DATA SHEET SKY77321 PA Module for Tri-Band EGSM / GPRS Applications Description • Tri-band cellular handsets encompassing - Class 4 EGSM900 - Class 1 DCS1800 - PCS1900 - GPRS (up to Class 12) The SKY77321 Power Amplifier Module (PAM) is designed in a compact form factor for tri-band cellular handsets comprising EGSM900, DCS1800, and PCS1900 operation. It also supports Class 12 General Packet Radio Service (GPRS) multislot operation. Features • High efficiency - EGSM900 53% - DCS1800 47% PCS1900 47% • Input/output matching 50 Ω internal • Small outline 6 mm x 6 mm • Low profile 1.2 mm maximum • Low APC current 10 µA typical • Gold plated, lead-free contacts The PAM consists of an EGSM900 PA block, a DCS1800/PCS1900 PA block, impedance-matching circuitry for 50 Ω input and output, and bias control circuitry. Two separate Heterojunction Bipolar Transistor (HBT) PA blocks are fabricated on a single Gallium Arsenide (GaAs) die. One PA block operates in the EGSM900 band and the other PA block supports both the DCS1800 and the PCS1900 bands. Optimized for Li-Ion battery operation, both PA blocks share common power supply pins to distribute current. A custom CMOS integrated circuit provides the internal interface circuitry, including a current amplifier that minimizes the required power control current (IAPC) to 10 µA, typical. The GaAs die, the Silicon (Si) die, and passive comments are mounted on a multi-layer laminate substrate. The assembly is encapsulated with plastic overmold. The RF input and output ports are internally matched to 50 Ω to reduce the number of external components for a tri-band design. Extremely low leakage current (2 µA, typical) of the dual PA module maximizes handset standby time. The SKY77321 also contains band-select switching circuitry to select EGSM (logic 0) and DCS/PCS (logic 1) as determined from the Band Select (BS) signal. In the block diagram shown below, the BS pin selects the PA output (DCS/PCS OUT or EGSM OUT) while the Analog Power Control (APC) controls the level of output power. Skyworks offers lead (Pb)-free "environmentally friendly" packaging that is RoHS compliant (European Parliament for the Restriction of Hazardous Substances). Figure 1. Functional Block Diagram Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 103030B • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • September 9, 2005 1 DATA SHEET • SKY77321 PA MODULE FOR TRI-BAND EGSM / GPRS Electrical Specifications The following tables list the electrical characteristics of the SKY77321 Power Amplifier Module. Table 1 lists the absolute maximum ratings and Table 2 lists the recommended operating conditions. Table 3 shows the electrical characteristics of the SKY77321 for EGSM, DCS, and PCS bands. A typical SKY77321 application diagram appears in Figure 2. The SKY77321 is a static-sensitive electronic device and should not be stored or operated near strong electrostatic fields. Detailed ESD precautions along with information on device dimensions, pin descriptions, packaging and handling can be found in later sections of this data sheet. Table 1. Absolute Maximum Ratings Parameter Minimum Maximum Unit Input Power (PIN) — 15 dBm Supply Voltage (VCC), Standby, VAPC ≤ 0.3 V — 7 V Control Voltage (VAPC) –0.5 VCCMAX – 0.2 (See Table 3) V Storage Temperature –55 +150 °C Table 2. Recommended Operating Conditions Parameter Supply Voltage (VCC) Supply Current (ICC) Operating Case Temperature (TCASE) 1-Slot (12.5% duty cycle) 2-Slot (25% duty cycle) 3-Slot (37.5% duty cycle) 4-Slot (50% duty cycle) (1) Minimum Typical 2.9 3.5 Maximum Unit 4.8 (1) V (1) A 0 — 2.5 –20 –20 –20 –20 — — — — +100 +90 +85 +80 °C For charging conditions with VCC > 4.8 V, derate ICC linearly down to 0.5 A max at VCC = 5.5 V. