LM9036

Unlike other PNP low dropout regulators, the LM9036 remains fully operational to 40V. Owing to power dissipation characteristics of the package, full output current cannot be guaranteed for all combinations of ambient temperature and input voltage.

The junction to ambient thermal resistance _JA rating has two distinct components: the junction to case thermal resistance rating _JC; and the case to ambient thermal resistance rating _CA. The relationship is defined as: _JA = _JC + _CA. On the TO-252 package the ground tab is thermally connected to the backside of the die. Adding 1 square inch of 2 oz. copper pad area directly under the ground tab will improve the JA rating to approximately 50°C/W. While the LM9036 has an internally set thermal shutdown point of typically 150°C, this is intended as a safety feature only. Continuous operation near the thermal shutdown temperature should be avoided as it may have a negative affect on the life of the device. Using the _JA for a LM9036DT mounted on a circuit board as defined at (Note 8), and using the formula for maximum allowable dissipation given in (Note 3) for an ambient temperature (T_A) of +85°C, we find that P_DMAX = 1.3W. Including the small contribution of the quiescent current I_Q to the total power dissipation, the maximum input voltage (while still delivering 50mA output current) is 29.5V.

The LM9036DT will go into thermal shutdown when attempting to deliver the full output current of 50mA, with an ambient temperature of +85°C, and the input voltage is greater than 29.5V. Similarly, with an ambient temperature of 25°C the P_DMAX = 2.5W, and the LM9036DT can deliver the full output current of 50mA with an input voltage of up to 40V. While the LM9036 maintains regulation to 55V, it will not withstand a short circuit above 40V because of safe operating area limitations in the internal PNP pass device. Above 55V the LM9036 will break down with catastrophic effects on the regulator and possibly the load as well. Do not use this device in a design where the input operating voltage may exceed 40V, or where transients are likely to exceed 55V.

The LM9036 ultra-low quiescent current regulator features low dropout voltage and low current in the standby mode. With less than 25µA Ground Pin current at a 0.1mA load, the LM9036 is ideally suited for automotive and other battery operated systems.

The LM9036 retains all of the features that are common to low dropout regulators including a low dropout PNP pass device, short circuit protection, reverse battery protection, and thermal shutdown.

The LM9036 has a 40V maximum operating voltage limit, a −40°C to +125°C operating temperature range, and ±5% output voltage tolerance over the entire output current, input voltage, and temperature range.