Allegro MicroSystems A1569 User Manual page 2

the A1569 as shown in Figure 2), pre-installed on the back side
of the board (the opposite side as the A1569 as shown in Figure
3), or with no LED installed (for the case where the LED will be
remotely located from the A1569).
Figure 2: A1569 Proto Board – Top
Figure 3: A1569 Proto Board – Bottom
Basic Connections
The basic connections are boxed and labeled P1 on the front of
the board (see the upper-left corner of Figure 2). This is where
the power and ground connections are made. By turning the
board over, additional labelling can be seen (see the upper-right
corner of Figure 3).
• Ground should be connected to the square pad (which has no
additional labelling).
• VIN should be connected to the middle pad, which is round
and is labeled on the bottom.
• If the application requires the Hall Element be selectively
enabled and disabled, then a connection to SEN_EN can be
made to the remaining round pad.
Connecting Remote LEDs
The A1569 Proto Board provides through-holes for connecting a
string of LEDs which can be mounted remotely from the A1569
Proto Board. To make use of this feature, no other LED should be
mounted on the A1569 Proto Board.
The through-holes for connecting the remote LED string are
boxed and labeled LA on the front of the board (see the lower-left
corner of Figure 2).
• The cathode of the remote LED string should be connected
to the hole with the square pad (which has no additional
labelling).
• The anode of the remote LED string should be connected to
the remaining hole with the round pad (labeled LA on the back
of the board; see Figure 3).
Connecting an External Hall Switch
It is possible to override the A1569 internal Hall element and
turn on the LED output current by driving the EXT input of the
A1569. This allows for a second sensing point, remote from
the A1569, to control the LED string connected to the A1569.
Allegro provides a separate A1126 Proto Board as a mate to the
A1569 Proto Board for this application. Contact your Allegro
sales representative for information on obtaining one of these
boards.
The connections for the external Hall element is boxed and
labeled on the bottom of the A1569 Proto Board (see right-hand
side of Figure 3).
The connections to the A1126 Proto Board are as follows:
• The grounds of the two boards should be connected together
using the square pads (which have no additional labelling).
• The OUT of the A1126 Proto Board should be connected to
EXT of the A1569 Proto Board. Both of these connections are
labeled on the bottom side of their respective boards and are
the middle connections with the round pads.
• The VOUT of the A1569 Proto Board should be connected to
the VIN of the A1126 Proto Board using the remaining round
pads. Both are labeled on the bottom side of their respective
boards.
Refer to the A1126 Proto Board User's Guide for more informa-
tion.
Worcester, Massachusetts 01615-0036 U.S.A.
Allegro MicroSystems, LLC
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
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