NJM3548TA2 参数 Datasheet PDF下载

NJM3548

s

APPLICATIONS INFORMATION

Important application areas are:

• Programmable logic control systems.

• Relay control.

• Hydraulic valves.

• Intelligent interfaces between microprocessors and loads.

• Robot techniques.

• Print head drivers.

• High-current stepper motor drivers.

Transient protection

1. Keep V

CC

and GND leads as short as possible. Use different supplies if possible.

2. Connect a filter capacitor close to the circuit. Recommended filter capacitor between V

CC

and GND is 6.8

µF,

of

tantalum type. A ceramic capacitor in parallel will improve high frequency decoupling. Typical values range from

0.002

µF

to 0.1

µF.

In an application having a highly stable supply and short power leads to the driver a low

leakage electrolytic type can be used, which is less expensive.

3. Connect Input and Error via pull-up resistors to the appropriate logic supply level or V

CC

to obtain highest noise

immunity. See figure 11. The resistor R

1

limits the current into the Error indicating pin. This current must not

exceed 8 mA. R

2

is a pull-up resistor which improves noise immunity at the Input. Pull-up current should not

exceed the sinking capacity of the controlling device output.

4. If several supply voltages are to be used, prefer a supply having separate ground leads. In this case the logic

ground and the power ground should be connected together at only one point, the ground pin of the driver.

Switch mode applications

The internal diodes are normally sufficient for clamping of transients caused by inductive load turn off. External

diodes may be necessary in PWM/switch mode applications, and when the terminals are externally accessible and

thereby exposed to an electrically noisy environment. Recommended diodes are BYV27/100, BYV98/100, UF4001

or similar types with a t

rr

< 100 ns and I

F

≥

1 A.

Error indication signal

When the circuit is switched on/off, a short pulse (t

Err

<10

µS

for resistive loads) is generated at the Error output.

This is a correct detection of an incorrect level during the rise and fall times of the output voltage. Consequently the

Error output should not be detected when switching on and off. An alternative is to low-pass filter at the Error output

at around 100 kHz.

Heat sinking

NJM3548TA2 is packaged in a 5-pin TO 220 power package. The circuit GND is connected to the heat sink tab.

External heatsinking is achieved by mounting the package to a heat sink.