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Th e
Ltd
The L298 is a st r ong, useful dual-mot or dr iver IC but
it s t ough t o use by it self. The Solarbot ics Compact
L29 8 Mot or Dr iver Kit t ames t his beast , and put s it
int o a convenient package feat ur ing:
>6 t o 26V operat ion, 4A t ot al dr ive cur rent>Accessible 5V regulat ed volt age
>Mot or dir ect ion indicat or LEDs
>EMF prot ect ion diodes
>Small 40 mm (1 .527 ) square foot pr int
Tight & t idy - it s a great mot or int er face
DocRev: Jan 5 2008
Produced by
Compact
L2 9 8 Mo t o r Dr iver
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1 - Red print ed circuit board (PCB).
1 - L29 8 mot or dr iver chip
1 - LM2937 volt age regulat or chip1 - 22F capacit or
1 - 0 .1F capacit or
1 - 3 -posit ion t erminal block
2 - 2 -posit ion t erminal block
2 - 4 7k Enable pull-up resis t ors (Yellow / Violet / Orange / Gold)
2 - 2 .2k LED current limit r esist ors - (Red / Red / Red / Gold)
2 - Red LEDs2 - Green LEDs
8 - 1N58 18 Schot t ky EMF-prot ect ion Diodes
2 - 3 -posit ion int er face socket st r ips
We st rongly suggest you invent ory t he part s in your kit t o make sure you have all t he part s
list ed. If anyt hing is missing, cont act Solarbot ics Lt d. for r eplacement par t s informat ion.
Disclaimer of Liabil it y
Solarbot ics Lt d. is not responsible for any special, incident al, or consequent ial damages
result ing from any breach of warr ant y, or under any legal t heory, including lost profit s, downt ime,
good-will, damage t o or r eplacement of equipment or propert y, and any cost s or recovering of
any mat erial or goods associat ed wit h t he assembly or use of t his product . Solarbot ics Lt d.
reserves t he right t o make subst it ut ions and changes t o t his product wit hout prior not ice.
Par t s L is t
LM2937
Voltage
Regulator
L2 9 8 2 2 FCap
3-position
Terminal block
2-position
Terminal blocks
2 .2k
Resistors
3 -posit ion interface socket s1N 5 81 8 Diodes
Indicator
LEDsPCB
0.1F
Cap
Th e Co mpac t L 2 9 8 Mo t o r D r iv er
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In t r o duc t io nThe L298 chip is t he bigger brot her t o t he L293 chip (a popular
small-mot or dr iver IC), but t he L298 handles more cur rent ,
and more volt age - just what you need for t hose robot s t hat
need more power!
One of t he fir st r ealizat ions in robot ics is t hat making
somet hing move isn t an easy t ask. You simply can t t ake a
brain circuit and connect it t o a mot or and expect anyt hing t o
happen. The mot or will simply say HAH! at t he puny out put
signal from t he brains, and st ay st ill. What t he brain needs is
an enforcer. Muscle. Somet hing t o convince t he mot or t o do
t hings t he way t he brains want it t o be done.
There are many ways t o st r engt hen ( buffer ) a signal so it s
st rong enough t o dr ive a large load like a mot or. Transist or H-
br idge cir cuit s, buffer chips, and dedicat ed mot or dr iving chips
are all suit able candidat es, wit h t heir own benefit s andlimit at ions.
Were using t he well-proven L298 for t his design, as it has
pract ically all t he feat ures youd need in a good mot or dr iver,
including t hermal-shut down, meaning t hat it will slow down and
st op if over loaded (rat her t han melt ing down in a cat ast rophic
manner!).
Adding a low-drop out r egulat or let s you t ap off 5V for any
ot her circuit ry you may want t o dr ive, and t he indicat or LEDs
are always very useful when monit or ing t he behavior s of your
cir cuit .
Were quit e pleased on how well t he Compact L298 Mot orDr iver t urned out , and we hope it s as helpful t o you in your
designs as it has been for us!
Get t o work - youve got a mot or needing a dr iver!
Th e Co mpac t L 2 9 8 Mo t o r D r iv er
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Co ns t r uc t io n
St ep 2: The 2.2 k Resist or
The 2 .2k resist ors (red / r ed /
r ed / gold) are inser t ed int o
posit ions R3 and R4. Followt he same pr ocedur e as
previous.
These resist ors limit t he
cur r ent t o t he indicat or
LEDs.
St ep 1 : The 4 7k Resist or s
The 47k resist ors (yellow / purple /
orange / gold) (colorful, eh?) are
inser t ed int o t he spot s marked R1and R2. These t ie t he enable lines
t o a default on condit ion.
Snug t hem up close t o t he circuit
boar d, bend t he leads over, and
solder t hem int o place .
When done, clip off t he excessleads.
Act ually t o be proper your suppose
t o clip t he excess leads off t hen
solder t hem, but do what ever you
find easiest .
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St ep 4 : 0.1 F cap inst allat ion
This small 0 .1F cap provides high frequency noise filt er ing on t he
input side of t he regulat or. This cap is bi-polar and can be inst alled
eit her way at posit ion C2 .
Co ns t r uc t io n
St ep 5 : Inst all ing t he LEDs
There are four LEDs t o indicat e t he st at e of each out put . The logic is
fair ly obvious: The LED is on when t he out put is high. The LEDs must be
inst alled so t hat t he flat sides face each ot her. Or, simply make sure
t hat t he shor t er lead (t he cat hode) goes t o t he squar e pad.
