The HFA3101 is an all NPN transistor array configured as a multiplying cell. In the UHF-1soi process based on Intersil bonded wafers, the array achieves very high fT (10 GHz), while

Maintaining good hFE and VBE matching characteristics Make this product a communication circuit by carefully paying attention to circuit maximization design and layout. The battery provides high gain and good second-order anti-distortion terms when used in mixer applications.

Note: Intersil lead-free products feature a special set of lead-free materials; molding compound/die attach material and 100% matte tin with SnPb and lead-free soldering operations. Intersil's lead-free products are MSL's lead-free requirements classified as IPC/JEDEC J STD-020C when meeting or exceeding the lead-free peak reflow temperature.

feature

Pb-free high-gain bandwidth products (fT) are available as options. 10 Hz high power gain bandwidth product. 5 Hz current gain (hFE). 70 low noise figure (transistors). Excellent hFE and VBE matching of 3.5dB for low collector leakage current. <0.01 mA pin-to-pin compatible with UPA101

application

Balance mixer

multiplier

Demodulator/Modulator

Automatic gain control circuit

Phase detector

Fiber Signal Processing

wireless communication system

Broadband amplifier stage

radio and satellite communications

high performance instrument

Absolute Maximum Ratings Thermal Information

VCEO, collector-emitter voltage. 8.0V

VCBO, collector-to-base voltage. 12.0V

VEBO, Emitter-to-Base Voltage. 5.5V

IC, collector current. 30 mA operating condition temperature range. -40oC to 85oC Thermal Resistance (Typical, Note 1) θJA(oC/W) SOIC Package. 185

Maximum junction temperature (die) 175 degrees Celsius

Maximum Junction Temperature (Plastic Package)…150°C

Maximum storage temperature range...-65°C to 150°C

Maximum lead temperature (soldering for 10s)...300 degrees Celsius (SOIC - lead only)

Note:

1. θJA is measured in free air with components mounted on the evaluation PC board

Electrical specification TA=25oC

Note:

2. Test levels: A. Production tested, B. Typical or guaranteed limits based on characteristics, C. Typical design for reference only.

application information

The HFA3101 array is a very versatile RF building block. It has been carefully laid out to improve its matching properties with minimal distortion due to area mismatch, thermal distribution, beta and ohmic resistance. This unit acts as a two differential stage "variable transconductance multiplier" cross-coupled with the output. This configuration acts as an industrial multiplication of Gilbert cells. The use of the HFA3101 battery as a linear four-quadrant is limited due to the dynamic range of the input limiting the levels of the upper and lower tailpipes. However, its configuration is ideal for use when its linear response is limited to one of the inputs, such as in modulator or mixer circuits. Examples of these circuits are upconverters, downconverters, frequency doublers, and frequency/phase detectors.

Although linearization is still a low-to-input problem, emitter degradation can be used to improve dynamic range and subsequent linearity. For this of the HFA3101, connect the two transmitters to external pins. In modulator applications, the upper four transistors are used in switch mode, where Q1/Q2 and Q3/Q4 act as non-saturating high-speed switches. These switches are controlled by a signal commonly called a carrier input. The signal that drives the next pair of Q5/Q6 is usually used as the modulation input. This signal can be linear by using a low signal level to the output (well below the 26mV thermal voltage) or emitter degradation. The chopping waveform appears at the output of the upper pair (Q1 to Q4) similar to a signal multiplied by a +1 or -1 switching waveform every half cycle.

The figure shows a typical input waveform where the carrier frequency is higher than the modulating signal. The output waveform shows the output of a typical suppressed carrier upconverter or AM signal generator. The carrier suppression capability is known as a balanced modulator, which returns to zero when one or the other input (carrier or modulating signal) is equal. However, at very high frequencies, high frequency mismatches and AC offsets are always present, and rejection is often reduced, resulting in carrier and modulation feedthrough. As a frequency conversion circuit, the balanced modulator has the characteristic of converting the modulation frequency (ωM) to the carrier frequency (ωC), resulting in two side bands ωU=ωC+ωM and ωL=ωC-ωM. Figure shows some conversion schemes used by balanced mixers.

Using the HFA3101 as a modulator has several advantages of the diode compared to similar products. Double-balanced mixers require receiving enough energy to drive the diode into switching mode. There are also some requirements depending on the frequency. frequency response. The drive capability response of the HFA3101 requiring a very low carrier input and frequency is affected by the fT of the device, the design and the layout technique being used. Upconversion is used, for example, for UHF transmitters, by using baseband at 45MHz to 130MHz, carrying information commonly called IF (intermediate frequency) for upconversion (the intermediate frequency signal has been modulated by some modulation scheme before audio or digital information signal) and into the carrier input by injecting a LO signal with a much wider frequency range from 600MHz to 1.2GHz. An example spectrum using 850MHz carrier input and 70MHz IF output would contain a 920MHz upper sideband, a lower 780MHz sideband and partial carrier (850MHz) and IF (70MHz) feedthrough. A bandpass filter at the output attenuates bad signals, and the 920MHz signal can be connected to a transmitter RF power amplifier. As the name implies, down-conversion is the use of a range of high-frequency signals that converts a high-frequency signal into a low-frequency signal to preserve modulation information. A very common example is used in superheterodyne radios to convert signals received at lower frequencies to intermediate frequency (IF) for detection or demodulation of baseband signals. Other application uses include downconversion methods using frequency for special filtering.

