Application Note, Rev. 1.2, November 2008 Application Note No. 168 BFP740F SiGe:C Ultra Low Noise RF Transistor in 5 – 6 GHz LNA Application with 16 dB Gain, 1.3 dB Noise Figure & 1 microsecond Turn-On / Turn-Off Time (For 802.11a & 802.11n “MIMO” Wireless LAN Applications) Small Signal Discretes Never stop thinking Edition 2008-11-14 Published by Infineon Technologies AG 81726 München, Germany © Infineon Technologies AG 2008. All Rights Reserved. LEGAL DISCLAIMER THE INFORMATION GIVEN IN THIS APPLICATION NOTE IS GIVEN AS A HINT FOR THE IMPLEMENTATION OF THE INFINEON TECHNOLOGIES COMPONENT ONLY AND SHALL NOT BE REGARDED AS ANY DESCRIPTION OR WARRANTY OF A CERTAIN FUNCTIONALITY, CONDITION OR QUALITY OF THE INFINEON TECHNOLOGIES COMPONENT. THE RECIPIENT OF THIS APPLICATION NOTE MUST VERIFY ANY FUNCTION DESCRIBED HEREIN IN THE REAL APPLICATION. INFINEON TECHNOLOGIES HEREBY DISCLAIMS ANY AND ALL WARRANTIES AND LIABILITIES OF ANY KIND (INCLUDING WITHOUT LIMITATION WARRANTIES OF NON-INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OF ANY THIRD-PARTY) WITH RESPECT TO ANY AND ALL INFORMATION GIVEN IN THIS APPLICATION NOTE. Information For further information on technology, delivery terms and conditions and prices please contact your nearest Infineon Technologies Office (www.infineon.com). Warnings Due to technical requirements components may contain dangerous substances. For information on the types in question please contact your nearest Infineon Technologies Office. Infineon Technologies Components may only be used in life-support devices or systems with the express written approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure of that life-support device or system, or to affect the safety or effectiveness of that device or system. Life support devices or systems are intended to be implanted in the human body, or to support and/or maintain and sustain and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may be endangered. Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time Application Note No. 168 Revision History: 2008-11-07, Rev 1.0 2008-11-11, Rev 1.1 2008-11-14, Rev 1.2 Previous Version: Page Subjects (major changes since last revision) Cover Title change 3 Addition of weblinks 4 6 7 13 – 20 Update of summary values Updated Schematic (element values C1, C5, L1, L3) Updated Bill Of Material (values of C1, C5, L1, L3) Updated network analyzer plots Trademarks SIEGET® is a registered trademark of Infineon Technologies AG. Additional Information: More details about Infineon RF Transistors may be found at www.infineon.com/RF Direct link to RF Transistor Datasheets / Specifications: www.infineon.com/rf.specs For S-Parameters, Noise Parameters, SPICE models: www.infineon.com/rf.models For Application Notes: www.infineon.com/rf.appnotes Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time 1 BFP740F SiGe:C Ultra Low Noise RF Transistor in 5 – 6 GHz LNA Application with 16 dB Gain, 1.3 dB Noise Figure & 1 microsecond TurnOn / Turn-Off Time Overview • Infineon Technologies BFP740F is a high gain, ultra low noise Silicon-Germanium-Carbon (SiGe:C) HBT device suitable for a wide range of Low Noise Amplifier (LNA) applications. 