SP2526 EVALUATION BOARD
The next two sections describe the
SP2526
Board
Layout and Using the
SP2526 Evaluation
Boards.
A table of
SP2526
Pin Assignments is
also included with details on Input/Output pin
function. A
SP2526 Evaluation Board
List
of Materials table is provided with some
manufacturers part numbers to use as a
reference. Finally, a schematic and drawings of
the PC Board Layout are included of the
SP2526 Evaluation Board.
per input or output connection versus using
surface-mount size 0805 ferrite beads which
yielded 5mΩ per input or output connection.
USING THE EVALUATION BOARD
The
SP2526 Evaluation Board
can be connected
to a power supply using a pair of wires soldered
to the solder pads marked provided “VIN” and
“GND”. It is good practice to not switch power
on until power connections are made to the
evaluation board.
Powering Up & Using the SP2526 Circuit
V
IN
— U1-7 — Solder wire to VIN solder
pad on component side of board and connect to
external Power Supply positive. V
IN
= +3.0V
to +5.5V. Connect Voltmeter positive or
Oscilloscope probe to V
IN
test point post to
monitor actual voltage input to PC board.
GND — U1-6 — Solder wire to GND solder
pad on component side of board and connect to
external Power Supply negative. Connect
Voltmeter negative or Oscilloscope probe
ground to GND test point post to monitor
actual voltage input to PC board.
OUTA — U1-8 — Solder wire to OUTA solder
pad on component side of board and connect
to external load. Connect Voltmeter positive
or Oscilloscope probe to OUTA test point post
to monitor actual voltage output at the PC board.
GNDA — Solder wire to GNDA solder pad
on component side of board and connect to
external LoadA return. Connect Voltmeter
negative or Oscilloscope probe ground to
GND test point post to monitor actual voltage
input to PC board.
OUTB — U1-5 — Solder wire to OUTB solder
pad on component side of board and connect
to external load. Connect Voltmeter positive
or Oscilloscope probe to OUTB test point post
to monitor actual voltage output at the PC board.
GNDB — Solder wire to GNDB solder pad on
component side of board and connect to external
LoadB return. Connect Voltmeter negative or
Oscilloscope probe ground to GND test point post
to monitor actual voltage input to PC board.
© Copyright 2000 Sipex Corporation
BOARD LAYOUT
The
SP2526 Evaluation Board
has been
designed to easily and conveniently provide
access to all Inputs and Outputs of the
SP2526
device under test. Position the board with the
silkscreen lettering upright (see
Figure 1
Component Layout) and you will see the
SP2526
SOIC labeled U1 in the center right of
the board, and around it the Capacitors C1,2,3
and Ferrite Beads F1-4 forming the Dual USB
Supervisory Switch.
The
SP2526 Evaluation Board
provides solder
pads to connect wires to an external power
supply and load, as well as Test Point Posts
to monitor the Input and Output Voltages at
these connections to the
SP2526.
The
SP2526
PC Board Layout has been designed with low
resistance input and output connections of 2mΩ
each to provide the lowest On-Resistance for
utilizing the USB Switch.
The PC Layout is given in Figures 1-3 for the
user as an aid in designing a low resistance USB
switch on a PC board. The PC board used has 1oz
Copper with V
IN
, Ground, V
OUT
traces of at least
0.1inch width for 5mΩ/inch or looked at another
way as 0.5mΩ/square. This means to maintain a
trace resistance of only 2mΩ, you need to have
only 4 squares of trace from one end to another.
Resistance is further reduced by some additional
wide V
IN
, Ground and V
OUT
connections on the
bottom side of the PC board which are connected
to the top side with large through-hole
connections. For best results with on-resistance
in the ferrites used for EMI suppression in the
Output and Ground connections, through-hole
ferrite beads were used for F1-4, yielding 2mΩ
SP2526EB/02
SP2526 Evaluation Board Manual
2
V
DD
— Connect to a second Power Supply 5V
(or 3.3V) connection – V
DD
provides the pull-up
voltage for Enables ENA & ENB and Flags
FLGA & FLGB. This separate supply connection
allows the user to separately measure V
IN
supply
current.
GND — Second Power Supply GND Connection –
connect to supply return for V
DD
.
ENA — U1-1 —Enable A Input must be
connected High or Low – open produces
unstable behavior, so be sure to connect V
DD
to
an external 3.3V or 5V source. See
Table 1
Enable Jumpers for information on Enable
Jumper J1 position. The user can actively
control Switch A with an external Logic signal.
FLGA — U1-2 — Flag A output is open drain
and has a pull-up to V
DD
(which should be
connected to an external source). Connect
FLGA to voltmeter or oscilloscope to monitor
Switch A for flags when Low if Under-voltage,
Over-current or Over-temperature occurs.
.
ENB — U1-4 — Enable B Input must be
connected High or Low – open produces
unstable behavior, so be sure to connect V
DD
to an external 3.3V or 5V source. See
Table 1
Enable Jumpers for information on Enable
Jumper J2 position. The user can actively
control Switch B with an external Logic signal.
FLGB — U1-3 — Flag B output is open drain
and has a pull-up to V
DD
(which should be
connected to an external source). Connect
FLGB to voltmeter or oscilloscope to monitor
Switch B for flags when Low if Under-voltage,
Over-current or Over-temperature occurs.
Using the Enable Jumbers J1 & J2
The jumpers J1& J2 have 2 positions, as
described below. Connecting a logic level to
the ENA or ENB test point post will override
the pull-up or pull-down to actively control
the switch.
Part
Number
SP2526-1
SP2526-2
Enable
Active
High
Active
Low
Enable A
J1 Position
1-2
Pull-up
2-3
Pull-down
Enable B
J2 Position
1-2
Pull-up
2-3
Pull-down
Table 1. Enable Jumpers J1 & J2
SP2526EB/02
SP2526 Evaluation Board Manual
© Copyright 2000 Sipex Corporation
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