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 2 September 9, 2005 • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • 103030B PA MODULE FOR TRI-BAND EGSM / GPRS DATA SHEET • SKY77321 Table 3. SKY77321 Electrical Specifications (1) (1 of 6) General Parameter Symbol Test Condition Minimum Typical Maximum Units Supply Voltage VCC — 2.9 3.5 4.8 V Power Control Current IAPC — — 10 100 µA Leakage Current IQ — — 5 µA APC Enable Threshold VAPCTH 200 — 500 mV APC Enable Switching Delay tSW 1 — 3 µs Test Condition Minimum Typical Maximum Units VCC = 4.5 V VAPC = 0.3 V TCASE = +25 °C PIN ≤ –60 dBm — Time from VAPC ≥ VAPCTH until POUT ≤ (POUT_FINAL – 3 dB) EGSM Mode (f = 880 to 915 MHz and PIN = 6 to 10 dBm) Parameter Symbol Frequency range f — 880 — 915 MHz Input power PIN — 6 — 10 dBm Analog power control voltage VAPC POUT = 32 dBm 1.2 1.7 2.1 V PAE VCC = 3.5 V POUT ≥ 35.0 dBm VAPC ≈ 2.0 V pulse width 577 µs duty cycle 1:8 TCASE = +25 °C 49 53 — PAELOW INPUT VCC = 3.5 V POUT ≥ 35.0 dBm VAPC ≈ 2.0 V pulse width 577 µs duty cycle 1:8 TCASE = +25 °C PIN = 4 dBm 48 50 — 2f0 to 13f0 BW = 3 MHz 5 dBm ≤ POUT ≤ 34.8 dBm — — –10 POUT VCC = 3.5 V VAPC ≈ 2.1 V TCASE = +25 °C 35.0 35.2 — POUTMAX LOW INPUT VCC = 3.5 V VAPC ≈ 2.1 V TCASE = +25 °C PIN = 4 dBm — — — POUTMAX LOW VOLTAGE VCC = 2.9 V VAPC ≤ 2.6 V TCASE = –20 °C to +100 °C (See Table 2 for multislot) PIN = 7 dBm — — — POUTMAX HIGH VOLTAGE VCC = 4.8 V VAPC ≤ 2.6 V TCASE = –20 °C to +100 °C (See Table 2 for multislot) PIN = 7 dBm — — — Power Added Efficiency 2nd to 13th harmonics Output power % dBm dBm Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 103030B • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • September 9, 2005 3 DATA SHEET • SKY77321 PA MODULE FOR TRI-BAND EGSM / GPRS Table 3. SKY77321 Electrical Specifications (1) (2 of 6) EGSM Mode (f = 880 to 915 MHz and PIN = 6 to 10 dBm) [continued] Parameter Symbol Test Condition Minimum Typical Maximum Input VSWR GIN POUT = 5 to 35.0 dBm, controlled by VAPC — — 2.5:1 Forward isolation POUT STANDBY PIN = 10 dBm VAPC = 0.3 V — –35 –30 Time from POUT = –10 dBm to POUT = +5 dBm τ ≈ 90% — 5 8 Time from POUT = –10 dBm to POUT = +20 dBm τ ≈ 90% — 5 8 Time from POUT = –10 dBm to POUT = +35.0 dBm τ ≈ 90% — 2 4 τRISE, τFALL Switching time Spurious Load mismatch Noise power Spur All combinations of the following parameters: VAPC = controlled (2) PIN = min. to max. VCC = 2.9 V to 4.8 V Load VSWR = 8:1, all phase angles No parasitic oscillation > –36 dBm Load All combinations of the following parameters: VAPC = controlled (2) PIN = min. to max. VCC = 2.9 V to 4.8 V Load VSWR = 10:1, all phase angles No module damage or permanent degradation PNOISE Coupling of 2nd and 3rd harmonic from the EGSM band into the DCS / PCS band 2f0, 3f0 At f0 + 20 MHz RBW = 100 kHz VCC = 3.5 V 5 dBm ≤ POUT ≤ 35.0 dBm — — –82 At f0 + 10 MHz RBW = 100 kHz VCC = 3.5 V 5 dBm ≤ POUT ≤ 35.0 dBm — — –76 At 1805 to 1880 MHz RBW = 100 kHz VCC = 3.5 V 5 dBm ≤ POUT ≤ 35.0 dBm — — –90 Measured at the DCS output –15 dBm ≤ POUT ≤ 35.0 dBm — –30 –20 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 4 September 9, 2005 • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • 103030B Units dBm µs dBm dBm PA MODULE FOR TRI-BAND EGSM / GPRS DATA SHEET • SKY77321 Table 3. SKY77321 Electrical Specifications (1) (3 of 6) DCS Mode (f = 1710 to 1785 MHz and PIN = 6 to 10 dBm) Parameter Symbol Test Condition Minimum Typical Maximum Units Frequency range f — 1710 — 1785 MHz Input power PIN — 6 — 10 dBm Analog power control voltage VAPC POUT = 29.5 dBm 1.35 1.7 2.1 V PAE VCC = 3.5 V POUT ≥ 33.0 dBm VAPC ≈ 2.1 V pulse width 577 µs duty cycle 1:8 TCASE = +25 °C 43 47 — PAELOW INPUT VCC = 3.5 V