A3250ELT-T ALLEGRO [Allegro MicroSystems], A3250ELT-T Datasheet - Page 10

• Manufacturer Part Number: A3250ELT-T
• Description: Field-Programmable, Chopper-Stabilized Unipolar Hall-Effect Switches
• Manufacturer: ALLEGRO [Allegro MicroSystems]

A3250
A3251
The pulse sequences consist of the following groups of pulses:
1. An enable sequence.
2. A bitfield address sequence.
3. When permanently setting the bitfield, a long V
4. When permanently setting the bitfield, the level of V
Bitfields that are not set are evaluated as zeros. The bitfield-level
fuses for 0 value bitfields are never blown. This prevents inad-
ing pulse. (Note: Blown bit fuses cannot be reset.)
be allowed to drop to zero between each pulse sequence, in
order to clear all registers. However, when provisionally set-
ting bitfields, V
sequences, in order to maintain the prior bitfield settings while
preparing to set additional bitfields.
and
CC
must be maintained at V
V
V
V
V
V
V
PM
PH
PL
PM
PH
PL
0
0
V+
Figure 2. Pulse sequence to provisionally try calibration value 5.
V+
Figure 3. Pulse sequence to permanently encode calibration value 5 (101 binary, or
bitfield address 3 and bitfield address 1).
Enable
Enable
PL
between pulse
PH
Field-Programmable, Chopper-Stabilized,
Try 5
Encode 00100
fuse-blow-
10
Address
Address
CC
must
2
(4
10
)
Blow
Monitoring
vertently setting the bitfield to 1. Instead, blowing the device-
level fuse protects the 0 bitfields from being accidentally set in
the future.
When provisionally trying the calibration value, one pulse
sequence is used, using decimal values. The sequence for setting
the value 5
When permanently setting values, the bitfields must be set indi-
vidually, and 5
set to 1 (000100
which is 1
sequences for permanently setting the calibration value 5 are
shown in figure 3. The final V
period, enough to blow the corresponding bitfield-level fuse.
Optional
Unipolar Hall-Effect Switches
Clear
t
10
10
Enable
). Bit 2 is ignored, and so remains 0.Two pulse
is shown in figure 2.
10
2
Encode 00001
, which is 4
must be programmed as binary 101. Bit 3 is
Address
2
115 Northeast Cutoff, Box 15036
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
Blow
(1
10
10
)
PH
), then bit 1 is set to 1 (000001
pulse is maintained for a longer
t
2
10
,