ACPM-7886 TD-SCDMA Power Amplifier Data Sheet General Description Features The ACPM-7886 is an amplifier module designed for TD-SCDMA applications in the 2010-2025MHz band. Designed around Avago Technologies’ GaAs Enhancement Mode pHEMT process, the ACPM-7886 offers premium performance in a very small form factor. It is matched to 50 Ohms on the input and output. • • • • • The amplifier has excellent ACLR and efficiency performance at max Pout and low quiescent current (50mA) with a single bias control voltage, Vctrl = 2.0V. Designed in a surface mount RF package, the ACPM7886 is very cost and size competitive. Functional Block Diagram Vdd1 (1) Vdd3 (10) RF in (2) Output Match Bias Control MMIC Module Vctrl (4) Vdd2 (5) Gnd (3,6,7,9) RF out (8) Operating frequency: 2010 - 2025 MHz 28 dBm Linear Output Power @ 3.5V High Efficiency 41% PAE Single bias, low quiescent current (50mA) Internal 50 ohm matching networks for both RF input & output • 3.2 - 4.2 V linear operation • 4.0 x 4.0mm SMT Package • Low package profile, 1.1mm Applications • TD-SCDMA Handsets • TD-SCDMA Data Cards • TD-SCDMA PDAs Package Diagram Vdd3 (Pin 10) AVAGO ACPM-7886 MLYWWDD XXXX Vdd1 (Pin 1) GND RFin RFout N/C (GND) GND Vctrl GND (Pin 6) 4mm sq Vdd2 (Pin 5) Bottom View 1.175mm max Pin Description Table Pin Number Pin Label Description Function 1 Vdd1 Supply bias 1st and 2nd stages drain bias, nominally 3.5V 2 RFin RF input Signal input, internally grounded through inductor. External DC block needed if DC voltage present on input trace. 3 N/C No internal connection Recommend ground connection on PCB 4 Vctrl Control voltage Output level control, nominally 2V 5 Vdd2 Supply bias Bias circuit supply, > 2.5V; nominally 2.85V. Does not require a regulated input and can be connected directly to the battery, if desired. 6 Gnd Ground 7 Gnd Ground 8 RFout RF output 9 Gnd Ground 10 Vdd3 Supply bias 2 Signal output, requires external DC block 3rd stage drain bias, nominally 3.5V Marking Notes : Package Dimensions Row 3: ML = Manufacturing Location Y = Year WW = Work Week DD = Date Code 4.00 ± 0.075mm 0.10mm 2.00mm 0.60mm 0.10mm 0.40mm 3.80mm 4.00 ± 0.075mm 0.45mm 0.60mm Row 4: XXXX = Trace Code (Avago Technologies internal reference) 0.50mm 0.40mm 0.50mm Viewed down through top of package Maximum Ratings Table Parameter Min. Max. Supply voltage, Vdd1 and Vdd3 5.0 V Supply voltage, Vdd2 -1 V 5.0 V Analog control voltage -1 V 3.0 V RF input power +5 dBm Operating case temperature +90 °C Load VSWR 12:1 Storage temperature (case temperature) -30 °C +100 °C Notes: 1. Operation of this device in excess of any of these limits may cause permanent damage. 2. Avoid electrostatic discharge on I/O pins Recommended Operating Conditions Parameter Min. Typ. Max. Supply voltage, Vdd1 and Vdd3 1.0 V 3.5 V 4.5 V Supply voltage, Vdd2 2.6 V 2.85 V 4.5 V Control voltage 1.9 V 2.0 V 2.1 V Case temperature -20 °C 3 +85 °C Electrical Characteristics of TD-SCDMA PA Unless Otherwise Specified: f=2010-2025MHz, Vdd1=Vdd3=3.5V, Vdd2=2.85V, Vctrl=2.0V, Pout=28.0dBm, Ta=25°C, Zin/Zout = 50Ω Parameter Leakage Current, Idd1,2,3; Vctrl=0 V, RF Off min typ 20 Max 80 Units uA Control Current, Ictrl; Vctrl=2.0 V 75 110 145 uA Bias Current, Idd2; Vctrl=2 V, Vdd2=2.85 V 6 10 mA Quiescent Current, Idd1,3; RF Off 50 80 mA 435 480 mA Vctrl=2.0 V At Pout=28.0dBm Supply current Idd1+Idd3 PAE including Vdd1,2,3 36 41 Gain 25.5 28.5 32 dB 1.1 2.0:1 - 1.6MHz offset -40 -35 dBc/1.28MHz 3.2MHz offset -54 -48 dBc/1.28MHz 2nd Harmonic -50 -40 dBc/1MHz 3rd Harmonic -60 -45 dBc/1MHz Noise Figure 3.1 4.1 dB -60 dBc 145 mA Input VSWR % ACLR Stability, no spurious under conditions: VSWR=4:1, all phases 3<Vdd<4.5, -50 dBm to 28.0 dBm At Pout=16dBm Supply current Idd1+Idd3 120 PAE including Vdd1,2,3 9.0 % Gain 28 dB 1.1 - Input VSWR ACLR 1.6MHz offset -42 -35 dBc/1.28MHz 3.2MHz offset -55 -49 dBc/1.28MHz PA Operation/Shutdown Logic: DC signals Vctrl Operational Mode Shutdown 4 2.0V typ < 0.2V Vdd2 2.6 ~ 3.5V ( 2.85V typ) 0 ~ 4.5 V Transmitter Off Power Dynamic Range: 107dB Transmitt Off Power: -83dBm Figure 1. Transmit off power. Signal Studio Configuration Figure 2 TD-SCDMA signal configuration. 