3235
DUAL-OUTPUT
HALL-EFFECT SWITCH
3235
DUAL-OUTPUT
HALL-EFFECT SWITCH
Type UGN3235K Hall-effect sensors are bipolar integrated circuits
designed for commutation of brushless dc motors, and other rotary
encoding applications using multi-pole ring magnets. The device
features two outputs which are independently activated by magnetic
fields of opposite polarity.
Each sensor IC includes a Hall voltage generator, two Schmitt
triggers, a voltage regulator, output transistors, and on-board reverse
polarity protection. The regulator enables these devices to operate
from voltages ranging between 4.5 V and 24 V. On-chip compensation
circuitry stabilizes the switch points over temperature.
Each open-collector output is independently operated by the
proper amount and polarity of incident magnetic flux. Output 1 re-
sponds only to the positive flux from the south pole of a magnet,
Output 2 to the negative flux from the north pole of a magnet. When
the sensor experiences the field of a south magnetic pole greater than
the maximum operate point of Output 1, that output switches to the
LOW state and Output 2 is unaffected. When the incident flux falls
below the minimum release point for Output 1, that output returns to
the HIGH state and Output 2 remains unchanged.
Output 2 independently responds in the same manner to the
negative flux from the north magnetic pole of a magnet. Figure 1
shows a zone in the region of 0 G, t
H
, where both outputs are in the
HIGH or OFF state. This constitutes a delay that is independent of
rate of change of the incident magnetic field and ensures that both
outputs are never ON simultaneously. This is an essential feature for
driving brushless dc motors with a minimum of reactive transient
currents.
The UGN3235K is supplied in a four-pin plastic single in-line
package (SIP).
Data Sheet
27633A*
V
CC
X
1
2
3
4
OUTPUT1
OUTPUT2
Dwg. PH-007
Pinning is shown viewed from branded side.
ABSOLUTE MAXIMUM RATINGS
at T
A
= +25
°
C
Power Supply, V
CC
. . . . . . . . . . . . . . . .
25 V
Reverse Battery Voltage, V
RCC
. . . . .
-30 V
Magnetic Flux Density, B . . . . . .
Unlimited
Output OFF Voltage, V
OUT
. . . . . . . . . .
25 V
Output ON Current, I
OUT
. . . . . . . . . .
50 mA
Operating Temperature Range,
T
A
. . . . . . . . . . . . . . . .
-20
°
C to + 85
°
C
Storage Temperature Range
T
S
. . . . . . . . . . . . . . . .
-65
°
C to +150
°
C
GROUND
SUPPLY
FEATURES
s
Reliable and Rugged Magnetic Sensing Switch
s
Two Outputs Independently Switched by North and South Poles
s
Independent Actuation of Outputs Minimizes Inductive-Load
Reactive Transient
s
Built-in Hysteresis Minimizes Interference from Stray Fields
s
Operates from 4.5 V to 24 V
s
Outputs Compatible with All Logic Levels
s
On-Board Reverse Polarity Protection
s
Open-Collector, Active-Low Outputs
Always order by complete part number:
UGN3235K
.
3235
DUAL-OUTPUT
HALL-EFFECT SWITCH
FUNCTIONAL BLOCK DIAGRAM
1
V
CC
2
OUTPUT
1
REG.
X
3
4
OUTPUT 2
GROUND
Dwg. FH-003A
ELECTRICAL CHARACTERISTICS at T
A
= +25
°
C (unless otherwise noted).
Characteristic
Supply Voltage
Output Saturation Voltage
Output Leakage Current
Supply Current
Output Rise Time
Output Fall Time
Symbol
V
CC
V
OUT(SAT)
I
OFF
I
CC
t
r
t
f
V
CC
= 24 V, I
OUT
= 20 mA
V
OUT
= 24 V, V
CC
= 24 V
V
CC
= 24 V, Output Open
V
CC
= 14 V, R
L
= 820
Ω,
C
L
= 20 pF
V
CC
= 14 V, R
L
= 820
Ω,
C
L
= 20 pF
Test Conditions
Min.
4.5
—
—
—
—
—
Typ.
—
160
—
6.0
0.04
0.18
Max.
24
400
1.0
8.0
0.4
0.4
Units
V
mV
µA
mA
µs
µs
MAGNETIC CHARACTERISTICS at V
CC
= 4.5 V to 24 V
Characteristic
Operate Point, B
OP
Test Conditions
T
A
= +25°C
T
A
= -20°C to +85°C
Release Point, B
RP
T
A
= +25°C
T
A
= -20°C to +85°C
Hysteresis, B
hys
T
A
= +25°C
T
A
= -20°C to +85°C
Output
Q1
Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1 & Q2
Q1 & Q2
Min.
50
-175
35
-200
25
-160
15
-190
15
15
Max.
