LB1948MC
www.onsemi.com
6
Design Documentation
(1) Voltage magnitude relationship
There are no restrictions on the magnitude relationships between the voltages applied to V
CC
and IN1 to IN4.
(2) Parallel connection
The LB1948MC can be used as a single-channel H-bridge power supply by connecting IN1 to IN3, IN2 to IN4, OUT1 to
OUT3, and OUT2 to OUT4 as shown in the figure. (I
O
max = 1.6A, V
O
(sat) = 0.6V (typical) at I
O
= 800mA)
1V
CC
2 IN1
3 IN2
4 IN3
5 IN4
10
9
8
7
6
OUT1
OUT2
OUT3
OUT4
GND
LB1948MC
M
(3) Observe the following points when designing the printed circuit board pattern layout.
Make the V
CC
and ground lines as wide and as short as possible to lower the wiring inductance.
Insert bypass capacitors between V
CC
and ground mounted as close as possible to the IC.
Resistors of about 10K must be inserted between the CPU output ports and the IN1 to IN4 pins if the microcontroller
and the LB1948MC are mounted on different printed circuit boards and the ground potentials differ significantly.
(4) Penetration electric current
At the time of the next mode shift, a penetration electric current is generated in V
CC
-GND. There are not the
deterioration of the IC by), the destruction as follows 1Atyp per this penetration electric current (1ch, 1μs; but for the
stabilization of the power supply line of the IC is most recent, and, please can enter with a condenser.
(i) Forward (Reverse) ↔ Brake
(ii) Forward ↔ Reverse
(iii) Standby → Brake
In addition, the penetration electric current disappears when I put a wait mode of 10μs at the time of the change of the
Forward ↔ Reverse.
(5) Supplementary matter of the penetration electric current
According to (4), a penetration electric current cannot influence IC life.
Thermal Shutdown Temperature
(1) Thermal shutdown temperature
The thermal shutdown temperature Ttsd is 200 20C with
fluctuations.
(2) Thermal shutdown operation
The operation of the thermal shutdown circuit is shown in the
figure below.
When the chip temperature Tj is in the direction of increasing
(solid line), the output turns off at approximately 200C.
When the chip temperature Tj is in the direction of decreasing
(dotted line), the output turns on (returns) at approximately
125C.
100 120 140 160 180 200 220
0
14
12
10
8
6
4
2
V
CC
=
12V
100 C 220 C
220 C 100 C
Return
TSD operation
Chip temperature, Tj -- C
Output voltage, V
O
-- V
LB1948MC Thermal shutdown reference chart