POUT ≥ 33.0 dBm VAPC ≈ 2.1 V pulse width 577 µs duty cycle 1:8 TCASE = +25 °C PIN = 4 dBm 43 46 — 2f0 to 7f0 BW = 3 MHz, 5 dBm ≤ POUT ≤ 33.0 dBm TCASE = +25 °C VCC = 3.5 V — — –10 POUT VCC = 3.5 V VAPC ≈ 2.1 V TCASE = +25 °C 33.0 33.2 — POUTMAX LOW INPUT VCC = 3.5 V VAPC ≈ 2.0 V TCASE = +25 °C PIN = 4 dBm — — — POUTMAX LOW VOLTAGE VCC = 2.9 V VAPC ≤ 2.6 V TCASE = –20 °C to +100 °C (See Table 2 for multislot) PIN = 6 dBm — — — POUTMAX HIGH VOLTAGE VCC = 4.8 V VAPC ≤ 2.6 V TCASE = –20 °C to +100 °C (See Table 2 for multislot) PIN = 6 dBm — 32.0 — Power Added Efficiency 2nd to 7th harmonic Output power % dBm dBm Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 103030B • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • September 9, 2005 5 DATA SHEET • SKY77321 PA MODULE FOR TRI-BAND EGSM / GPRS Table 3. SKY77321 Electrical Specifications (1) (4 of 6) DCS Mode (f = 1710 to 1785 MHz and PIN = 6 to 10 dBm) [continued] Parameter Symbol Test Condition Minimum Typical Maximum Units Input VSWR GIN POUT = 0 to 33.0 dBm, controlled by VAPC — — 2:1 — Forward isolation POUT STANDBY PIN = 10 dBm VAPC= 0.3 V — –36 –30 dBm Time from POUT = –10 dBm to POUT = 0 dBm τ ≈ 90% — 10 12 Time from POUT = –10 dBm to POUT = +20 dBm τ ≈ 90% — 5 8 Time from POUT = –10 dBm to POUT = +33.0 dBm τ ≈ 90% — 2 5 Switching time Spurious Load mismatch Noise power τRISE, τFALL Spur All combinations of the following parameters: VAPC = controlled (3) PIN = min. to max. VCC = 2.9 V to 4.8 V Load VSWR = 8:1, all phase angles No parasitic oscillation > –36 dBm Load All combinations of the following parameters: VAPC = controlled (3) PIN = min. to max. VCC = 2.9 V to 4.8 V Load VSWR = 10:1, all phase angles No module damage or permanent degradation PNOISE At f0 + 20 MHz RBW = 100 kHz VCC = 3.5 V 5 dBm ≤ POUT ≤ 33.0 dBm — At 925 to 960 MHz RBW = 100 kHz VCC = 3.5 V 5 dBm ≤ POUT ≤ 33.0 dBm — — –80 dBm — –95 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 6 µs September 9, 2005 • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • 103030B PA MODULE FOR TRI-BAND EGSM / GPRS DATA SHEET • SKY77321 Table 3. SKY77321 Electrical Specifications (1) (5 of 6) PCS Mode (f = 1850 to 1910 MHz and PIN = 6 to 10 dBm) Parameter Frequency range Symbol Test Condition Minimum Typical Maximum Units 1850 — 1910 MHz f — Input power PIN — Analog power control voltage VAPC POUT = 29.5 dBm PAE VCC = 3.5 V POUT ≥ 33.0 dBm VAPC ≈ 2.1 V pulse width 577 µs duty cycle 1:8 TCASE = +25 °C PAELOW INPUT VCC = 3.5 V POUT ≥ 33.0 dBm VAPC ≈ 2.1 V pulse width 577 µs duty cycle 1:8 TCASE = +25 °C PIN = 4 dBm 43 46 — 2f0 to 7f0 BW = 3 MHz 5 dBm ≤ POUT ≤ 33.0 dBm — — –10 POUT VCC = 3.5 V VAPC ≈ 2.1 V TCASE = +25 °C 33.0 33.2 — POUTMAX LOW INPUT VCC = 3.5 V VAPC ≈ 2.1 V TCASE = +25 °C PIN = 4 dBm — — — POUTMAX LOW VOLTAGE VCC = 2.9 V VAPC ≤ 2.6 V TCASE = –20 °C to +100 °C (See Table 2 for multislot) PIN = 6 dBm — — — POUTMAX HIGH VOLTAGE VCC = 4.8 V VAPC ≤ 2.6 V TCASE = –20 °C to +100 °C (See Table 2 for multislot) PIN = 6 dBm — — — Input VSWR GIN POUT = 0 to 33.0 dBm, controlled by VAPC — — 2:1 — Forward isolation POUT STANDBY PIN = 10 dBm VAPC = 0.3 V — –36 –30 dBm Time from POUT = –10 dBm to POUT = 0 dBm τ ≈ 90% — 10 12 Time from POUT = –10 dBm to POUT = 20 dBm τ ≈ 90% — 5 8 Time from POUT = –10 dBm to POUT = +33.0 dBm τ ≈ 90% — 2 5 Power Added Efficiency 2nd to 7th harmonics Output power Switching time τRISE, τFALL 6 — 10 dBm 1.35 1.7 2.1 V 43 47 — % dBm dBm µs Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 103030B • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • September 9, 2005 7 DATA SHEET • SKY77321 PA MODULE FOR TRI-BAND EGSM / GPRS Table 3. SKY77321 Electrical Specifications (1) (6 of 6) PCS Mode (f = 1850 to 1910 MHz