/01/03