TA8428K/FG
TOSHIBA BIPOLAR LINEAR INTEGRATED CIRCUIT
SILICON MONOLITHIC
TA8428K, TA8428FG
DC MOTOR FULL-BRIDGE (H-BRIDGE) DRIVER ICs
(Forward/reverse switching driver ICs)
The TA8428K, TA8428FG is Full Bridge Driver IC for Brush
Motor Rotation Control.
Forward Rotation, Reverse Rotation, Stop and Braking
operations are available.
TA8428K
FEATURES
Output Current : TA8428K
TA8428FG
1.5 A (AVE.), 3.0 A (PEAK)
0.8 A (AVE.), 2.4 A (PEAK)
TA8428FG
4 modes (forward/reverse/short brake and stop) are available
with 2 TTL compatible inputs control. Free-wheeling diodes
for back-EMF protection are equipped.
Thermal shutdown and overcurrent protection circuits
Operating voltage range: V
CC
= 7.0 V to 27.0 V
The TA8428FG is RoHS compatible.
The TA8428K is a Sn-plated product. (The Pb-containing materials
with a high melting point that are exempted from RoHS directives are used inside the IC.)
Weight
HSIP7−P−2.54
: 1.88 g (Typ.)
HSOP20−P−450−1.00 : 0.79 g (Typ.)
About solderability, following conditions were confirmed
•
Solderability
(1) Use of Sn-37Pb solder Bath
· solder bath temperature: 230°C
· dipping time: 5 seconds
· the number of times: once
· use of R-type flux
(2) Use of Sn-3.0Ag-0.5Cu solder Bath
· solder bath temperature: 245°C
· dipping time: 5 seconds
· the number of times: once
· use of R-type flux
Terminals of TA8428 written below are sensitive to electrostatic discharge. When handling this product, ensure that the
environment is protected against electrostatic discharge by using an earth strap, a conductive mat and an ionizer. Ensure
also that the ambient temperature and relative humidity are maintained at reasonable levels.
Terminals which are sensitive to electrostatic discharge: No. 1 and 2 (TA8428K）, No. 8 and 9 (TA8428FG)
The IC should be installed correctly. Otherwise, the IC or peripheral parts and devices may be degraded or permanently
damaged.
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TA8428K/FG
BLOCK DIAGRAM
TA8428K
TA8428FG
PIN FUNCTION
PIN No.
K
1
2
FG
8
9
SYMBOL
IN1
IN2
FUNCTIONAL DESCRIPTION
TTL compatible control inputs.
(PNP type low active comparator inputs)
Connection pin for a DC motor, which can sink and
source currents of up to 1.5 A (TA8428K) or 0.8 A
(TA8428FG). Two free-wheeling diodes are internally
connected to this pin; one is between this pin and GND
and the other is between this pin and V
CC
.
GND terminal
3
15
OUTA
4
5
Fin
16
GND
OUT
A
Connection pin for a DC motor. This pin has the same
function as the OUT A pin.
Non connection
Supply voltage terminal for control and motor drive.
6
7
Other pin
1, 3
N.C
V
CC
MULTI-PROTECTION CIRCUITS
TA8428K, TA8428FG has 2 build−in protective functions which work independently.
These circuit operations are as follows.
Note 1: These protection features are provided to temporarily avoid abnormal conditions such as output short circuits
and are not guaranteed to prevent the IC from being damaged.
Note 2: These features do not operate outside the guaranteed operating ranges and the IC may be permanently
damaged in case of output short circuits.
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TA8428K/FG
THERMAL SHUTDOWN (TSD)
•
Basic Operation
When the junction temperature (chip temperature) is equal to or lower than the TSD threshold, output signals
are controlled by input signals. However, when the junction temperature exceeds the threshold, output pins
are put into a high-impedance state regardless of input signals.
•
Functional Description
Temperature sensing is performed by monitoring the V
F
voltage at an on-chip diode. When V
F
is low
compared to the internal reference voltage, the TSD circuit sends a signal to the control logic to turn off the
output transistors. Otherwise, the control logic is controlled by the IN1 and IN2 inputs.
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TA8428K/FG
OVERCURRENT PROTECTION (ISD)
•
Basic Operation
When output sink and source currents (TA8428K: at pins 3 and 5; TA8428FG: at pins 15 and 16) are equal to
or lower than the overcurrent threshold, output signals are controlled by input signals. However, when any of
these currents exceed the threshold, outputs are turned on and off periodically as shown in Figure 1.
Figure 1 Basic Operation
•
Functional Description
The output current is sensed by monitoring the V
BE
voltage at each output transistor. The current sensor is
connected to each output transistor and to the ISD circuit. If a current higher than the overcurrent threshold
flows through any one of the four output transistors, the ISD circuit is activated. This circuit incorporates a
timer. If the overcurrent condition persists for 20
μs
(typ.), the output is switched to a high-impedance state.
Then, it is turned back on after 80
μs
(typ.). If the overcurrent condition still persists at this time, the ISD
circuit repeats this overcurrent protection sequence until the overcurrent condition is removed.
This circuit cannot protect the device from all types of over currents. If the outputs are short-circuited to
each other or to ground, the IC may be permanently damaged before the protection circuit is activated.
Therefore, a resistor or fuse should be connected in the supply voltage line.
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TA8428K/FG
INTERNAL CIRCUIT
TA8428K
TA8428FG
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2010-02-23
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