and PIN = 6 to 10 dBm) [continued] Parameter Spurious Load mismatch Noise power Symbol Test Condition Minimum Typical Maximum Spur All combinations of the following parameters: VAPC = controlled (3) PIN = min. to max. VCC = 2.9 V to 4.8 V Load VSWR = 8:1, all phase angles No parasitic oscillation > –36 dBm Load All combinations of the following parameters: VAPC = controlled (3) PIN = min. to max. VCC = 2.9 V to 4.8 V Load VSWR = 10:1 all phase angles No module damage or permanent degradation PNOISE At f0 + 20 MHz RBW = 100 kHz VCC = 3.5 V 5 dBm ≤ POUT ≤ 33.0 dBm — At 869 to 894 MHz RBW = 100 kHz VCC = 3.5 V 5 dBm ≤ POUT ≤ 33.0 dBm — (1) Unless specified otherwise: TCASE = –20 to max. operating temperature (see Table 2), RL = 50 Ω, pulsed operation with pulse width ≤ 2308 µs and duty cycle ≤ 4:8, VCC = 2.9 V to 4.8 V. (2) ICC = 0A to xA, where x = current at POUT = 35.0 dBm, 50 Ω load, and VCC = 3.5 V. (3) ICC = 0A to xA, where x = current at POUT = 33.0 dBm, 50 Ω load, and VCC = 3.5 V. — –77 dBm — –95 Figure 2. Typical SKY77321 PAM Application (Top View) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 8 Units September 9, 2005 • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • 103030B PA MODULE FOR TRI-BAND EGSM / GPRS DATA SHEET • SKY77321 Package Dimensions and Pin Descriptions Figure 3 is a mechanical diagram of the pad layout for the 18-pin surface mount SKY77321 tri-band PA module. Figure 4 provides a recommended phone board layout footprint for the PAM to help the designer attain optimum thermal conductivity, good grounding, and minimum RF discontinuity for the 50-ohm terminals. Figure 5, illustrates the pin numbering convention, which starts with pin 1 in the upper left and increments counterclockwise around the package. Figure 6 translates the typical case markings of a Skyworks PA module and Table 4 provides a list of the pin names and their signal descriptions. Figure 3. SKY77321 PAM Package Dimensions – 18-Pin Module (All Views) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 103030B • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • September 9, 2005 9 DATA SHEET • SKY77321 PA MODULE FOR TRI-BAND EGSM / GPRS PCB SYMBOL FOR 6.0 x 6.0 mm PACKAGE (SKY77321) SPECIFIC 0.8 0.3 PITCH 0.8 0.30 PITCH 0.5 0.5 1 TYPICAL 1 TYPICAL 0.85 0.85 2 1.7 1.43 1.15 0.7 0.7 6.4 6.4 2X 1.5 x 0.8 2X 1.5 x 0.8 STENCIL APERTURE STENCIL APERTURE TOP VIEW APPROACH 2 TOP VIEW APPROACH 1 Common Ground 0.8 Pad Component Outline 2X 1.5 x 0.8 2X 1.6 x 0.9 0.9 0.2 0.6 0.5 1 TYPICAL 0.25 0.05 ALL AROUND 1 TYPICAL 6.4 METALLIZATION Thermal Via Array Ø 0.3 mm on 0.8 Pitch Additional vias will improve thermal performance. NOTE: Thermal Vias should be tented and filled with solder mask 30–35 mm Cu plating recommended. 3.8 6.5 SOLDER MASK OPENING TOP VIEW TOP VIEW 103030_004 All dimensions in millimeters. Figure 4. Phone Board Layout Footprint for 6 x 6 mm Package Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 10 September 9, 2005 • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • 103030B PA MODULE FOR TRI-BAND EGSM / GPRS DATA SHEET • SKY77321 Table 4. SKY77321 Pin Names and Signal Descriptions Pin Name Description 1 TX Enable Transmit Enable 2 VAPC Power Control Bias Voltage 3 DCS/PSC IN RF input 1710–1910 MHz 4 EGSM IN RF Input 880–915 MHz 5 BS Band Select 6 VCC DC Supply 7 GND RF and DC Ground 8 GND RF and DC Ground 9 GND RF and DC Ground 10 EGSM OUT RF Output 880–915 MHz 11 GND RF and DC Ground 12 VCC Final Stage DC supply 13 RESERVED Reserved 14 GND RF and DC Ground 15 DCS/PCS OUT RF Output 1710–1910 MHz 16 GND RF and DC Ground 17 GND RF and DC Ground 18 Vsupply DC Supply for CMOS Bias Controller GND Ground Pad, bottom Figure 5. SKY77321 Pin Configuration – 18 Pin Leadless PAM GND PAD Figure 6. Typical Case Markings Package and Handling Information Because of its sensitivity to moisture absorption, this device package is baked and vacuum-packed prior to shipment. Instructions on the shipping container label must be followed regarding exposure to moisture after the container seal is broken, otherwise, problems related to moisture absorption may occur when the part is subjected to high temperature during solder assembly. to temperatures exceeding 240 °C for more than 10 seconds. For details on both attachment techniques, precautions, and handling procedures recommended by Skyworks, please refer to Skyworks Application Note: PCB Design and SMT Assembly/Rework, Document Number 101752. Additional information on standard SMT reflow profiles can also be found in the JEDEC Standard J-STD–020B. The SKY77321 is capable of withstanding an MSL3/240 °C solder reflow. Care must be taken when attaching this product, whether it is done manually or in a production solder reflow environment. If the part is attached in a reflow oven, the temperature ramp rate should not exceed 5 °C per second; maximum temperature should not exceed 240 °C. If the part is manually attached, precaution should be taken to insure that the part is not subjected Production quantities of this product are shipped in the standard tape-and-reel format. Figure 7 shows tape and reel dimensions for the SKY77321 6 x 6 x 1.2 mm package. Figure 8 illustrates the orientation of the carrier tape on the reel and the unreeling direction. For additional packaging details, refer to Skyworks Application Note: Tape and Reel Information – RF Modules, Document Number 101568. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 103030B • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • September 9, 2005 11 DATA SHEET • SKY77321 PA MODULE FOR TRI-BAND EGSM / GPRS Figure 7. Tape and Reel for 6 x 6 mm Package Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 12 September 9, 2005 • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • 103030B PA MODULE FOR TRI-BAND EGSM / GPRS DATA SHEET • SKY77321 Figure 8. Typical Tape and Reel Orientation and Unreeling Direction (Front and Top Views) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 103030B • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • September 9, 2005 13 DATA SHEET • SKY77321 PA MODULE FOR TRI-BAND EGSM / GPRS Electrostatic Discharge Sensitivity Technical Information The SKY77321 is a Class I device. Figure 9 lists the Electrostatic Discharge (ESD) immunity level for each non-ground pin of the SKY77321 product. The numbers in Figure 9 specify the ESD threshold level for each pin where the I-V curve between the pin and ground starts to show degradation. ESD testing was performed in compliance with MIL-STD-883E Method 3015.7 using the Human Body Model. If the ESD damage threshold magnitude is found to consistently exceed 2000 volts on a given pin, this so is indicated. If ESD damage threshold below 2000 volts is measured for either polarity, numbers are indicated that represent worst case values observed in product characterization. CMOS Bias Controller Characteristics Various failure criteria can be utilized when performing ESD testing. Many vendors employ relaxed ESD failure standards, which fail devices only after “the pin fails the electrical specification limits” or “the pin becomes completely nonfunctional”. Skyworks employs most stringent criteria, fails devices as soon as the pin begins to show any degradation on a curve tracer. The CMOS die within the PAM performs several functions that are important to the overall module performance. Some of these functions must be considered for development of the