START540TR STMicroelectronics, START540TR Datasheet - Page 2

• Manufacturer Part Number: START540TR
• Description: RF Bipolar Small Signal NPN High Frequency
• Manufacturer: STMicroelectronics

Specifications of START540TR

• Dc Collector/base Gain Hfe Min: 100
• Mounting Style: SMD/SMT
• Configuration: Single
• Transistor Polarity: NPN
• Collector- Emitter Voltage Vceo Max: 4.5 V
• Emitter- Base Voltage Vebo: 1.5 V
• Continuous Collector Current: 0.04 A
• Power Dissipation: 180 mW
• Maximum Operating Temperature: + 150 C
• Package / Case: SOT-323-4
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AN1465 - APPLICATION NOTE
A single pin (V
=3V) for voltage supply is used. A 1µF bypass capacitor to filter the supply at the common
cc
V
node is also used. The transistor's base is connected to the power supply through a choke inductor
cc
(L2) and the transistor's collector is connected to the power supply through a choke inductor (L3). The
collector's voltage is 2V. The input matching is realized with a 50ohm series transmission line.The L2
inductor is used to reduce the Noise Figure value The output matching is realized with a 50ohm series
transmission line and inductor (L3). Resistor (R3) is used to improve RF circuit stability.Low frequency
decoupling capacitors C4 (47nF) for the base and C6 (47nF) for the collector improve the IP3
considerably. It's possible, removing R4, to supply separately the collector and the base using a different
voltage supply. In this way, it's possible to set a different value of current in the collector (Icc).
3. DEMOBOARD Specification.
Figure 2 is the PC board cross section. The board material is standard FR4. Note that spacing from the
top layer RF traces to the internal ground plane is 0.010 inch (0.254 mm). The width of 50ohm microstrip
is 0.45 mm.
Figure 2: Cross-section of pcb board
Figure 3: Image of the START540 DEMOBOARD (Size 22x30 mm)
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