Power Bipolar Transistor
For High Frequency Ballasts

BUL742A Product Page
BUL742C Product Page

The typical 277V ac push-pull configuration shows the reduction in components required when using the BUL742 solution - a saving of up to ten components.

To reinforce ST’s leadership as a manufacturer of power Bipolar Transistors and to respond to the continuous market demand, ST is enlarging its already wide lighting product range, with the introduction of the BUL742 for High Frequency ballast applications.

Features

	Minimum lot-to-lot spread;
	High voltage capability (Bvces>900V);
	Fast switching time;
	Avalanche proof (6mJ with a L=2mH) ;
	Available in a wide package range: TO-220, I²PAK (BULB742-1) and D²PAK (BULB742T4)

The BUL742 bipolar is manufactured using high voltage multiepitaxial planar technology for high switching speeds and high voltage capability. It uses a cellular emitter structure with planar edge termination to enhance switching speeds while maintaining the wide RBSOA. Thanks to an increased intermediate layer, the device has an intrinsic ruggedness which enables the transistor to withstand a high collector current level during breakdown condition without using the transil protection usually necessary in typical converters for lamp ballast.

A selection of Bipolar High Frequency Ballast

Device	VCEO (V)	VCES (V)	IC (A)	Package	Push pull (220V AC mains)	Half bridge (220V AC mains)
BULK128D/-B	400	700	4	SOT-82	-	up to 40 W
BUL128	400	700	4	TO-220	-	up to 40 W
BUL128D/-B	400	700	4	TO-220	-	up to 40 W
ST13005	400	700	4	TO-220	-	up to 40 W
ST13007	400	700	8	TO-220	up to 140 W*	up to 140 W
BUL138	400	800	5	TO-220	up to 80 W*	up to 80 W
BUL381D/2D	400	800	5	TO-220	up to 80 W*	up to 80 W
BUL742	400	900	4	TO-220	up to 120 W*	up to 120 W#
BUL903ED	400	900	5	TO-220	up to 130 W*	up to 130 W#
BUL310	500	1000	5	TO-220	-	up to 120 W
BUL1203E	550	1200	5	TO-220	-	up to 120 W#
BUL213	600	1300	3	TO-220	up to 90 W	up to 90 W#
BUL1403ED	650	1400	3	TO-220	up to 130 W#	-
suffix D = integrated free-wheeling diode *120V ac mains #277V ac mains

Benefits

The BUL742 thanks to its intrinsic ruggedness, offers a good trade-off in terms of performance and cost, making this technology very flexible and ideal for cost effective lighting solutions. The BUL742 is a 900V breakdown voltage device, so it is suggested for electronic lamp ballast 2/4 x 32W lamps using 120V push-pull configuration and for ballast 4 x 32W lamps using 277V half bridge current-fed configuration. In the typical 120Vac push-pull configuration shown below the 2 TRANSILS can be eliminated when the BUL742 solution is chosen. The BUL742 is housed in the most common industry standard through-hole and SMD packages, making this bipolar transistor flexible for any PCB assembly solution.