An oscillator called the Local Oscillator (LO) drives an RF signal at frequency ωC. The lower pair is driven by an RF signal of frequency ωM to convert to a lower frequency IF. The spectral IF output will contain frequencies ωC and ωM. Note that when the LO frequency is lower than the input frequency, the signal is folded as shown. Note: The acronyms RF, IF and LO are used depending on the battery as a mixer or regulator. The output of the cell also contains the frequency of the signal fed to the upper four pairs of transistors because the switching action is equivalent to square wave multiplication. In practice, however, not only the case of symmetrical square waves, but some even multiples also appear in the output spectrum due to the actual nature of switching waveforms and high frequency performance. A by-product of the form M*ωC+N*ωM, where M and N are positive or negative integers, also appear at the output and their levels are scrutinized and minimized by design. This twist is considered one of the advantages of mixer applications.

The process of frequency doubling can also be understood as having the same signal being transmitted to both the modulation and carrier ports. The output frequency is ωC and ωM is equal to the product of the input frequency of 2, the zero Hz or DC frequency is equal to the difference between ωC and ωM. Figure 2 also shows that in the technique used today, the down-conversion process is named zero if it is modulated with a signal (audio or digital) containing baseband with a pure signal frequency equal to the input RF frequency. Despite the complexity, extracting or detecting the signal is straightforward. Another useful application for the HFA3101 is a frequency phase detector, feeding two signals to the carrier and modulation ports and extracting the DC information from the output. In this case, both ports are switching modes or overdriving, making the multiplication in quasi-digital form (2 squared waves). One application of a phase detector is frequency or phase demodulation, where the FM signal is at the modulation and carrier ports. The lower input port is always 90 and the phase shift network is tuned by the distance of the high Q from the carrier input signal. The network, which is moving exactly 90 degrees at the nominal frequency, will set the two signals 90 degrees apart and the static output DC level will appear at the output. When the input signal is frequency modulated, the frequency deviation from the network will deviate from the FM signal and the output will occur, similar to a demodulated FM signal. The HFA3101 can also be used for quadrature detection, (I/Q demodulation), limited range AGC control, low level multiplication to name a few other applications.

bias

Various biasing schemes are available for the HFA3101. The figure shows the most common scenarios. This biasing method is a designer's choice when it comes to cost, properties that take into account thermal dependencies, voltage overhead, and DC balance. Figure A shows the simplest form of biasing the HFA3101. The lower pair of the required current source reduces the transistor by subtracting the voltage across the resistor RBIAS. To add overhead, the collector resistor is replaced by an RF choke as the upper pair functions as a current source for the AC signal. The upper and bottom lower transistors are biased by RB1 and RB2 respectively. The voltage drop across resistor R2 must be higher than VBE by an amount sufficient to ensure that the collector-to-substrate connection of the next pair is always reverse biased. It is important to note the VCE for operation at the same voltage setting in order to optimize the gain. Resistor REE is nominally 25 mV peak for applications where the input signal is well below zero. Resistor REE is used to increase the linearity of the circuit for high-level signals. The source value must be considered when setting the current. Panel B depicts the use of a shared resistor through the battery for temperature compensation of -2 mV/degree Celsius when VBE drops under current. Figure C using a shunt power supply

Design Example: Downconverter Mixer

Figure shows an example application of a low-cost cellular mixer

The design flexibility of the HFA3101 is demonstrated by A. 900MHz low cost, low voltage mixer application range. Selection of high-quality chip components is important for self-resonance outside the application boundaries. The design is optimized to accommodate the evaluation current values and lower supply voltages of the same layout at different quiescent states. Then select for the available overhead and maintain a high frequency AC true impedance signal. A value of 27Ω is the minimum value for optimal value applications. The input impedance of the HFA3101 basic input port is high enough to terminate with a 50Ω resistor. Signal AC termination by decoupling the bias circuit with a high quality capacitor. Biased selection of supply voltage with R1, R2 and RBIAS values divides the voltage to obtain the best VCE value. For evaluation In battery quiescent current, the voltage at the emitter has recorded resistance RE. The gain of the circuit, which is the combined resistance of the load and the high frequency emitter, is kept to a maximum value by using an output matching network. The high output impedance of the HFA3101 allows broadband matching, if required, at 50Ω (RL = 50Ω to 2kΩ) as well as tuning the dielectric Q matching network (L, T, etc.).

stability

Cells, by their nature, have high gain and precautions must take into account the combined signal reflection, gain, layout and package parasitics. Rules must take care to avoid reflected waves. It is important to ensure a good match between the mixer stage and its front end. Lab measurements show vibration-sensitive transistor inputs on the upper quad. Any LO pre-filtering must be designed such that the gain loss remains within acceptable limits especially at high frequencies. A typical off-the-shelf filter shows the signal in the passband. A "pad" or broadband resistor network is recommended for connecting the LO port with filtering. Including a parallel 2K resistor in the load slightly reduces gain, improves stability and improves distortion products (output intermodulation or third-order intercept). Hiring a good RF technology should meet stability requirements.

Upconverter example

Upconverters and converter applications can use the same layout to demonstrate multipliers to add matching components. The output port S22 must have a proper matching procedure and according to the frequency required for the output, the transmission line transformation can be designed. The return loss of this input port is in excess of 1.2GHz, allowing the evaluation of a frequency multiplier to 2.4GHz if required. The addition of resistor REE can greatly increase the dynamic range of the upconverter as shown in the figure. The evaluation results shown in Table 5 were obtained from three stub tuners as matching networks due to placement constraints. Based on the evaluation results it is clear that the cells require higher bias currents for overall performance.