RF3865TR7 RFMD, RF3865TR7 Datasheet - Page 9

• Manufacturer Part Number: RF3865TR7
• Description: IC AMP LOW-NOISE 2-STAGE 20-QFN
• Manufacturer: RFMD

Specifications of RF3865TR7

• Current - Supply: 170mA
• Frequency: 700MHz ~ 3.8GHz
• Gain: 20dB
• Noise Figure: 1.1dB
• P1db: 22dBm
• Package / Case: 20-QFN
• Rf Type: Cellular, CDMA, PCS, DCS, UMTS, WLAN, 802.16/WiMax
• Test Frequency: 3.3GHz ~3.8GHz
• Voltage - Supply: 2.5V ~ 6V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Low noise figure and high gain/IP3 make the RF3865 ideal for use as both receive LNA and transmit driver for cellu-
lar/DCS/PCS/UMTS and WiMax platforms, in addition to many other general purpose applications. Standard evaluation boards
cover 700MHz to 1100MHz and 800MHz to 3800MHz. Viewing the data sheet evaluation board schematic, refer below for
the purpose/function of external components.
• R2/L4/C6 (0Ω/unpopulated/unpopulated on standard evaluation boards); These unused components were placed for
• L3/C5/C7: Placed to optimize input match and enhance out of band low frequency stability.
• R3: Optionally placed to increase bias current and IP3. 20Ω value is found to be the best case. Refer to RF3861, RF3863,
• L1/C3/R5/C8: Interstage tuning.
• L2/C4: Influence output return loss.
RF3865 has internal DC-blocking capacitors at RFin and RFout. In addition, it has been shown impedance seen looking out at
pins 7/9/17/19 influence response. As a result, two port s-parameters become non-applicable. If matching is desired for fre-
quency bands outside of those provided with standard evaluation boards, an application schematic within this data sheet for
550MHz to 3000MHz serves as an example. In the 550MHz to 3000MHz application, design goals were as follows:
• Input and output return loss equal to or better than 10dB over the entire 2450MHz bandwidth.
• IP3 and compression point in line with standard evaluation board performance.
These goals were attained, with additional specifications shown in the graph section of the data sheet:
• Noise figure<=1.2dB from 1000MHz to 2500MHz
• Gain>30dB from 550MHz to 2000MHz
The above matching discussion should be helpful when considering use in frequency bands outside of those covered by stan-
dard evaluation boards. It can be noted here that application schematics and standard boards collectively cover 87% of the
usable bandwidth from 400MHz to 3800MHz. As such, choosing from these available schematics should accommodate the
majority of applications that come about.
DS100113
convenience and flexibility when needed to optimize matching for an out of band application.
and RF3866 data sheets for graphical demonstration of 20Ω optimal value. RF3865 has been confirmed to follow the
same trend.
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Theory of Operation
RF3865
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