5 ESD Sensitivity Level Human Body Model (EIA/JESD22-A114B): Class 1A (250Vmin, less than 500V) Avago Technologies recommends utilizing the standard precautions listed below. Machine Model (EIA/JESD22-A115A): Class A (50Vmin, less than 200V) 1. Calculated Shelf Life in Sealed Bag: 12 months at < 40°C and < 90% Relative Humidity (RH) 2. Peak Package Body Temperature: 250°C 3. After bag is opened, devices that will be subjected to reflow solder of other high temperature process must be: a. Mounted within 168 hours of factory condition ≤ 30°C / 60% RH b. Stored at <10% RH if not used 4. Devices require baking, before mounting if: a. Humidity indicator card is > 10% when read at 23 ± 5°C immediately after moisture barrier bag is opened. b. Items 3a or 3b is not met 5. If baking is required, please refer to J-STD-033 standard for low temperature (40°C) baking requirement in Tape/Reel form. Notes: ESD Sensitivity level for Human Body Model and Machine Model necessitate the following handling precautions: 1. Ensure Faraday cage or conductive shield bag is used during transportation processes. 2. If the static charge at SMT assemble station is above the device sensitivity level, place an ionizer near to the device for charge neutralization purposes. 3. Personal grounding must be worn at all times when handling the devices. Moisture Sensitivity Classification: Class 3 Preconditioning per JESD22-A113-D Class 3 was performed on all devices prior to reliability testing. ACPM-7886 is a moisture sensitive component. It’s important that the parts are handled under precaution and a proper manner. The handling, baking and outof-pack storage conditions of the moisture sensitive components are described in IPC/JEDC S-STD-033A. Tape Dimensions and Orientation 0.30 ± 0.05 4.00 ± 0.10[2] 2.00 ± 0.05[1] 1.75 ± 0.10 ∅1.55 ± 0.05 5.50 ± 0.05[3] CL 4.38 ± 0.10 12.00 ± 0.30 4.38 ± 0.10 ∅1.50 (MIN) 1.80 ± 0.10 8.00 ± 0.10 4.38 ± 0.10 Notes: 1. Measured from centerline of sprocket hole to centerline of pocket 2. Cumulative tolerance of 10 sprocket holes is ± 0.2 mm 3. All dimensions in millimeters unless otherwise stated. Agilent ACPM-7886 MLYWWDD XXXX 6 Reel Dimensions and Orientation BACK VIEW Shading indicates thru slots 18.4 max. 178 +0.4 -0.2 50 min. 25 min wide (ref) Slot for carrier tape insertion for attachment to reel hub (2 places 180° apart) 12.4 +2.0 -0.0 REEL FRONT VIEW CARRIER TAPE USER FEED DIRECTION COVER TAPE Notes: 1. Reel shall be labeled with the following information (as a minimum). a. manufacturers name or symbol b. Avago Technologies part number c. purchase order number d. date code e. quantity of units 2. A certificate of compliance shall be issued and accompany each shipment of product. 3. Reel must not be made with or contain ozone depleting materials. 4. All dimensions in millimeters (mm). 1.5 min. 13.0±0.2 21.0±0.8 Order Information Part Number No. of Devices Container ACPM-7886-BLK 100 Bulk ACPM-7886-TR1 1000 7" Tape and Reel 7 Suggested Board Implementation C5 (10,000pF) C1 (4700pF) C4 (33pF) GND C3 (33pF) C2 (4700pF) Notes: 1. All decoupling capacitors should be placed as close to the power module as possible. 2. RFin (Pin 2) has a grounded inductor inside package as a matching element. An external series capacitor is needed if a DC voltage is present. 