βM337

The βM337 series are adjustable 3-terminal negative voltage regulators made by IPRS Băneasa [1].

The I.P.R.S. Băneasa Full Line Condensed Catalog (1990) lists the βM337H and βM337AH (TO-39 package) [1], the βM337K and βM337AK (TO-3) [2] and the βM337T and βM337AT (TO-220) [3], all marked as preliminary data. They are adjustable 3-terminal negative regulators that supply in excess of −1.5 A over a −1.2…−37 V output range, needing only two external resistors to set the output voltage and one output capacitor for frequency compensation; the circuit has full overload protection (current limit, thermal protection and safe operating 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 is the complement of the βM317 adjustable positive regulators [1]. The description on the TO-220 page also begins „The βM 337H is…” [3].

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 0.3 % (TO-39 and TO-220) or 0.1 % (TO-3) and a maximum input–output differential of −40 V for the βM337H/K/T and −25 V for the βM337AH/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 in all three packages: 1 adjustment, 2 output, 3 input, the case being the input [1][2][3].

The typical applications in the catalog are in the Gallery: an adjustable lab voltage regulator (with a βM317 for the positive side) and a −5.2 V regulator with electronic shutdown [1]; an adjustable negative regulator with protection diodes, with −VOUT = −1.25 V·(1 + R2/R1) − R2·Iadj (Iadj typ. 65 µA), and an adjustable current regulator, with IOUT = 1.5 V/R1 ± 15 % [2]; a current regulator, with IOUT = 1.25 V/R1 (0.8 Ω < R1 < 120 Ω), and digitally selected outputs [3].