TA0012 RFMD | Alldatasheet
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/G01 Copyright 1997-2000 RF Micro Devices, Inc. /G02/G03/G04/G05/G06/G07/G08/G09/G05/G0A/G0B/G04/G03/G0C/G0D/G05/G06/G07/G08/G09/G05/G0E/G0F/G0F/G07/G10/G07/G03/G11/G10/G12/G05/G06/G13/G14/G05/G15/G16/G17/G05/G0A/G0B/G04/G03/G0C/G05/G18/G19/G1A/G1B/G07/G0F/G07/G03/G0C /G01/G02/G03/G04/G05/G06/G07/G04 RF Micro Devices introduces a new power amplifier for GSM applications based on revolutionary HBT (Het- erojunction Bipolar T ransistor) technology. This power amplifier operates from a single 4.8V or 6V power sup- ply without the need for a negative voltage. The power output at 4.8V is 35dBm, and at 6V the P A provides 36dBm! The overall efficiency is as high as 62 percent. On-board power control is included, as is power down. The part is packaged in an industry standard 16-lead SOIC with 4 fused, wide leads. /G08/G09/G04/G05/G0A/G0B/G0C/G07/G04/G0D/G0A/G09 With the maturation of digital cellular systems in Europe, Japan, and North America, next generation handsets must offer advantages to the consumer. These generally take the form of lower cost, smaller size, and longer battery life. One component which has traditionally been either expensive, large, power-hungry, or any combination of these has been the RF power amplifier. This critical component governs much of the battery life, size, ease of implementation, and manufacturability of the phone. For 5-cell applications between 5.3V and 6.0V , this function can now be performed using HBT (Hetero- junction Bipolar T ransistor) technology from RF Micro Devices. The new RF2123 GSM power amplifier pro- vides all of these advantages to the handset designer, amplifying a +6dBm input signal to over +35dBm out- put, at up to 60 percent efficiency. Moreover, no nega- tive voltage is required, either internal or externally generated. Additionally, an on-board analog gain con- trol provides greater than 60dB of power control from 1V to 4V control voltage. When the control is reduced to <0.5V , the part is shut off, drawing less than 1mA. /G0E /G0F/G10 /G01/G0B/G12/G06/G09/G04/G06 /G13/G0F/G03 /G0A/G14 /G15/G16/G17 /G18/G0A/G19/G0F /G05 /G01/G1A/G1B /G1C/G0D/G14 /G0D/G0F/G05 /G17 /G0F/G07/G1D/G09/G0A/G1C/G0A/G13 /G10 The HBT Power Amplifier drives several key features of the phone operation and design. Some are advantages to the end customer, such as talk time and overall phone size. Others are related to the ease of design and manufacturing the phone, such as single voltage supply, on-board power-down, and on-board power control. These advantages are discussed below:
- T alk time. The current consumption of the transmit- ter is dominated by the power amplifier. For battery operated applications, the power-added (or total) efficiency is extremely important. Sixty percent total efficiency for a two-stage, 30dB gain GSM power amplifier IC is ideal for maximizing talk time – a key performance advantage at the competitive system level. Small Package Size. As cellular phone sizes shrink, the available real estate for RF components shrinks as well. T raditional power amplifier designs become difficult to implement in the required area; thus the SOIC packaged, integrated amplifier approach is extremely beneficial. The RF2123 takes the place of a large discrete implementation, or a MESFET IC implementation with additional components such as a negative voltage generator and a supply-side switch. The unique “Quad BatWing” package pio- neered by RF Micro Devices allows superior heat- sinking and electrical grounding. This allows over 4- W of output power to be transmitted in GSM mode with no special heat slug or non-standard packag- ing. No Negative Voltage. HBT is a unique technology, allowing performance better than GaAs MESFETs, yet allowing biasing similar to Silicon Bipolar from a single positive voltage. This eliminates one of the primary disadvantages with GaAs MESFETs – the requirement for a negative voltage. For a system de-signer to implement negative voltage with suffi- cient current to drive a MESFET gate, some kind of switching regulator or “charge pump” must be used. This can be expensive and cumbersome. If the charge pump is implemented on-chip, excessive low-frequency noise, additional leakage current, and additional external components minimize the benefit. HBT provides an elegant solution to the high-effi- ciency power amplifier. With no need for additional components, the part provides an overall smaller, more efficient, and lower cost solution. No supply-side switch. The RF2123 HBT Power Amplifier provides a single pin for power down. This function powers down the part with less than 0.5V on the control pin, and provides full power with 4V on the control. In power-down mode, less than 1mA of total current is consumed, allowing very long stand-by times for the phone. TA0012 T A0012 RF2123: New High Power, High Efficiency HBT GSM Power Amplifier /G1C/G1D
Copyright 1997-2000 RF Micro Devices, Inc. stantial portion of the overall power amplifier cost. characteristic is shown in Figure 1. peratures of 250°C are used to accelerate the test. nally developed for military and space applications. Figure 1. Output power vs. Vpc from 0 to 4V . Note that the power control range is >60dB with the maximum output power at 36.3dBm.
Copyright 1997-2000 RF Micro Devices, Inc. geometries typically required by GaAs MESFETs. ucts to determine the ruggedness and failure rates. supplier of GaAs HBT circuits.
- The part is a two-stage device with 30dB gain at full
through the large pins on both sides of the package. Figure 2. Block Diagram and Pinout for RF2123.
Copyright 1997-2000 RF Micro Devices, Inc. thus, a blocking cap must be inserted in series. as provides some control over the operating band. lize and dequeue the circuit. capable of supporting the 1-1.5A of current required. the supply voltage, forcing the device into breakdown. a rugged, robust component for the system designer. taken with a 12.5% duty cycle and a 600ms pulse. well as significantly reducing overall cost. Table 1. RF2123 Performance Summary