power ramping features in a 3GPP compliant transmitter power control loop. Power ramping considerations will be discussed later in this section. NOTE: Please refer to 3GPP TS 05.05, Digital Cellular Communications System (Phase 2+), Radio Transmission and Reception. All GSM specifications are now the responsibility of 3GPP. The standards are available at http://www.3GPP.org/specs/specs.htm The four main functions that will be described in this section are Standby Mode Control, Band Select, Voltage Clamp, and Current Buffer. The functional block diagram is shown in Figure 10. Band Select (pin 5) To avoid ESD damage, latent or visible, it is very important the Class-1 ESD handling precautions listed in Table 5 be used in the product assembly and test areas. APC input (pin 4) cpdcs vodcs Supply (pin 2) vogsm cpgsm Ccomp Ccomp Combinational Logic Voltage Clamp Bandgap Reference CMOS Bias Controller DCS1800/ PCS1900 bias out Cbypass ground Cbypass RF Isolation GSM900 bias out RF Isolation Tri Band Power Amplifier GaAs Die 103030_010 Figure 10. Functional Block Diagram Figure 9. ESD Sensitivity Areas (Top View) Table 5. Precautions for Handling GaAs IC-based Products to Avoid Induced Damage Personnel Grounding Wrist Straps Conductive Smocks, Gloves and Finger Cots Antistatic ID Badges Protective Workstation Dissipative Table Tops Protective Test Equipment (Properly Grounded) Grounded Tip Soldering Irons Conductive Solder Suckers Static Sensors Facility Relative Humidity Control and Air Ionizers Dissipative Floors (less than 109 Ω to GND) Protective Packaging & Transportation Bags and Pouches (Faraday Shield) Protective Tote Boxes (Conductive Static Shielding) Protective Trays Grounded Carts Protective Work Order Holders Standby Mode Control The Combinational Logic cell includes enable circuitry that monitors the APC ramping voltage from the power amplifier controller (PAC) circuit in the EGSM transmitter. Typical handset designs directly connect the PA VCC to the battery at all times, and for some PA manufacturers this requires a control signal to set the device in or out of standby mode. The Skyworks PAM does not require a Transmit Enable input because it contains a standby detection circuit that senses the VAPC to enable or disable the PA. This feature helps minimize battery discharge when the PA is in standby mode. When VAPC is below the enable threshold voltage, the PA goes into a standby mode, which reduces battery current (ICC) to 6 µA, typical, under nominal conditions. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 14 September 9, 2005 • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • 103030B PA MODULE FOR TRI-BAND EGSM / GPRS DATA SHEET • SKY77321 For voltages less than 500 mV at the APC input (pin 4), the PA bias is held at ground. As the APC input exceeds the enable threshold, the bias will activate. After a 3 µs delay, the amplifier internal bias will ramp quickly to match the ramp voltage applied to the APC input. In order for the internal bias to precisely follow the APC ramping voltage, it is critical that a ramp pedestal is set to the APC input at or above the enable threshold level with a timing at least 3 µs prior to ramp-up. This will be discussed in more detail in the following section, “Power Ramping Considerations for 3GPP Compliance”. Band Select The Combinational Logic cell also includes a simple gate arrangement that selects the desired operational band by activating the appropriate current buffer. The voltage threshold level at the Band Select input (pin 5) will determine the active path of the bias output to the GaAs die. Voltage Clamp The Voltage Clamp circuit will limit the maximum bias voltage output applied to the bases of the HBT