3. An additional battery bypass capacitor should be placed on bias line before the battery terminal, but does not need to be immediately adjacent to the PA module. The bypass capacitor should be a large value, nominally between 2.2uF and 4.7uF. 4. Trace impedance on RF lines should be 50Ω. Solder Reflow Profile The most commonly used solder reflow method is accomplished in a belt furnace using convection heat transfer. This profile is designed to ensure reliable finished joints. However, the profile indicated will vary among different solder pastes from different manufacturers and is shown here for reference only. Other factors that can affect the profile include the density and types of components on the board, type of solder used and type of board or substrate material being used. The profile shows the actual temperature that should occur on the surface of a test board at or near the central of the solder joint. For this type of reflow soldering, the circuit board and solder joints are first to get heated up. The components on the Reflow temperature profiles designed for tin/lead alloys will need to be revised accordingly to cater for the melting point of the lead free solder being 34°C (54°F) higher than that of tin/lead eutectic or near-eutectic alloys. In addition, the surface tension of molten lead free solder alloys is significantly higher than the surface tension for tin/lead alloys and this can reduce the spread of lead free solder during reflow. Lead Free Reflow Profile General Guidelines i. Ramp 1 Suggested Lead Free Reflow Profile For SnAgCu Solder Paste Peak = 250 ± 5˚C 250 board are then heated by conduction. The circuit board, because it has a large surface area, absorbs thermal energy efficiently and distributes this heat to the components. Melting point = 218˚C 200 Ramp to 100°C. Maximum slope for this zone is limited to 2°C/sec. Faster heating with ramp higher than 2°C may result in excessive solder balling and slump. ii. Preheat 150 100 50 0 Ramp 2 Preheat Ramp 1 50 150 100 Seconds 8 Cooling Reflow 200 250 Preheat setting should range from 100 to 150°C over a period of 60 to 120 seconds depending on the characteristics of the PCB components and the thermal characteristics of the oven. If possible, do not prolong preheat as it will cause excessive oxidation to occur to the solder powder surface. iii. Ramp 2 2.1 The time in this zone should be kept below 35 seconds to reduce the risk of flux exhaustion. The ramp up rate should be 2°C/sec from 150°C to re-flow at 217°C. It is important that the flux medium retains its activity during this phase to ensure the complete coalescence of the solder particles during re-flow. v. Cooling 0.3 3.9 0.55 0.85 (PITCH) The peak reflow temperature is calculated by adding ~32°C to the melting point of the alloy. Lead free solder paste melts at 218°C and peak reflow temperature is 218°C + 32°C = 250°C (±5°C). Note that total time over 218°C is critical and should typically be 60 – 150 seconds. This period determines the appearance of the solder joints. Excessive time above reflow may cause a dull finish and charred of flux residues. Insufficient time above reflow may lead to poor wetting and improperly fused (cloudy) flux residues. 0.375 0.55 Figure 3. PCB land pattern (dimensions in mm) 1.68 0.64 0.85 iv. Reflow 0.375 0.44 3.12 0.41 Maximum slope for cooling is limited to 3°C/sec. More rapid cooling may cause solder joints crack while cooling at a slower rate will increase the likelihood of a crystalline appearance on the solder joints (dull finish). PCB Design Guidelines The recommended ACPM-7886 PCB land pattern is shown in Figure 3. The substrate is coated with solder mask between the I/O and conductive paddle to protect the gold pads from short circuit that is caused by solder bleeding / bridging. 