175
-50
200
-35
160
-25
190
-15
100
110
Units
G
G
G
G
G
G
G
G
G
G
115 Northeast Cutoff, Box 15036
W
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 1989, 1995 Allegro MicroSystems, Inc.
3235
DUAL-OUTPUT
HALL-EFFECT SWITCH
SWITCH POINTS vs. TEMPERATURE
150
TRANSFER CHARACTERISTICS
100
B
OPS
B
RPS
SWITCH POINT IN GAUSS
25 V
MAX
V OUT(OFF)
B OP2
B OP1
50
0
-50
B
RPN
B
OPN
-100
BRP2
BRP1
VOUT(SAT)
OUTPUT VOLTAGE
0
-150
-50
-25
0
25
50
75
100
125
150
-B
0
+B
AMBIENT TEMPERATURE IN
°C
Dwg. GH-027-1
MAGNETIC FLUX
Dwg. GH-043A
APPLICATIONS
Figure 1 illustrates a method of sensing the presence
of either a north or south magnetic pole. Because the
UGN3235K is an open-collector device, it is possible to
directly connect (wired OR) the two outputs. This causes
the output to go LOW when either a north pole or south
pole of sufficient magnitude is sensed. The device
connected in this manner suits many applications, ranging
from doubling the resolution of a ring-magnet encoder, to
zero-crossing detection.
V
CC
4.5 V to 24 V
+B (SOUTH)
B OP1
MAGNETIC FLUX
BRP1
0
B OP2
–B (NORTH)
B RP2
Q1
OUTPUTS
ON
Q2
OFF
X
V
CC
20 mA
DEAD
TIME
OFF
DEAD
TIME
ON
1
ON
OFF
2
Dwg. WH-009-1
SIGNAL
OUTPUT
3
4
FIGURE 2
ZERO-CROSSING DETECTION
Dwg. EH-010
FIGURE 1
BIPOLAR DETECTOR
Figure 2 shows that there is a “dead time” approxi-
mately centered around 0 G. Thus, by sensing the HIGH
portion of the UGN3235K wired-OR output, the zero-
crossing can be detected.
Figure 3 shows that the UGN3235K makes it possible
to implement a very efficient brushless dc motor control
using a minimum number of components. Referring again
to Figure 1, the dead time (where both drivers are OFF)
allows the motor coil field to decay sufficiently. This
avoids both excessive reactive voltages and the magnetic
drag resulting from the motor coils working in opposition
to each other.
3235
DUAL-OUTPUT
HALL-EFFECT SWITCH
0.1
µF
V
CC
1 kΩ
VCC
5 V to 24 V
X
1 kΩ
1
2N4356
2
4
2N4356
3
Dwg. EH-009
FIGURE 3
MOTOR DRIVER
SENSOR LOCATION
(±0.005” [0.13mm] die placement)
ACTIVE AREA DEPTH
0.015"
0.38 mm
NOM
280
GUIDE TO INSTALLATION
0.106"
2.70 mm
TEMPERATURE IN
°C
260
0.058"
1.47 mm
240
220
A
BRANDED
SURFACE
1
2
3
4
200
Dwg. MH-001-1B
0
5
10
15
20
Dwg. GA-001
TIME IN SECONDS
All Hall effect integrated circuits are susceptible to mechanical stress effects. Caution
should be exercised to minimize the application of stress to the leads or the epoxy
package. Use of epoxy glue is recommended. Other types may deform the epoxy
package.
To prevent permanent damage to the Hall cell, heat-sink the leads during hand
soldering. Recommended maximum conditions for wave soldering are shown in the
graph above.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
3235
DUAL-OUTPUT
HALL-EFFECT SWITCH
Dimensions in Inches
(controlling dimensions)
0.208
0.203
Dimensions in Millimeters
(for reference only)
5.28
5.16
45°
0.063
0.059
45°
1.60
1.50
0.138
0.133
45°
0.085
MAX
3.51
3.38
45°
2.16
MAX
1
2
3
4
0.033
1
2
3
4
0.84
0.600
0.560
0.015
15.24
14.23
0.38
SEE NOTE
SEE NOTE
0.016
0.050
BSC
Dwg. MH-009C in
0.41
1.27
BSC
Dwg. MH-009C mm
NOTES: 1. Tolerances on package height and width represent allowable mold offsets. Dimensions given are measured at the widest point (parting line).
2. Exact body and lead configuration at vendor’s option within limits shown.
3. Height does not include mold gate flash.
4. Recommended minimum PWB hole diameter to clear transition area is 0.035” (0.89 mm).
5. Where no tolerance is specified, dimension is nominal.
Allegro MicroSystems, Inc. reserves the right to make, from time to time, such departures from
the detail specifications as may be required to permit improvements in the design of its products.
Components made under military approvals will be in accordance with the approval requirements.
The information included herein is believed to be accurate and reliable. However, Allegro
MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or
other rights of third parties which may result from its use.
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