ULN2003
NOTICE ON PRODUCT USE
LINEAR INTEGRATED CIRCUIT
(1) The absolute maximum ratings of the IC are a set of ratings that must not be exceeded, even for a moment.
Exceeding the rating(s) may cause the device breakdown, damage or deterioration, and may cause injury by
explosion or combustion.
(2) To ensure that a large current does not continuously flow in case of over current and/or IC failure, an
appropriate power supply fuse should be used. The IC will fully breakdown under conditions that exceed its absolute
maximum ratings. For example, when the wiring is routed improperly or when an abnormal pulse noise occurs from
the wiring or load, causing a large current to continuously flow and the breakdown can lead smoke or ignition. To
minimize the effects of the flow of a large current in case of breakdown, careful settings, such as fuse capacity,
fusing time and insertion circuit location, are required.
(3) If the design includes an inductive load such as a motor coil, the current resulting from the inrush current at
power ON or the negative current resulting from the back electromotive force at power OFF can cause device
malfunction or breakdown, so a protection circuit need to be incorporated into the design. IC breakdown may cause
injury, smoke or ignition. When the power supply is unstable, the build-in protection function may not operate,
causing IC breakdown. IC breakdown may cause injury, smoke or ignition.
(4) Do not mount devices in the wrong orientation or incorrectly. Make sure that the positive and negative
terminals of power supplies are connected properly. Otherwise, the current or power consumption may exceed the
absolute maximum rating, and may cause the device breakdown, damage or deterioration, and may result injury by
explosion or combustion. In addition, do not use any device that is applied the current with inserting in the wrong
orientation or incorrectly even just one time.
(5) Carefully select external components (such as inputs and negative feedback capacitors) and load components
(such as speakers), for example, power amp and regulator. If there is a large amount of leakage current such as
input or negative feedback condenser, the IC output DC voltage will increase. If this output voltage is connected to a
speaker with low input withstand voltage, over-current or IC failure can cause smoke or ignition. (The over-current
can cause smoke or ignition from the IC itself.) In particular, please pay attention to the Bridge Tied Load (BTL)
connection type IC that inputs output DC voltage to a speaker directly.
POINTS TO REMEMBER ON PRODUCT USE
(1) Heat Radiation Design
When IC is used with large current flow such as power amp, regulator or driver, the heat radiation consideration
should be designed carefully, not to exceed the specified junction temperature (Tj) at any time and condition. An
inadequate IC heat radiation design can lead to decrease in IC life, deterioration of IC characteristics or IC
breakdown. Meanwhile, also should take into considerate the effect of IC heat radiation with peripheral components.
(2) Back-EMF
When a motor rotates in the reverse direction, stops or slows down abruptly, a current flow back to the motor’s
power supply due to the effect of back-EMF. The device’s motor power supply and output pins might be exposed to
conditions excessing absolute maximum ratings, when the current sink capability of the power supply is small. To
avoid happening, take the effect of back-EMF into consideration in system design.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
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QW-R113-001.J
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