Datasheet

1
2
3
4
8
COM
7
6
5
16
GND
9
15
14
13
12
11
10
1B
2B
3B
4B
7B
6B
5B
1C
2C
3C
4C
7C
6C
5C
GND
8B
8C
18
17
Time (s)
Output voltage - V
-0.004 0 0.004 0.008 0.012 0.016
0
1
2
3
4
5
6
7
8
9
10
11
12
13
D001
Time (s)
Output voltage - V
-0.004 0 0.004 0.008 0.012 0.016
0
2
4
6
8
10
12
14
D001
ULN2803A
www.ti.com SLRS049G –FEBRUARY 1997–REVISED JANUARY 2015
10.2.3 Application Curves
The following curves were generated with ULN2803A driving an OMRON G5NB relay – V
in
= 5.0V; V
sup
= 12 V &
R
COIL
= 2.8 kΩ
Figure 14. Output Response with Figure 15. Output Response with
Activation of Coil (Turn On) De-activation of Coil (Turn Off)
11 Power Supply Recommendations
This part does not need a power supply; however, the COM pin is typically tied to the system power supply.
When this is the case, it is very important to make sure that the output voltage does not heavily exceed the COM
pin voltage. This will heavily forward bias the fly-back diodes and cause a large current to flow into COM,
potentially damaging the on-chip metal or over-heating the part.
12 Layout
12.1 Layout Guidelines
Thin traces can be used on the input due to the low current logic that is typically used to drive ULN2803A. Care
must be taken to separate the input channels as much as possible, as to eliminate cross-talk. Thick traces are
recommended for the output, in order to drive whatever high currents that may be needed. Wire thickness can be
determined by the trace material's current density and desired drive current.
Since all of the channels currents return to a common emitter, it is best to size that trace width to be very wide.
Some applications require up to 2.5 A.
12.2 Layout Example
Figure 16. Package Layout
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