devices on the GaAs die. This provides protection against electrical overstress (EOS) of the active devices during high voltage and/or load mismatch conditions. Figure 11 shows the typical transfer function of the APC input to buffer output under resistively loaded conditions. Notice the enable function near 500 mV, and the clamp acting at 2.15 V, corresponding to a supply voltage of 4.0 V. Figure 12. Base Bias Clamp Voltage vs. Supply Voltage Current Buffer The output buffer amplifier performs a vital function in the CMOS device by transferring the APC input voltage ramp to the base of the GaAs power devices. This allows the APC input to be a high impedance port, sinking only 10 µA, typical, assuring no loading effects on the PAC circuit. The buffers are designed to source the high GaAs base currents required, while allowing a settling time of less than 3 µs for a 1.5 V ramp. Power Ramping Considerations for 3GPP Compliance The system designer must control these primary variables in the power control loop: • software control of the DSP / DAC • software control of the transmitter timing signals • ramp profile attributes – pedestal, number of steps, duration of steps • layout of circuit / parasitics • RC time constants within the PAC circuit design All of these variables will directly influence the ability of an EGSM transmitter power control loop to comply with 3GPP specifications. Figure 11. Base Bias Voltage vs. APC Input—VCC = 4.0 V Due to output impedance effects, the bias of the GaAs devices increases as the supply voltage increases. The Voltage Clamp is designed to gradually decrease in level as the battery voltage increases. The performance of the clamp circuit is enhanced by the band gap reference that provides a supply-, process-, and temperature-independent reference voltage. The transfer function relative to VBAT is shown in Figure 12. For battery voltages below 3.4 V, the base bias voltage is limited by the common mode range of the buffer amplifier. For battery voltages above 3.4 V, the clamp limits the base bias. Although there is a specific time mask template in which the transmitter power is allowed to ramp up, the method is very critical. The 3GPP system specification for switching transients causes the requirement to limit the edge rate of output power transitions of the mobile. Switching transients are caused by the transition from minimum output power to the desired output power, and vice versa. The spectrum generated by this transition is due to the ramping waveform amplitude modulation imposed on the carrier. Sharper transitions tend to produce more spectral “splatter” than smooth transitions. If the transmit output power is ramped up too slowly, the radio will violate the time mask specification. In this condition, the radio may not successfully initiate or maintain a phone call. If the transmit output power is ramped up too quickly, this will cause RF “splatter” at certain frequency offsets from the carrier as dictated by the 3GPP Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 103030B • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • September 9, 2005 15 DATA SHEET • SKY77321 specification. This splatter, known as Output RF Spectrum (ORFS) due to Switching Transients, will increase the system noise level, which may knock out other users on the system. The main difficulty with TDMA power control is allowing the transmitter to ramp the output power up and down gradually so switching transients are not compromised while meeting the time mask template at all output power levels in all operational bands. The transmitter has 28 µs to ramp up power from an off state to the desired power level. The EGSM transmitter power control loop generally