LM12

The LM12 is a power op amp capable of driving ±25V at ±10A while operating from ±30V supplies.The monolithic IC can deliver 80W of sine wave power into a 4 load with 0.01% distortion. Power bandwidth is 60 kHz. Further, a peak dissipation capability of 800W allows it to handle reactive loads such as transducers, actuators or small motors without derating.Power op amps introduce new factors into the design equation.With current transients above 10A, both the inductance and resistance of wire interconnects become important in a number of ways. Further, power ratings are a crucial factor in determining performance. But the power capability of the IC cannot be realized unless it is properly mounted to an adequate heat sink. Thus, thermal design is of major importance with power op amps.

Features of the LM12 are:(1)input protection;(2)controlled turn on;(3)thermal limiting;(4)overvoltage shutdown;(5)output-current limiting;(6)dynamic safe-area protection.The IC delivers ±10A output current at any output voltage yet is completely protected against overloads, including shorts to the supplies.The dynamic safe-area protection is provided by instantaneous peak-temperature limiting within the power transistor array.The LM12 establishes that monolithic ICs can deliver considerable output power without resorting to complex switching schemes. Devices can be paralleled or bridged for even greater output capability. Applications include operational power supplies, high-voltage regulators, high-quality audio amplifiers, tape-head positioners, x-y plotters or other servo-control systems.

The absolute maximum ratings of the LM12 can be summarized as:(1)lead temperature(soldering,10 second):300°C;(2)storage temperature range: -65 to +150°C;(3)total supply voltage:80V;(4)output current:internally limited.The availability of a monolithic power op amp now promises to extend these advantages to high-power designs. Some conventional applications are given here to illustrate op amp design principles as they relate to power circuitry. The inevitable fall in prices, as the economies of volume production are realized, will prompt their use in applications that might now seem trivial. Replacing single power transistors with an op amp will become economical because of improved performance,simplification of attendant circuitry, vastly improved fault protection, greater reliability and the reduction of design time.