Si2439-A-FM18-EVB Silicon Labs, Si2439-A-FM18-EVB Datasheet - Page 9

• Manufacturer Part Number: Si2439-A-FM18-EVB
• Description: Networking Development Tools 38pin Si2439+ Si3018 ISOmodem Eval Board
• Manufacturer: Silicon Labs
• Type: Network Controller & Processorr

Specifications of Si2439-A-FM18-EVB

• Rohs: yes
• Tool Is For Evaluation Of: Si2439
• Data Rate: 56 Kbps
• Interface Type: RJ-11, RS-232, SPI, UART, USB
• Operating Supply Voltage: 3.3 V

card and the RJ-11 phone jack.
2.1.1. Voltage Regulator/Power Supply
The input voltage to either J8 or J9 must be between 7.5
and 13.5 V dc or 7.5 and 13.5 V
motherboard includes a diode bridge (D12) to guard
against a polarity reversal of the dc voltage or to rectify
an ac voltage. The power source must be capable of
continuously supplying at least 100 mA. C44 serves as
a filter cap for an ac input. The voltage regulator, U10,
provides 5 V for the motherboard and the input for
voltage regulator U3, which outputs 3.3 V for use on the
motherboard and to power the daughter card. Si24xxDC
power consumption can be measured by placing a
meter across R59. Power is supplied to U2 through D5
from the USB.
2.1.2. Reset Circuitry
The Si2493/57/34/15/04 requires a reset pulse to
remain low for at least 5.0 ms after the power supply
has stabilized during the powerup sequence or for at
least 5.0 ms during a power-on reset. Most production
Si2493/57/34/15/04 modem chipset applications require
that RESET be controlled by the host processor. Certain
Si2493/57/34/15/04
powerdown, require a hardware reset to recover.
The
options, an automatic power-on reset device, U18
(DS1818) (default), and a manual reset switch (S1) to
permit resetting the chip without removing power. A
reset, regardless of the mechanism, causes all modem
settings to revert to factory default values.
2.1.3. Automatic Reset (DS1818)
The DS1818 is a small, low-cost device that monitors
the voltage on V
V
active-low reset pulse. On powerup, the DS1818 also
outputs an active low reset pulse for 220 ms after V
reaches 90% of the nominal 3.3 V value. The DS1818
outputs a 220 ms reset pulse any time the power supply
voltage exceeds the 3.3 V ±10% window.
2.1.4. Manual Reset
The manual reset switch (S1) performs a power-on
reset. This resets the Si2493/57/34/15/04 to factory
defaults without turning off power. Pressing S1 activates
the reset monitor in the DS1818 and produces a 220 ms
active low reset pulse.
D
drops below 3.0 V, the DS1818 provides a 220 ms
Si2493/57/34/15/04-EVB
D
and an external reset pushbutton. If
operation
contains
modes,
PEAK
two
ac. The
including
reset
Rev. 0.7
D
2.1.5. EEPROM Enable (FT Only)
Connecting JP34 and JP35 enables the optional
EEPROM, U5. See “AN93: Si2457/Si2434/Si2415/
Si2404 Modem Designer’s Guide” for programming
details.
2.1.6. Interface Selection
The serial interface of the Si2493/57/34/15/04-EVB can
be connected to a computer, terminal, embedded
system, or any other data terminal equipment (DTE) via
a standard RS-232 interface, USB interface, or through
a direct TTL serial interface.
The Si2493/57/34/15/04 can be tested as a standard
data modem by connecting the Si2493/57/34/15/04-
EVB to a personal computer or other DTE power supply
and a phone line. A PC can communicate with the
Si2493/57/34/15/04-EVB using a standard terminal
program, such as HyperTerm or ProComm.
Jumper settings determine how the Si2493/57/34/15/
04-EVB is connected to the DTE.
2.1.7. RS-232 Interface
This operation mode uses the standard factory jumper
settings illustrated in
MAX3237 transceiver interfaces directly with the TTL
levels available at the serial interface of the Si2493/57/
34/15/04 and, using internal charge pumps, makes
these signals compatible with the RS-232 standard. The
RS-232 transceiver on the Si2493/57/34/15/04-EVB can
communicate at rates between 300 bps and 1 Mbps.
This simplifies the connection to PCs and other data
terminal equipment (DTE). The signals available on the
Si2493/57/34/15/04-EVB
connector) are listed in Table 3.
2.1.8. USB Interface
The USB cable connects to J10 on the motherboard
and provides both data and power. Installing a jumper
on JP23 enables the USB interface and disables the
RS-232 interface. The USB interface is provided by
U12. A USB driver for this chip is available for most PC
and MAC operating systems on the CD.
G l o b a l I S O m o d e m - E V B
Si2493/57/34/15/04
Figure 1 on page 3
serial
interface
. The Maxim
(DB9
9