SLASE37A May 2014 – December 2014 TRF37A32 , TRF37B32 , TRF37C32
PRODUCTION DATA.
NOTE
Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.
The devices are high-linearity, wideband receive mixers. They are typically implemented to convert frequencies from the range 400 MHz to 3800 MHz into the range 30 MHz to 600 MHz.
The TRF37x32 device is typically placed in a system as illustrated in Figure 75.
A typical schematic for the TRF37x32 is shown in Figure 76.
For this design example, use the parameters shown in Table 3.
MIXER PARAMETER | EXAMPLE APPLICATION REQUIREMENTS(1) | TRF37B32 PERFORMANCE (TYPICAL) |
---|---|---|
RF Frequency Range | 2300 - 2400 MHz | 700 - 2700 MHz |
IF Frequency Range | 318.64 - 418.64 MHz | 30 - 600 MHz |
Gain | 9 - 10 dB | 9.7 dB at FRF = 2300 MHz |
NF | < 12 dB | 10 dB at FRF = 2300 MHz |
IIP3 | > 28 dBm | 30 dBm at FRF = 2300 MHz |
IP1dB | > 8 dBm | 11 dBm at FRF = 2300 MHz |
Input power should back off from the TRF37x32 compression point for linear operation, ideally by 10dB or more. Choose LNA gain and gain scheduling in order to set the appropriate power level at the RF input to the TRF37x32.
Given the expected input power level, use the expected gain through the mixer and other elements, such as SAW filter and matching networks, to calculate the voltage expected at the ADC. Adjust gain and loss elements to maximize the utilization of ADC dynamic range.
Although the TRF37x32 was designed to interface with 50 Ω RF and LO and 200 Ω differential signal lines, some elements in the signal chain may not present a wideband real impedance. Matching components are optional but may be used at these ports to improve impedance alignment, thereby increasing power delivered to the RF node and decreasing reflected and radiated power. Good matching maximizes isolation and linearity performance.
The blocking capacitor value on the RF input should be selected according to Table 1.
Use high Q inductors for pull-up biasing on the IF output. 270 nH 0805-size wirewound indictors provides excellent linearity and gain. Larger inductor values may compress the IF bandwidth, while smaller package sizes tend to introduce lower inductor Q ratings.
Connect the supply nodes of both inductors for a given channel symmetrically to the VCC net with close proximity to ensure balanced connection to the supply.
The LO and RF inputs are both designed for wideband behavior, and either high-side or low-side injection may be used interchangeably across most of the RF band. At the extreme RF frequencies the LO input bandwidth will force operation to either high side injection (HSI) or low side injection (LSI). Table 2 provides the operating range of the LO for each device. Where possible it is recommended to utilize low side injection to keep the power dissipation to a minimum.
Decoupling capacitors reduce terminal noise but also slow transient response. Adjust external capacitors in order to meet specified power-on and power-off response times. Apply transmission line matching techniques to achieve the fastest response times.