0.44 0.64 Figure 4. Stencil outline drawing (dimensions in mm) 2.1 Stencil Design Guidelines 9 0.55 0.55 0.44 3.12 3.9 A properly designed solder screen or stencil is required to ensure optimum amount of solder paste is deposited onto the PCB pads. The recommended stencil layout is shown in Figure 4. The stencil has a solder paste deposition opening that is approximately 80% of the PCB pad. Reducing the stencil opening can potentially generate more voids. On the other hand, stencil openings larger than 100% will lead to excessive solder paste smear or bridging across the I/O pads or conductive paddle to adjacent I/O pads. Considering the fact that solder paste thickness will directly affect the quality of the solder joint, a good choice is to use laser cut stencil composed of 0.100mm (4 mils) or 0.127mm (5 mils) thick stainless steel which is capable of producing the required fine stencil outline. The combined PCB and stencil layout is shown in Figure 5. 1.68 Stencil Opening 0.44 Figure 5. Combined PCB and stencil layouts (dimensions in mm) Solder Paste Recommendation Background The ACPM-7886 package is a lead free package that was proven to pass MSL3 when reflowed under lead free solder reflow profile. The recommended lead free solder for SMT reflow is Sn-Ag-Cu (95.5% Tin, 3.8% Silver, 0.7% Copper) or other similar Sn-Ag-Cu solders. This lead free solder paste has a melting point of 218°C (423°F), the ternary eutectic of Sn-Ag-Cu system, giving it the advantage of being the lowest melting lead free alternative. This temperature is still low enough to protect from damaging the internal circuitry during solder reflow operations provided the exposure time at peak reflow temperatures is not too excessive. In 1999 the China Academy of Telecommunications Technology (CATT) and Siemens proposed a new 3G standard that would rival WCDMA and CDMA2000 data rates. Time Domain Synchronous Code Domain Access (TD-SCDMA) combines both CDMA and TDMA technologies. It benefits from CDMA capacity as well as being compatible with current GSM networks. But unlike existing WCDMA, CDMA2000 and GSM networks, this new standard transmits and receives on the same frequency thus greatly increasing spectrum efficiency. Figure 6 simplifies this explanation by showing one TD-SCDMA frame with 7 slots and 16 channelization codes in each slot. In certain situations, the designer may use leaded solder paste for reflow. The recommended solder for mounting ACPM-7886 package is Sn63 (63% Sn, 37% Pb). It is a eutectic compound with a typical melting point of 183°C. Application Information Introduction The ACPM-7886 amplifier module is designed for TDSCDMA applications in the 2010-2025MHz band. This power amplifier is able to produce excellent results for the emerging Chinese standard, TD-SCDMA. Typical ACLR performance at Vdd is 41dBc with Pout of 28dBm and 41% efficiency. Figure 6. TD-SCDMA frame.[1] 10 ACPM-7886 Test Setup The test setup for measuring a TD-SCDMA power module resembles a GSM test. Specifically, it is very important to properly configure the timing for the test instruments and the device under test. In GSM, in order to turn ON and OFF each time slot, a controlled pin on the PA is triggered with a pulse period of 4.615ms and a 12% duty cycle (577uS). This pin is usually labeled as Vapc on most GSM PAs. spectrum analyzer and TSM Signal Studio, all performance tests become much simpler although, ACLR, Gain, PAE, Idd and Spurious emission, etc. can be measured with any spectrum analyzer. TD-SCDMA uses the same control technique except that each frame is 5ms with only 7 timeslots and an additional 75us downlink pilot and a 125us uplink pilot. Each of the 7 slots is 675uS. For the ACPM-7886, the Vctrl pin is used instead of Vapc. As in GSM, there is a time mask specification that must be met, but conformance to this spec is dictated by the Vapc ramp. Figure 7 shows the basic setup used to test ACPM7886 for TD-SCDMA. This includes DC power supply, timing and RF signaling. In brief, the signal generator triggers the pulse generator which in turn triggers the spectrum analyzer and the ACPM-7886 and any other multimeters used. The RF signal is created using Signal Studio on a PC and downloaded to the signal generator