CRF-22010-TB 데이터 시트보기 (PDF) - Cree, Inc

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CRF-22010-TB

Evaluation Board for CRF-22010 Version A (Narrowband)

Cree, Inc 

CRF-22010-TB

Handle and test the board in an ESD-protected environment. With all power off, connect the RF and DC cables.

Standard SMA cables will mate to the RF input and output connectors. Connect an external 48 VDC power supply

to the board’s GROUND and DRAIN plugs. The supply should be capable of supplying 1.5 A minimum. Connect

an external adjustable supply to the board’s GROUND and GATE plugs. Observe correct polarity: the GATE

voltage is negative with respect to ground, and the DRAIN voltage is positive with respect to ground. Observe

proper supply sequencing: the negative gate voltage must be turned on before the positive drain voltage.

Adjust the gate voltage so that the CRF-22010 will be operating Class A at VDS = 48 V and IDS ~ 500 mA for initial

checkout.

Connect a 20 dBm, 2.0 GHz source to RF IN and measure output power at RF OUT. The 1 dB gain compression

point should be reached with an input power of 27 dBm to 30 dBm.

Note that, for convenience, the fan uses the board’s 48VDC supply through J4. For monitoring drain current from

the V_DD supply lead, the fan should either be disconnected and supplied separately, or its operating current

should be determined without a transistor installed in the fixture and then subtracted from later measured current

values.

Theory of Operation

Refer to the schematic presented earlier. This circuit is intended only for test and evaluation purposes; it is

not a complete, ready-for-production amplifier.

C1 and C2 are DC blocking capacitors. C11 and the transmission line to which it is connected constitute the input

match. This matching network transforms 50W to the desired source impedance (see the CRF-22010 data sheet).

Likewise C12 and the transmission line to which it is connected transform the desired load impedance to 50W.

These are lowpass matching structures, and they perform impedance matching in the desired band, but they only

give a high-Q, narrowband match. Gate bias is provided through a typical l/4 line; R1 helps to isolate and stabilize

the amplifier. C3 and C4 terminate the line in an RF short, and L1 and C5 provide further supply isolation. Drain

bias is provided through a l/4 line also, but the combination of C8-C10, L2, and the stub in the drain supply line

provide both an RF short and a termination with good video bandwidth. DC is supplied to the test board through

J3, and the fan draws its power through J4.

Some typical swept power and frequency measurements of an evaluation board are presented on the next page.

These data are measured using a typical evaluation board with a typical transistor.

© Cree, Inc. 2003

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Specifications subject to change without notice

http://www.cree.com/

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