BD544A Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -60 V
• Collector-Base Voltage, max: -60 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -8 A
• Collector Dissipation: 70 W
• DC Current Gain (h_fe): 60
• Operating and Storage Junction Temperature Range: -65 to +150 °C
• Package: TO-220

Here is an image showing the pin diagram of this transistor.The complementary NPN transistor to the BD544A is the BD543A.The STN951 (SOT-223) is the SMD version of the BD544A transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the BD544A with the 2N6040, 2N6040G, 2N6041, 2N6041G, 2N6042, 2N6042G, 2N6667, 2N6667G, 2N6668, 2N6668G, 2SA1077, 2SA1291, 2SA1291-Q, 2SA1291-R, 2SA1291-S, 2SA1329, 2SA1329-O, 2SA1329-Y, 2SA1452, 2SA1452-O, 2SA1452-Y, 2SA1452A, 2SA1452A-O, 2SA1452A-Y, 2SA1471, 2SA1471-Q, 2SA1471-R, 2SA1471-S, 2SA1743, 2SA1743-K, 2SA1743-L, 2SA1743-M, 2SA1744, 2SA1744-K, 2SA1744-L, 2SA1744-M, 2SB1225, 2SB1228, 2SB882, 2SB886, 2SB951, 2SB951-P, 2SB951-Q, 2SB951A, 2SB951A-P, 2SB951A-Q, BD544B, BD544C, BD546A, BD546B, BD546C, BD646, BD648, BD650, BD652, BD898, BD898A, BD900, BD900A, BD902, BDT62, BDT62A, BDT62B, BDT62C, BDT64, BDT64A, BDT64B, BDT64C, BDW45, BDW46, BDW46G, BDW47, BDW47G, BDW48, BDW74A, BDW74B, BDW74C, BDW74D, BDW94A, BDW94B, BDW94C, BDW94CF, BDX34A, BDX34B, BDX34BG, BDX34C, BDX34CG, BDX34D, BDX54A, BDX54B, BDX54BG, BDX54C, BDX54CG, BDX54D, D45H11, D45H11FP, D45H8, MJF6668, MJF6668G, TIP105, TIP105G, TIP106, TIP106G, TIP107, TIP107G, TIP135, TIP135G, TIP136, TIP136G, TIP137, TIP137G, TIP145T, TIP146T, TIP147T, TTA1452B or TTB1452B.