via GPIB. In addition to time domain specs, TD-SCDMA must meet linearity requirement. GSM/GMSK is referred to as constant amplitude or constant envelope modulation, and thus the PAM is allowed to operate in saturation. As shown in Figure 6, each time slot supports 16 different CDMA codes with QPSK modulation; as a result this PA must meet similar ACLR specifications as CDMA or WCDMA. Signal Studio [2] facilitates the construction of the complex RF waveform shown in Figure 8. Using this software, one can generate uplink and downlink Dedicated Physical Channel (DPCH) signals along with the uplink and downlink pilot signals. All 7 traffic timeslots are supported, with up to 16 individually configurable code channels per timeslot, for a total of 112 resource units(RU). Signaling Setup To properly test a TD-SCDMA PA module as specified in the TS25.102 standard, one must generate the RF signal shown in Figure 6 along with the timing described in the previous section. Signal Studio for TSM and other standards can be found at: www.agilent.com/find/signalstudio While at the time of publication of this Application note, Agilent Technologies did not have a TD-SCDMA transceiver or a baseband reference module capable of this signal generation, but it does have the E4438C capable of generating a TD-SCDMA waveform. If used in conjunction with Agilent Technologies E4440A 10MHz Out GPIB 10MHz In Event1 Figure 8 displays the main configuration window with only 1 downlink timeslot turned on. Vdd2 Vdd3 Vdd1 RFin RFout 20dB DUT ATTENUATOR Trig In Vctrl ISOLATOR Out Figure 7. TD-SCDMA test setup. 11 Out Trig In Figure 8. Signal Studio configuration. Technically the mobile will transmit on the uplink, but the main point is to display the configurability for each slot. In fact, the test for ACPM-7886 does not require the full 16 code channels. Signal Studio is most beneficial for a base station uplink or downlink test where multiple users will be transmitting on the same time slot. For this test only one time slot is used with a single code. 12 Results In normal CDMA or WCDMA systems, receiver sensitivity is greatly affected by the TX power leakage, thus the transmit off power is of great importance. Figure 9 shows transmit off power of -83dBm which results in 107dBc of dynamic range. 0 2015 MHz ACLR1 -10 2015 MHz ACLR2 -20 ACLR (dB) ACPM-7886 delivers good performance for TD-SCDMA in the 2010 – 2025MHz frequency band see figures 10, 11, and 12. At Vdd of 3.5V, Vdd2 of 2.85 and Vcntl of 2V and Pout of 28dBm this device produces efficiency of 40% and ACLR1/ACLR2 of 41dBc and 56 dBc respectively. -30 -40 -50 -60 -70 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Pout (dBm) Figure 10. ACLR vs. Pout at 2015 MHz. 60 2015 MHz 50 PAE (%) 40 30 20 10 0 0 2 4 6 8 10 12 14 16 18 Pout (dBm) 20 22 24 26 28 30 20 22 24 26 28 30 Figure 11. PAE vs. Pout at 2015 MHz. Figure 9. Transmit Off Power. 29 27 Gain (dB) 25 23 21 19 2015 MHz 17 15 0 2 4 6 8 10 12 14 16 18 Pout (dBm) Figure 12. Gain vs. Pout at 2015 MHz. 13 Summary Avago Technologies ACPM-7886 has demonstrated excellent performance in the emerging Chinese TDSCDMA standard. In addition, ACPM-7886 has a proven track record for great results in the UMTS2100 under WCDMA modulation with or without HSDPA. This makes ACPM-7886 ideal for a dual mode/dual band system for the Chinese market. References [1] TD-SCDMA: The Solution for TDD Band, DiGiuseppe, Principato, Fodor, Siemens White Paper 2002 [2] 29 Oct.-Nov. 2005 http://www.agilent.com/find/ signalstudio. For product information and a complete list of distributors, please go to our web site: www.avagotech.com Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies, Pte. in the United States and other countries. Data subject to change. Copyright © 2006 Avago Technologies Pte. All rights reserved. Obsoletes AV01-0100EN AV01-0319EN - September 1, 2006