STPAC01F2 ® IPAD™ RF DETECTOR FOR POWER AMPLIFIER CONTROL MAIN PRODUCT CHARACTERISTICS The STPAC01F2 has two outputs, one for the signal detection and another one for the temperature compensation: ■ VDCout = 0.88 V at 0.85 GHz at 10 dBm ■ VDCout = 1.07 V at 1.85 GHz at 10 dBm ■ Vsupply = 5 V max Lead free package ■ Flip-Chip (8 Bumps) DESCRIPTION The STPAC01F2 is an integrated RF detector for the power control stage. It converts RF signal coming from the coupler into a DC signal usable by the digital stage. It is based on the use of two similar diodes, one providing the signal detection while the second one is used to provide a temperature information to thermal compensation stage. A biasing stage suppresses the detection diode drop voltage effect. Table 1: Order Code Part Number STPAC01F2 Marking RA Figure 1: Pin Configuration (Ball side) Target applications are cellular phones and PDA using GSM, DCS, PCS, AMPS, TDMA, CDMA and 800 MHz to 1900 MHz frequency ranges. 3 2 1 DC out V Temp Gnd1 Gnd1 Gnd2 B RFin Gnd1 Bias C A BENEFITS ■ The use of IPAD technology allows the RF front-end designer to save PCB area and to drastically suppress parasitic inductances. Figure 2: Functional diagram Coupler VBIAS RF input RF detector Low pass filter Thermal compensation VDCOut Vtemp STPAC01F2 GND1 October 2004 REV. 1 GND2 1/7 STPAC01F2 Table 2: Absolute Retings (Tamb = 25°C) Symbol Value Unit Bias voltage 5 V PRF RF power at the RF input 20 dBm FOP Operating frequency range 0.8 to 2 GHz VPP ESD level as per MIL-STD 883E method 3015.7 notice 8 (HBM) 250 V TOP Operating temperature range - 30 to + 85 °C TSTG Storage temperature range - 55 to + 150 °C VBIAS Parameter and test conditions ELECTRICAL CHARACTERISTICS (Tamb = 25°C) Table 3: Parameters related to BIAS voltage Symbol Parameter VBIAS Operating bias voltage IBIAS Bias current Test conditions Min. Typ. 2.2 VBIAS = 3.2 V Max. Unit 3.2 V 0.5 mA Table 4: Parameters related detection function (VBIAS + 2.7 V, DC output load = 100kΩ) Symbol VDCout ∆VDCout Parameter DC output voltage (see fig. 1, IDC = 50 µA) DC output voltage variation (see fig. 8, IDC = 50µA) Test conditions Min. Typ. Max. Unit F = 1.85 GHz, PRF = 10 dBm 0.97 1.07 1.17 V F = 1.85 GHz, PRF = - 20 dBm 1.83 1.93 2.03 F = 0.85 GHz, PRF = 10 dBm 0.78 0.88 0.98 F = 0.85 GHz, PRF = - 20 dBm 1.83 1.93 2.03 0 < Tamb < 70°C F = 1.85 GHz, PRF = 10 dBm 0.09 2.2 < VBIAS < 3.2 V F = 1.85 GHz, PRF = 10 dBm 0.44 V Table 5: Parameters related to detection function Symbol Parameter Test conditions Min. Typ. Max. Unit 1.83 1.93 2.03 V VTemp Temperature output voltage (see fig. 9) IDC = 50µA ∆VTemp Temperature output voltage variation (see fig. 9) IDC = 50µA, 0 < Tamb < 70°C 0.09 IDC = 50µA, 2.2 < VBIAS < 3.2V 0.44 2/7 V STPAC01F2 Figure 3: Application diagram Coupler VBIAS IDC = 50µA RF input Low pass filter RF detector Thermal compensation VDCOut - Vtemp Out + STPAC01F2 IDC = 50µA GND1 GND2 The STPAC01 is the first part of the power amplifier stage and provides both RF power and die temperature measurements. The above figure gives the basic circuit of RF detector. A coupler located on the line between RF amplifier output and the antenna takes a part of the available power and applies it to STPAC01 RF input. The RF detector and the low pass filter provide a DC voltage depending on the input power. Thermal compensation provides a DC voltage depending on the ambient temperature. As the detection system and the thermal compensation are based on the same topology, VDCout will have the same temperature variation as Vtemp. Connected to a differential amplifier, the output will be a voltage directly linked to the RF input power. VDCout and Vtemp must be bias with 50µA DC current. This topology offers the most accurate output value as it is 100% compensated. Figure 4: VDCout measurement circuit Figure 5: VDCout versus RF input power VDCout RF generator Power supply RF in STPAC test board VDCOut 2 Multimeter 1.8 DC output voltage VBIAS 1.6 1850MHz Tamb = 25°C Ibias = 50µA Vbias = 2.7V 1.4 850MHz 1.2 Current generator IDC 1 0.8 -20 -15 -10 -5 Pin (dBm) 0 5 10 3/7 STPAC01F2 Figure 6: Relative variation of VDCout versus frequency (from 800 to 900 MHz) Figure 7: Relative variation of VDCout versus frequency (from 1800 to 1900 MHz) VDCout (Freq.) / VDCOut (850MHz) VDCout (Freq.) / VDCOut (850MHz) 1.05 1.05 1 1 0.95 0.95 0.9 800 825 850 875 900 0.9 1800 Frequency in MHz 1825 1850 Figure 8: Temperature effect measurement circuit on VDCout RF in STPAC test board Climatic chamber VDCOut Power supply IDC Current generator Current generator Figure 10: Vtemp output ambient temperature voltage versus Vtemp 1.98 Ibias = 50µA 1.96 1.94 1.92 1.9 1.88 0 10 20 30 40 Tamb (°C) 4/7 STPAC test board Multimeter DC output voltage VBIAS Power supply 1900 Figure 9: Vtemp measurement circuit Climatic chamber RF generator 1875 Frequency in MHz 50 60 70 Vtemp Multimeter Temp. voltage VBIAS IDC STPAC01F2 Figure 11: FLIP-CHIP Package Mechanical Data 500µm ± 50 650µm ± 65 1.57mm ± 50µm 500µm ± 50 315µm ± 50 1.57mm ± 50µm Figure 12: Foot print recommendations Copper pad Diameter : 250µm recommended , 300µm max Solder stencil opening : 330µm Solder mask opening recommendation : 340µm min for 300µm copper pad diameter Figure 13: Marking 365 240 365 Dot, ST logo xx = marking z = packaging location yww = datecode (y = year ww = week) E 40 220 x x z y ww All dimensions in µm 5/7 STPAC01F2 Figure 14: FLIP-CHIP Tape and Reel Specification Dot identifying Pin A1 location 1.75 +/- 0.1 Ø 1.5 +/- 0.1 4 +/- 0.1 3.5 +/- 0.1 ST E xxz yww ST E xxz yww ST E xxz yww 8 +/- 0.3 0.73 +/- 0.05 4 +/- 0.1 User direction of unreeling All dimensions in mm Table 6: Ordering Information Ordering code Marking Package Weight Base qty Delivery mode STPAC01F2 RA Flip-Chip 3.3 mg 5000 Tape & reel 7” Note: More informations are available in the application notes: AN1235: “Flip-Chip: Package description and recommendations for use” AN1751: "EMI Filters: Recommendations and measurements" Table 7: Revision History 6/7 Date Revision 21-Oct-2004 1 Description of Changes First issue STPAC01F2 Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics. 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