involves feedback around the GaAs PA, which limits the bandwidth of signals that can be applied to the PA bias input. Since the PA is within the feedback loop, its own small-signal frequency response must exhibit a bandwidth 5 to 10 times that of the power control loop. As discussed in the previous section, the PA bias is held at ground for inputs less than 500 mV. As the APC input exceeds the enable threshold, the bias will activate. After a 3 µs delay, the amplifier internal bias will quickly ramp to match the ramp voltage applied to the VAPC input. Since the bias must be wide band relative to the power control loop, the ramp will exhibit a fast edge rate. If the APC input increases beyond 1 V before the 3 µs switching delay is allowed to occur after the bias is enabled, the PA will have significant RF output as the internal bias approaches the applied bias. During this ramp, the internal power control is running “open loop" and the edge rates are defined by the frequency response of the PA bias rather than that of the power control loop. This open loop condition will result in switching transients that are directly correlated to the PA bias bandwidth. Application of an initial APC voltage, which enables the bias at least 3 µs before the VAPC voltage is ramped, will ensure that the internal bias of the PAM will directly follow the applied VAPC. As a result, the power control loop will define all edge transitions rather than the PA internal bandwidth defining the transition. Figure 13 and Figure 14 show the relationship of the internal bias relative to the applied APC in two cases. One case has ramping starting from ground; the other case has ramping starting with an initial enable pedestal of 500 mV. It is evident that the pedestal level is critical to ensure a predictable and well-behaved power control loop. PA MODULE FOR TRI-BAND EGSM / GPRS The device specifications for enable threshold level and switching delay are shown in Table 3. Figure 13. PAM Internal Bias Performance – No Pedestal Applied Figure 14. PAM Internal Bias Performance – Pedestal Applied To enable the CMOS driver in the PAM prior to ramp-up, a PAC output pedestal level to the APC input of the PAM (pin 4) should be set to about 500 mV. This pedestal level should have a duration of at least 3 µs directly prior to the start of ramp up. Figure 15 shows typical signals and timings measured in an EGSM transmitter power control loop. This particular example is at EGSM Power Level 5, Channel 62. The oscilloscope traces are TxVCO_enable, PAC_enable, DAC Ramp, and VAPC (pin 4). Note: When the TxVCO is enabled, the pedestal becomes set at the APC input of the PAM, then the PAC is enabled, and finally the DAC ramp begins. Figure 15. EGSM Transmitter - Typical Ramp-up Signals Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 16 September 9, 2005 • Skyworks Proprietary and Confidential information. • Products and product information are subject to change without notice. • 103030B Ordering Information Model Number Manufacturing Part Number SKY77321 SKY77321 Product Revision Package Operating Temperature 18-pin MCM 6 x 6 x 1.2 mm –20 °C to +80 °C Revision History Revision Level Date Description A May 26, 2005 Initial Release B September 9, 2005 Add: Pb-free stamp (p1) References Application Note: PCB Design and SMT Assembly/Rework, Document Number 101752. Application Note: Tape and Reel Information – RF Modules, Document Number 101568 Standard SMT Reflow Profiles: JEDEC Standard J–STD–020B. © 2002–2005, Skyworks Solutions, Inc. All Rights Reserved. Information in this document is provided in connection with Skyworks Solutions, Inc. ("Skyworks") products. 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