2 • The circuit implementation shown in this document is targeted for 802.11a & 802.11n “MIMO” applications in the Wireless Local Area Network (WLAN) market, particularly for Access Points (AP’s) which require external LNA’s to fulfill high-sensitivity / long range requirements. LNA’s for this application must be able to switch on / off within about 1 microsecond. The charge storage (capacitance) used in the circuit is minimized to reduce turn-on / turn-off times. Tradeoff for reduced capacitance values is a reduction in Third Order Intercept (IP3) performance. Amplifier is Unconditionally Stable (µ1 > 1.0) from 10 MHz – 12 GHz. • External parts count (not including BFP740F transistor) = 12; 6 capacitors, 3 resistors, and 3 chip inductors. All passives are ‘0402’ case size. BFP740F transistor package is RoHS – compliant and measures 1.4 x 1.2 x 0.55mm. Summary Of Performance Data (T=25 °C, network analyzer source power ≈ -25 dBm, VCC = 3.0 V, VCE = 2.1 V, IC=14.8 mA, ZS=ZL=50 Ω ) Frequency * NF ** IIP3 ** OIP3 IP1dB OP1dB MHz dB[s11]2 dB[s21]2 dB[s12]2 dB[s22]2 dB dBm dBm dBm dBm - 10.9 -24.7 -9.2 --------5150 16.4 1.3 -12.7 -24.1 -10.3 +0.6 +22.1 -7.3 +7.8 5470 16.4 1.3 -10.9 -23.9 -14.3 --------5825 16.0 1.3 --------------2500 4.0 --* does not extract PCB loss. If PCB loss (at input) were extracted, noise figure would be ~ 0.2 dB lower. Note: reverse isolation ( dB[s12]2 ) when DC power to LNA is OFF = -13.7 dB @ 5470 MHz. 3 Details of PC Board Construction PC board is fabricated from standard, low-cost “FR4” glass-epoxy material. A cross-section diagram of the PC board is given below. PCB CROSS SECTION 0.012 inch / 0.305 mm TOP LAYER INTERNAL GROUND PLANE 0.028 inch / 0.711 mm ? LAYER FOR MECHANICAL RIGIDITY OF PCB, THICKNESS HERE NOT CRITICAL AS LONG AS TOTAL PCB THICKNESS DOES NOT EXCEED 0.045 INCH / 1.14 mm (SPECIFICATION FOR TOTAL PCB THICKNESS: 0.040 + 0.005 / - 0.005 INCH; 1.016 + 0.127 mm / - 0.127 mm ) BOTTOM LAYER Application Note 4 / 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time 4 TSFP-4 Package Outline and Footprint (Dimensions in millimeters). Note maximum package height is 0.59 mm / 0.023 inch. Recommended Soldering Footprint for TSFP-4 (dimensions in millimeters). Device package is to be oriented as shown in above drawing (e.g. orient long package dimension horizontally on this footprint). Application Note 5 / 24 Rev. 1.2, 2008-11-14 Application Note 6 / 24 C1 0.3pF RF INPUT C3 1.5pF C2 1.2pF L1 6.8nH R2 36K L2 R1 22 ohms R3 39 ohms C5 1.2pF C6 0.3pF cc J2 RF OUTPUT = 3.0 V = 50 ohm microstripline L3 1.2nH C4 33pF I = 14.8 mA Q1: VCE = 2.1 V Q1 1.5nH BFP740F SiGe Transistor PCB = 740F-080919 Rev A PC Board Material = Standard FR4 J1 6 capacitors 3 inductors 3 resistors 12 external passives used: V 5 Inductors are Murata LQP15M Series (formerly LQP10A) 0402 case size. Capacitors and resistors are 0402 case size. J3 DC Connector Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time Schematic Diagram Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time 6 Bill Of Material (BOM) Reference Designator Value C1 0.3pF C2 C3 C4 C5 1.2pF 1.5pF 33pF 1.2pF C6 0.3pF L1 6.8nH L2 Description / Part # Manufacturer 0.3pF, 50V, COG ‘0402’ case size capacitor Murata GRM1555C1HR30BZ01D or equivalent ‘0402’ chip capacitor ‘0402’ chip capacitor ‘0402’ chip capacitor ‘0402’ chip capacitor 0.3pF, 50V, COG ‘0402’ case size capacitor Murata GRM1555C1HR30BZ01D or equivalent Function Murata, AVX, etc. Input Match Various Various Various Various Murata, AVX, etc. Input DC block, Input Matching RF decoupling / blocking cap RF decoupling / blocking cap RF decoupling / blocking cap Output DC block and output matching. Also influences input match. 