We suggest inst alling one LED of each color
per side, so it s easy t o ident ify a single
mot or s rot at ion direct ion by color.
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St ep 6: Inst al l ing t he int er face
socket st r ips:
No magic here: Put t hem in and
solder t hem down in t heposit ions shown.
This will be where your input
signals will t ell t he L298 what t o
do. The socket s let you use
simple wir e jumpers. Or for a
permanent inst allat ion, solder
your int er face wires direct ly t ot he pads.
Co ns t r uc t io n
St ep 7: Inst alling t he Ter minal blocks
Put t hem in and solder t hem down, making sure t hat t he side holes
face out ward! It s kinda hard t o inst all mot or and power wir es int o
holes facing t he wrong way...
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Co ns t r uc t io n
St ep 8 : Inst al l ing t he 22 F
capacit or
Inst all t he capacit or wit h t he
shor t er lead going t o t hesquare pad.
This is also t he side of t he
capacit or wit h t he st r ipe (like
a long - symbol).
The round pad is marked as
+ , which receives t helonger capacit or lead.
Dont put t his capacit or in
backwards, as it ll go
BANG!
St ep 9: Inst al l ing t he 5V r egulat or
Please ignore t he t ext pr int ed on t he PCB for
t his component (t he 7805 ). We decided t o use
a bet t er volt age regulat or aft er t he cir cuit board
was manufact ured.
Inst all it in posit ion 7805 , making sure t he
met al flat par t wit h t he hole is above t he 7 805 .
The LM2 937 is a low-
volt age dropout , pin-for -
pin compat ible
r eplacement for t he
7805. Low-dropout
means it only needs
more t han 5.5 V t o give a
r egulat ed 5V out put ,
which is useful when
youre powering your
syst em from only a 6V
bat t ery.
Th e Co mpac t L 2 9 8 Mo t o r D r iv er
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Fin al c o n s t r uc t io n
St ep 10 : Inst alling t he L29 8
The t ime has come t o inst all t he
heart and soul of t he compact
mot or dr iver t he L29 8 chip.
The chip is orient ed wit h t he
met al t ab t owards t he back of
t he PCB. The chip has it s pins
keyed so t hat it would t ake a bit of
...skill... t o inst all it backwards!
If all has gone well, it should look somet hing like t his. Now
youre ready t o use it !
Th e Co mpac t L 2 9 8 Mo t o r D r iv er
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Per f o r man c e Ch ar ac t er is t ic sHer es t he nit t y grit t y on t he l298 chip as we t est ed it . You can find full
manufact urer s dat asheet s online at :
ht t p://downloads.solarbot ics.com/PDF/SGS_L298_mot or_dr iver_IC.pdf .
SGS Tho mpso n D at ash eet Cha r ac t er is t ic sLogic / Mot or supply maximum volt age . . . . . . . . . . . . . . . . . . . . . . . . . . 6V t o 50V
Input & enable line volt age r ange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7VPeak out put current (nonrepet it ive), t < = 1 00S (each channel) . . . . . . . . . . . 3 .0A
Cont inuous out put cur r ent (each channel). . . . . . . . . . . . . . . . . . . . . . . . . . . 2 .5A
Tot al cont inuous heat dissipat ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25W
Not e:
Wit hout modificat ion, t he maximum volt age input t o t he compact
mot or driver board is 2 6V, t his is t he maximum volt age t hat t he
r egulat or can handle. If t he volt age reg is r eplaced wit h a 7805 t hen
t he maximum volt age will be limit ed t o 30 V by t he 1N5818 diodes. If30V isn t enough and you want t o use 35V, r eplace t he diodes wit h
some 1N5819 diodes. Over 35V operat ion is rest r ict ed by t he volt age
r egulat or, but if you can work around t hat , t he next limit is 50V (t he
limit of t he L29 8!).
S o l ar bo t ic s Meas u r ed Ch ar ac t er is t ic s
Log ic Tabl e
Th e Co mpac t L 2 9 8 Mo t o r D r iv er
TestIC Volt age
9 V 1 2 V 18 .9 5V
Quiescent cur rent draw, IC enabled (mA)
Quiescent cur rent draw, IC disabled (mA)
31 .3 31 .6 31.9
5 .7 5.91 6.1
IC Vout (no load) 8 .3 11.25 18.09
IC input impedance (ohms) 127k 133k 140k
Single br idge peak out put cur rent (A) 2.78 2.92 Thermal Over loadVolt age drop across 8 ohm load (V) 6.63 9.24 15.16
Current delivered t o 8 ohm load (A) 0.829 1 .155 1 .895
Equivalent int ernal r esist ance (ohms) 2.86 2.39 2 .00
ENABLE L1 L2 Result ENABLE L3 L4 RESULT
L L L OFF L L L OFF
L L H OFF L L H OFF
L H L OFF L H L OFF
L H H OFF L H H OFF
H L L BRAKE H L L BRAKE
H L H FORWARD H L H FORWARD
H H L BACKWARD H H L BACKWARD
H H H BRAKE H H H BRAKE
PWM L L PULSE-BRK PWM L L PULSE-BRK
PWM L H FWD-SPD PWM L H FWD-SPD
PWM H L BCK-SPD PWM H L BCK-SPD
PWM H H PULSE-BRK PWM H H PULSE-BRK
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