CM2400-01 Datasheet, PDF (12/14 Pages) California Micro Devices Corp – Universal Serial Bus Transceiver with Level Translator

CM2400-01
Application Information
The CM2400-01 transceiver is targeted for full-speed
(12Mbits/s) USB peripherals including handheld elec-
tronic devices such as PDAs and cell phones. It pro-
vides the interface between the core I/O signals (within
a range of 1.65V and 3.6V) and the USB data lines (D+
and D-) operating at 3.3V.
This section describes how the USB transceiver inter-
faces to the USB port and to the controller or ASIC on
the other side. A small number of external components
is needed that includes two 33Ω series resistors for ter-
mination, two capacitors for filtering, and a 1.5KΩ pull-
up resistor on the D+ data line to configure full-speed
(12Mbits/second) operation. This pull-up resistor is tied
to the V_PU pin which internally connects to V_REG (3.3V)
when ENUM is set High. An internal switch discon-
nects V_PU from V_REG (V_PU floating or high impedance)
when ENUM is set Low.
CAMD offers the PACUSB-U2 filter, available in both
the SC70 and SOT23 6-lead packages, that integrates
all these components as well as the additional ESD
protection rated to 15kV per the IEC61000-4-2 stan-
dard (exceeding level 4). Figure 10 shows a typical
electrical schematic for a USB peripheral application.
The driver output resistance for the full-speed driver,
should be between 28Ω and 44Ω (refer to the USB
Specification section 7.1.1.1). Since the CM2400-01
output impedance is about 6Ω, it is recommended that
33Ω series resistors be used.
Figure 10. Schematic for USB Peripheral Device
• The MODE pin selects the differential receiver
mode when High (CMOS level or V_CC), and selects
the single-ended receiver mode when Low (con-
nected to GND).
• The CM2400-01 is used in bus-powered systems
only, where the V_BUS supply pin is connected to
the +5V V_BUS line from the USB connector.
• The V_CC supply pin is the supply for the I/O signal
logic that provide the interface with the ASIC. The
V_CC supply must range between 1.65V min and
3.6V max.
© 2003 California Micro Devices Corp. All rights reserved.
12 430 N. McCarthy Blvd., Milpitas, CA 95035-5112 L Tel: [phone]
L Fax: [phone] L www.calmicro.com
10/01/03