6.8nH ‘0402’ case size chip inductor Murata LQP15M Series or equivalent Murata 1.5nH 1.5nH ‘0402’ case size chip inductor Murata LQP15M series or equivalent Murata L3 1.2nH 1.2nH ‘0402’ case size chip inductor Murata LQP15M series or equivalent Murata RF Choke at LNA input (for DC bias to base). RF ‘Choke’ at LNA output, for DC bias to collector. Also influences matching and stability. Output matching; also influences input match. R1 R2 R3 22Ω 36KΩ 39Ω ‘0402’ chip resistor ‘0402’ chip resistor ‘0402’ chip resistor Various Various Various Q1 --- J1, J2 J3 --- Application Note BFP740F SiGe:C Low Noise RF Transistor, TSFP-4 package Infineon Technologies RF Edge Mount SMA Female Connector, 142-0701-841 MTA-100 Series 5 pin connector 640456-5 PC Board, Part # 740F-080919 Rev A 7 / 24 For RF stability improvement. DC biasing (base). DC biasing (provides DC negative feedback to stabilize DC operating point over temperature variation, transistor hFE variation, etc.) LNA active device. Emerson / Johnson Tyco (AMP) Input, Output RF connector Infineon Technologies Printed Circuit Board 5 Pin DC connector header Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time 7 Scanned Images of PC Board View of Entire PC Board Application Note 8 / 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time Close-In View of LNA Section Application Note 9 / 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time 8 Noise Figure Measurement Data Noise Figure Plot, from Rohde and Schwarz FSEK3 + FSEM30 Rohde & Schwarz FSEK3 05 Nov 2008 Noise Figure Measurement EUT Name: Manufacturer: Operating Conditions: Operator Name: Test Specification: Comment: BFP740F 5 - 6 GHz LNA, Fast Switching / Fast Turn ON-OFF Time Infineon Technologies T=25 C, V = 3.0V, Vce = 2.1V, I = 14.9mA Gerard Wevers WLAN 802.11n, 802.11n PCB = 740F-080919 Rev A; Preamp = MITEQ AFS3-04000800-10-ULN 5 November 2008 Analyzer RF Att: Ref Lvl: 0.00 dB -45.00 dBm RBW : VBW : 1 MHz 100 Hz Range: 30.00 dB Ref Lvl auto: ON Measurement 2nd stage corr: ON Mode: Direct ENR: 346A_1.ENR Noise Figure /dB 2.00 1.90 1.80 1.70 1.60 1.50 1.40 1.30 1.20 1.10 1.00 4800 MHz Application Note 120 MHz / DIV 10/ 24 6000 MHz Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time Noise Figure, Tabular Data Taken With Rohde & Schwarz FSEM30 + FSEK3 System Preamplifier = MITEQ 4 – 8 GHz LNA Frequency 4800 MHz 4850 MHz 4900 MHz 4950 MHz 5000 MHz 5050 MHz 5100 MHz 5150 MHz 5200 MHz 5250 MHz 5300 MHz 5350 MHz 5400 MHz 5450 MHz 5500 MHz 5550 MHz 5600 MHz 5650 MHz 5700 MHz 5750 MHz 5800 MHz 5850 MHz 5900 MHz 5950 MHz 6000 MHz Application Note Nf 1.31 dB 1.31 dB 1.32 dB 1.31 dB 1.31 dB 1.30 dB 1.26 dB 1.30 dB 1.29 dB 1.28 dB 1.24 dB 1.25 dB 1.26 dB 1.24 dB 1.27 dB 1.26 dB 1.28 dB 1.23 dB 1.26 dB 1.27 dB 1.29 dB 1.28 dB 1.29 dB 1.26 dB 1.29 dB 11/ 24 Temp 102.5 K 102 K 102.8 K 101.7 K 101.7 K 101.2 K 97.8 K 101 K 100.6 K 99.4 K 96.2 K 96.5 K 97.7 K 95.9 K 98.7 K 98 K 99.6 K 94.6 K 97.7 K 98.9 K 100.3 K 99.8 K 100.2 K 97.2 K 100.1 K Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time 9 Amplifier Compression Point Measurement Gain Compression at 5470 MHz, VCC = +3.0 V, I = 14.8mA, VCE = 2.1V, T = 25°C: Rohde & Schwarz ZVB20 Vector Network Analyzer is set up to sweep input power to LNA at a fixed frequency of 5470 MHz. X-axis of VNA screen-shot below shows input power to LNA being swept from –30 to –5 dBm. ZVB20 output power is checked / verified against HP E4419A power meter; ZVB20 output power is ≅ 0.6 dB lower than indicated on ZVB20 due to test cable loss. Therefore, a 0.6 dB offset is needed. Input 1 dB compression point = - 6.7 dBm – 0.6 dB offset = - 7.3 dBm Output 1dB compression point = - 7.3 