SP503 Datasheet, PDF (20/29 Pages) Sipex Corporation – Multiprotocol Transceiver

SP502/SP503 EVALUATION BOARD
The SP502/SP503 Evaluation Board (EB) Is
designed to offer as much flexibility to the user
as possible. Each board comes equipped with an
80-pin QFP Zero-Insertion Force socket to
allow for testing of multiple devices. The con-
trol lines and inputs and outputs of the device
can be controlled either manually or via a data
bus under software control. There is a 50-pin
connector to allow for easy connection to an
existing system via a ribbon cable. There are
also open areas on the PC board to add addi-
tional circuitry to support application-specific
requirements.
Manual Control
The SP502/SP503EB will support both the
SP502 or SP503 multi-mode serial transceiv-
ers. When used for the SP502, disregard all
notation on the board that is in [brackets] . The
SP502 has a half-duplex connection between
the RxT receiver and the TT driver. Due to this
internal connection, the RxT receiver inputs can
be accessed via the TT(a) and TT(b) pins. If the
user needs separate receiver input test pins,
jumpers JP1 and JP2 can be inserted to allow for
separate receiver inputs located at SCT(a) and
SCT(b). The corresponding TTL output for this
receiver is labeled as SCT. This test point is tied
to pin 79 of the SP502 or SP503. Pin 7 of the
evaluation board is connected to the DIP switch,
and is labeled as (SCTEN). When used with the
SP502, this pin should be switched to a low
state. When the evaluation board is used with
the SP503, pin 7 is a tri-state control pin for the
SCT receiver.
The transceiver I/O lines are brought out to test
pins arranged in the same configuration as shown
elsewhere in this data sheet. A top layer
silk-screen shows the drivers and receivers to
allow direct correlation to the data sheet. The
transmitter and receiver decode bits are tied
together and are brought out to a DIP switch for
manual control of both the driver and receiver
interface modes. Since the coding for the drivers
and receivers is identical, the bits have been tied
together. The DIP switch has 7 positions, four of
which are reserved for the TDEC/RDEC control
and the other three are used as tri-state control
pins. The labels that are in [brackets] apply only
to the SP503. If a logic one is asserted, the
corresponding red LED will be lit. If a zero is
asserted, the corresponding red LED will not
be lit.
Software Control
A 50-pin connector brings all the analog and
digital I/O lines, V_CC, and GND to the edge of the
card. This can be wired to the user’s existing
design via a ribbon cable. The pinout for the
connector is described in the following section.
When the evaluation board is operated under
software control, the DlP switch should be set
up so that all bits are LOW (all LEDs off). This
will tie 20kΩ pulldown resistors from the inputs
to ground and let the external system control the
state of the control inputs.
Power and Ground Requirements
The evaluation board layout has been optimized
for performance by using basic analog circuit
techniques, The four charge-pump capacitors
must be 22µF (16V) and be placed as close to the
unit as possible; tantalum capacitors are sug-
gested. The decoupling capacitor must be a
minimum of 1µF; depending upon the operating
environment, 10µF should be enough for worst
case situations. The ground plane for the part
must be solid, extending completely under the
package. The power supplies for the device
should be as accurate as possible; for rated
performance ±5% is necessary. The power sup-
ply current will vary depending upon the se-
lected mode, the amount of loading and the data
rate. As a maximum, the user should reserve
200mA for I_CC. The worst-case operating mode
is RS-485 under full load of six (6) drivers
supplying 1.6V to 54Ω loads. The power and
ground inputs can be supplied through either the
banana jacks on the evaluation board (Red = V_CC
= +5V±5%; Black = GND) or through the con-
nector.
For reference, the 80-pin QFP Socket is a
TESCO part number FPQ-80-65-09A. The
50-pin connector is an AMP part number
749075-5.
Date: 7/29/04
SP503 Multiprotocol Transceiver
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© Copyright 2004 Sipex Corporation