βM317

The βM317 series are adjustable 3-terminal positive voltage regulators made by IPRS Băneasa [1].

The I.P.R.S. Băneasa Full Line Condensed Catalog (1990) lists the βM317H and βM317AH (TO-39 package) [1], the βM317K and βM317AK (TO-3) [2] and the βM317T and βM317AT (TO-220) [3], all marked as preliminary data. They are adjustable 3-terminal positive regulators that supply more than 0.5 A (βM317H) or more than 1.5 A (βM317K, βM317T) over a 1.2…37 V output range, needing only two external resistors to set the output voltage; the circuit has full overload protection (current limit, thermal protection and safe area protection), and the rated power dissipation is about 2 W in TO-39, 20 W in TO-3 and 15 W in TO-220 [1][2][3]. The series is meant for local on-card regulation, programmable-output voltage regulation or precision current regulation, and also makes a simple adjustable switching regulator; since the regulator is „floating”, supplies of more than 37 V are possible as long as the maximum input–output differential is not exceeded [1].

The catalog gives an operating junction temperature range of 0…+125 °C, a typical line regulation of 0.01 %/V, a typical load regulation of 0.1 % and a maximum input–output differential of 40 V for the βM317H/K/T and 25 V for the βM317AH/AK/AT; the junction-to-case thermal resistance, without a heat sink, is at most 15 °C/W in TO-39, 3 °C/W in TO-3 and 4 °C/W in TO-220 [1][2][3]. Pins: TO-39 (bottom view) 1 input, 2 adjustment, 3 output [1]; TO-3 (bottom view) and TO-220 (front view) 1 adjustment, 2 input, 3 output [2][3]; in all three packages the case is the output [1][2][3].

The typical applications in the catalog are in the Gallery: a high current adjustable regulator and a 50 mA constant current battery charger [1]; an adjustable 4 A regulator (three βM317 with a βM308 operational amplifier) and an adjustable positive regulator with protection diodes [2]; several on-card regulators adjusted with a single control, and a current limited 6 V charger [3].