dBm + (Gain – 1dB) = -7.3dBm + 15.1 dB = +7.8 dBm Trc1 S21 dB Mag 0.5 dB / Ref 16 dB Cal 1 M 1 -24.56 dBm • M 2 -6.66 dBm S21 16.5 16.081 dB 15.060 dB M1 16.0 15.5 M2 15.0 14.5 14.0 13.5 13.0 12.5 Ch1 Start -30 dBm Freq 5.47 GHz Stop -5 dBm 11/7/2008,9:37 AM Application Note 12/ 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time 10 Amplifier Stability, Gain, Return Loss and Reverse Isolation Plots Amplifier Stability - Plot of Stability Factor “ µ”: 1 Rohde and Schwarz ZVB Network Analyzer Calculates and plots stability factor “µ1” of the BFP740F amplifier in real time. Stability Factor µ1 is defined as follows [1]: µ 1 - |S11|2 1 = | S22 – S11* det(S) | + |S21S12| The necessary and sufficient condition for Unconditional Stability is µ1 > 1.0. In the plot, µ1 > 1.0 over 10 MHz – 12 GHz; amplifier is Unconditionally Stable over 10 MHz – 12 GHz frequency range. Trc1 µ1 Lin Mag 100 mU/ Ref 1 U Mem2[Trc1] S11 Lin Mag 100 mU/ Ref 1 U Cal Offs Invisible 1 M1 M2 M3 •M 4 µ1 1800 5.150000 5.470000 5.825000 2.483500 GHz GHz GHz GHz 1.1310 1.2012 1.3297 1.0329 U U U U 1700 1600 1500 1400 M3 1300 M2 1200 M1 1100 M4 1000 Ch1 Start 10 MHz Pwr -25 dBm Stop 12 GHz 11/14/2008,9:44 AM [1]. “Fundamentals of Vector Network Analysis”, Michael Hiebel, 4th edition 2008, pages 175 – 177, ISBN 978-3-939837-06-0 Application Note 13/ 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time Input Return Loss, Log Mag 10 MHz – 12 GHz Sweep Trc1 S11 dB Mag 3 dB / Ref 0 dB Mem2[Trc1] S11 dB Mag 3 dB / Ref 0 dB Cal Offs Invisible 1 M1 M2 M3 •M 4 S11 6 5.150000 5.470000 5.825000 2.483500 GHz GHz GHz GHz -10.894 -12.714 -10.972 -1.9309 dB dB dB dB 3 0 M4 -3 -6 -9 M1 M3 M2 -12 -15 -18 Ch1 Start 10 MHz Pwr -25 dBm Stop 12 GHz 11/14/2008,9:39 AM Application Note 14/ 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time Input Return Loss, Smith Chart Reference Plane = Input SMA Connector on PC Board 10 MHz – 12 GHz Sweep Trc1 S11 Smith Mem2[Trc1] S11 Smith Ref 1 U Ref 1 U Cal Offs Invisible 1 1 S11 0.5 M1 M2 0 0.2 0.5 57.680 j31.168 963.20 2 M 2 5.470000 GHz 77.030 j12.049 350.58 M 3 5.825000 GHz 69.318 5 -j28.953 943.68 • M 4 2.483500 GHz 6.4220 -j20.059 3.195 2 5 M 1 5.150000 GHz 1 Ω Ω pH Ω Ω pH Ω Ω fF Ω Ω pF M3 -5 M4 -0.5 -2 -1 Ch1 Start 10 MHz Pwr -25 dBm Stop 12 GHz 11/14/2008,9:40 AM Application Note 15/ 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time Forward Gain. Input / Output Matching Circuits of LNA reduce gain in 2.4 – 2.5 GHz band. 10 MHz – 12 GHz Sweep Trc1 S21 dB Mag 5 dB / Ref 0 dB Mem2[Trc1] S11 dB Mag 5 dB / Ref 0 dB Cal Offs Invisible M 1M 2M 3 S21 15 1 M1 M2 M3 •M 4 5.150000 5.470000 5.825000 2.483500 GHz GHz GHz GHz 16.421 16.363 15.986 4.0479 dB dB dB dB 10 M4 5 0 -5 -10 -15 -20 -25 Ch1 Start 10 MHz Pwr -25 dBm Stop 12 GHz 11/14/2008,9:41 AM Application Note 16/ 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time Reverse Isolation 10 MHz – 12 GHz Sweep Trc1 S12 dB Mag 10 dB / Ref 0 dB Mem2[Trc1] S11 dB Mag 10 dB / Ref 0 dB Cal Offs Invisible 1 M1 M2 M3 •M 4 S12 10 5.150000 5.470000 5.825000 2.483500 GHz GHz GHz GHz -24.660 -24.123 -23.861 -44.652 dB dB dB dB 0 -10 M 1M 2M 3 -20 -30 M4 -40 -50 -60 -70 Ch1 Start 10 MHz Pwr -25 dBm Stop 12 GHz 11/14/2008,9:41 AM Application Note 17/ 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time Reverse Isolation, AMPLIFIER DC POWER TURNED OFF. 10 MHz – 12 GHz Sweep Trc1 S12 dB Mag 10 dB / Ref 0 dB Mem2[Trc1] S11 dB Mag 10 dB / Ref 0 dB Cal Offs Invisible 1 M1 M2 M3 •M 4 S12 10 5.150000 5.470000 5.825000 2.483500 GHz