DESCRIPTION
The SS351AT and SS451A sensors are small, versatile digital Hall-effect devices that are operated by the magnetic field from a permanent magnet or an electromagnet. They are designed to respond to a either a North pole or a South pole.
These omnipolar sensors are sensitive and flexible devices designed to meet a wide range of potential applications. The SS351AT and SS451A have a typical operating point of 85 G at 25 °C [77 °F]. Because they can be operated by a North pole or a South pole, they do not require the magnet polarity to be identified, thus making the installation easier and potentially reducing the system cost.
FEATURES
Subminiature package size (SS351AT) supplied on tape and reel allows for a compact design with automated component placement, helping to reduce manufacturing costs
Simple activation from a North pole or a South pole and sensitive magnetics make this omnipolar product suitable in a variety of potential motion control, lid closure detection, and displacement sensing applications
Low voltage 3 Vdc capability helps reduce power consumption
Built-in reverse polarity protection protects the device from potential damage during installation
Thermally balanced integrated circuit provides for stable operation over a wide temperature range of -40° to
150 °C [-40 °F to 302 °F]
RoHS-compliant materials meet Directive 2002/95/EC
These sensors are available in two package styles. The SS351AT is available in the subminiature SOT-23 surface mount package; the SS451A is available in the leaded, flat TO- 92-style package. The SS351AT’s small size requires less PC board space, allowing it to be used in smaller assemblies. Its
3 Vdc capability allows for use in low voltage applications, promoting energy efficiency.
The SS351AT is available on tape and reel (3000 units per reel); the SS451A is available in a bulk package (1000 units per bag).
POTENTIAL APPLICATIONS
Commercial:
Speed and RPM (revolutions per minute) sensing in fitness equipment
Magnetic encoder for building access
Damper or valve position control in HVAC (heating, ventilation and air conditioning) equipment
Flow rate sensing in appliances and water softeners
Printer head position sensing
Industrial:
Flow rate sensing in industrial processes Robotic control (cylinder position monitoring) Float-based fluid level sensing
Medical:
Displacement sensor in hospital beds and medical equipment
Medication bin monitor on portable drug carts
Table 1. SS351AT/SS451A Specifications (At Vs=3.0 Vdc to 24 Vdc, 20 mA load, TA = -40 °C to 150 °C [-40 °F to 257 °F])
Characteristic |
Condition |
Minimum |
Typical |
Maximum |
Unit |
|
Supply voltage1: |
|
|
|
|
|
|
SS451A |
-40 °C to 150 °C [-40 °F to 302 °F] |
3 |
– |
24 |
Vdc |
|
SS351AT |
-40 °C to 125 °C [-40 °F to 257 °F] |
3 |
– |
24 |
||
|
||||||
SS351AT |
150 °C [302 °F] |
3 |
– |
12 |
|
|
Supply current |
Vsupply = 5 V at 25 °C [77 °F] |
– |
4.5 |
6 |
|
|
|
Vsupply = 3 V at 25 °C [77 °F] |
– |
3.5 |
5 |
mA |
|
|
|
– |
– |
9 |
|
|
Output Current |
– |
– |
– |
20.0 |
mA |
|
Vsat |
at 20 mA, gauss > Bop positive |
– |
– |
0.4 |
V |
|
|
or gauss < Bop negative |
|
|
|
|
|
Output leakage current |
gauss > Bop+ or < Bop- |
– |
– |
10 |
µA |
|
Output switching time: |
Vsupply = 12 V at 25 °C [77 °F], |
|
|
|
|
|
rise |
– |
– |
1.5 |
µs |
||
RL =1.6 KOhm, CL = 20 pF |
||||||
fall |
– |
– |
1.5 |
|
||
|
|
|||||
Thermal resistance: |
|
|
|
|
|
|
SS451A |
– |
– |
233 |
– |
°C/W |
|
SS351AT |
|
– |
303 |
– |
|
|
SS351AT/SS451A: |
|
|
|
|
|
|
Operate positive |
– |
35 |
85 |
135 |
gauss |
|
Operate negative |
|
-135 |
-85 |
-35 |
|
|
SS351AT/SS451A: |
|
|
|
|
|
|
Release positive |
– |
10 |
50 |
120 |
gauss |
|
Release negative |
|
-120 |
-50 |
-10 |
|
|
SS351AT/SS451A |
|
|
|
|
gauss |
|
Differential |
– |
5 |
35 |
80 |
||
|
||||||
Operating temperature |
– |
-40 [-40] |
– |
150 [302] |
°C [°F] |
|
Storage temperature |
– |
-40 [-40] |
– |
150 [302] |
°C [°F] |
Note 1: See Figure 1.
Table 2. SS351AT/SS451A Absolute Maximum Ratings1
Characteristic |
Minimum |
Typical |
Maximum |
Unit |
Supply voltage |
-28.0 |
– |
28.0 |
V |
Applied output voltage |
-0.5 |
– |
28.0 |
V |
Output current |
– |
– |
20 |
mA |
Magnetic flux |
– |
– |
no limit |
gauss |
Note 1: The magnetic field strength (gauss) required to cause the switch to change state (operate and release) will be as specified in the magnetic characteristics. To test the switch against the specified magnetic characteristics, the switch must be placed in a uniform magnetic field.
NOTICE
Absolute maximum ratings are the extreme limits that the device will withstand without damage to the device. However, the electrical and mechanical characteristics are not guaranteed as the maximum limits (above recommended operating conditions) are approached, nor will the device necessarily operate at absolute maximum ratings.
Figure 1. SS351AT Rated Supply Voltage |
Figure 2. Current Sinking Output Block Diagram |
|
|
2 www.honeywell.com/sensing