GHz GHz GHz -14.601 -13.723 -12.140 -33.160 dB dB dB dB 0 M3 M 1M 2 -10 -20 M4 -30 -40 -50 -60 -70 Ch1 Start 10 MHz Pwr -25 dBm Stop 12 GHz 11/14/2008,9:42 AM Application Note 18/ 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time Output Return Loss, Log Mag 10 MHz to 12 GHz Sweep Trc1 S22 dB Mag 5 dB / Ref 0 dB Mem2[Trc1] S11 dB Mag 5 dB / Ref 0 dB Cal Offs Invisible 1 M1 M2 M3 •M 4 S22 10 5.150000 5.470000 5.825000 2.483500 GHz GHz GHz GHz -9.2165 -10.323 -14.328 -0.6761 dB dB dB dB 5 M4 0 -5 M1 M2 -10 M3 -15 -20 -25 -30 Ch1 Start 10 MHz Pwr -25 dBm Stop 12 GHz 11/14/2008,9:42 AM Application Note 19/ 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time Output Return Loss, Smith Chart Reference Plane = Output SMA Connector on PC Board 10 MHz to 12 GHz Sweep Trc1 S22 Smith Mem2[Trc1] S11 Smith Ref 1 U Ref 1 U Cal Offs Invisible 1 1 S22 102.72 -j3.7954 8.142 2 M 2 5.470000 GHz 73.382 -j30.880 942.21 M 3 5.825000 GHz 45.753 5 -j18.203 1.501 • M 4 2.483500 GHz 1.9190 j1.1342 M 12 72.682 5 M 1 5.150000 GHz 0.5 M4 0 0.2 0.5 1 M3 Ω Ω pF Ω Ω fF Ω Ω pF Ω Ω pH M2 -5 -0.5 -2 -1 Ch1 Start 10 MHz Pwr -25 dBm Stop 12 GHz 11/14/2008,9:43 AM Application Note 20/ 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time 11 Amplifier Third Order Intercept (TOI) Measurement In-Band Third Order Intercept (IIP3) Test. Input Stimulus: f1=5470 MHz, f2=5471 MHz, -23 dBm each tone. Input IP3 = -23 + (47.2 / 2) = +0.6 dBm. Application Note Output IP3 = +0.6 dBm + 16.1 dB gain = +22.1 dBm. 21/ 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time 12 Amplifier Turn-On / Turn-Off Time Measurements The amplifier is tested for turn-on / turn-off time. See diagram below. The RF signal generator runs continuously at a power level sufficient to drive the output of the LNA to approximately 0 dBm when the LNA has DC power ON. Agilent DSO6104A Digital Oscilloscope +3 Volts Ch. 1 (Trigger, edge) BFP740F Low Noise Amplifier Ch. 2 10 dB Attenuator Pad Agilent 8473B Detector Signal Generator f=5470 MHz 1. Signal Generator set such that output power of BFP740F LNA is approx. 0 dBm when LNA is powered ON 2. Channel 1 of oscilloscope monitors input power supply voltage to BFP740F LNA (+3.0 volts when ON, ~ 0 volts when OFF) 3. Channel 2 of oscilloscope monitors rectified RF output of BFP740F LNA 4. To make measurement of turn-on time, turn power supply OFF, reset o’scope, setup trigger to trigger on rising edge of Ch.1 5. To make measurement of turn-off time, turn power supply ON, reset o’scope, setup trigger to trigger on falling edge of Ch. 1 Application Note 22/ 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time a) Turn On Time: Refer to oscilloscope screen-shot below. Upper trace (yellow, Channel 1) is the DC power supply turnon step waveform whereas the lower trace (green, Channel 2) is the rectified RF output signal of the LNA stage. Amplifier turn-on time is aproximately 880 nanoseconds, or 0.9 microseconds. Main source of time delay in the LNA turn-on and turn-off events are the R-C time constants formed by (R3 * C4), [(R2+R3) * C3], etc. Charge storage has been minimized in this circuit so as to speed up turn on and turn off times. (Refer to Schematic diagram on page 3). Application Note 23/ 24 Rev. 1.2, 2008-11-14 Application Note No. 168 BFP740F 5 – 6 GHz LNA with 1µSec Turn-On / Turn-Off Time b) Turn-Off Time: Rectified RF output signal (lower green trace) takes about ~ 1 microsecond to settle out after power supply is turned off. Application Note 24/ 24 Rev. 1.2, 2008-11-14