H Philips Semiconductors B.V. Gerstweg 2, 6534 AE Nijmegen, The Netherlands Report nr. Author Date Department : RNR-T45-96-B-770 : T. Buss : 20-Jan-00 : P.G. Transistors & Diodes, Development 900MHz LOW NOISE AMPLIFIER WITH THE BFG410W Abstract: This application note contains an example of a Low Noise Amplifier with the new BFG410W Double Poly RF-transistor. The LNA is designed for a frequency f=900MHz. The Noise Figure NF~1.4dB at f=900MHz and the gain S21 ~14dB. Appendix I: 900MHz LNA circuit Appendix II: Printlayout and list of used components & materials Appendix III: Results of simulations and measurements 1 H Philips Semiconductors B.V. Introduction: With the new Philips silicon bipolar double poly BFG400W series, it is possible to design low noise amplifiers for high frequency applications with a low current and a low supply voltage. These amplifiers are well suited for the new generation low voltage high frequency wireless applications. In this note a first study of such an amplifier will be given. This amplifier is designed for a working frequency of 900MHz. Designing the circuit: The circuit is designed to show the following performance: transistor: BFG410W Vce=2V, Ic =2mA, VSUP~3.3V freq=900MHz Gain~15dB NF<=1.3dB VSWRi<1:2 VSWRo<1:2 In the simulations the effect of extra RF-noise caused by the SMA-connectors was omitted, so in the practical situation the NF is ~0.1dB higher. This LNA is not optimised for the highest IP3. The IP3 can be optimised by: I. an extra series RC-decoupling of the base to the ground II. increasing IC With the solution I. two extra components are necessary, and with solution II, the Noise Figure of the LNA increases and the optimum source impedance also. The in- and outputmatching is realised with a LC-combination. Also extra emitter-inductance on both emitterleads (µ-strips) are used to improve the matching and the Noise Figure. Designing the layout: A lay-out has been designed with HP-MDS. Appendix II contains the printlayout. Measurements: Simulations (with realistic RF-models of al used parts) and measurements of the total circuit (epoxy PCB) are done (Appendix III). 2 H Philips Semiconductors B.V. Appendix I: Schematic of the circuit C6 C3 R5 C4 R1 +VSUP C2 R3 R4 Coil_2 Coil_1 R2 OUT 50Ω C5 IN 50Ω C7 W1 C1 BFG410W µS4: µS4 L1 L2 µS4 D1 L3 W2 Figure 1: LNA circuit 900MHz LNA Component list: Component: Value: Comment: R1 R2 R3 R4 R5 C1 C2 C3 C4 C5 C6 C7 Coil_1 Coil_2 µs4 Bias. Better RF-stability (K>1). RF-block. Cancelling HFE-spread. To improve IP3-performance Input match. 900MHz short. 900MHz short. RF-short Output match. To improve IP3-performance Better RF-stability (K>1). Input match. Output match. Emitter induction: µ-stripline + via 47 120 22 560 100 2.2 27 27 1 1.5 100 0.47 12 15 (next KΩ Ω Ω Ω Ω pF pF pF nF pF nF pF nH nH table) 3 H Philips Semiconductors B.V. µS4 Emitter induction (µ-stripline + via): Name Dimension Description L1 2.0mm length µ-stripline; Z0 ~48Ω (PCB: εr ~4.6, H=0.5mm) L2 1.0mm length interconnect stripline and via-hole area L3 1.0mm length via-hole area W1 0.5mm width µ-stripline W2 1.0mm width via-hole area D1 0.4mm diameter of via-hole 4 H Philips Semiconductors B.V. Appendix II: Printlayout and list of used components & materials RFin C1 C7 R5 C6 C5 RFout L1 R2 C2 C4 L2 R1 Vsup R4 R3 C3 Figure 2: 900MHz LOW NOISE AMP. PRINT LAYOUT Component list: Component: Value: size: R1 R2 R3 R4 R5 C1 C2 C3 C4 C5 C6 C7 L1 L2 PCB 47 KΩ 120 Ω 22 Ω 560 Ω 100 Ω 2.2 pF 27 pF 27 pF 1 nF 1.5 pF 100 nF 0.47 pF 12 nH 15 nH εr~4.6, H=0.5mm 0603 Philips 0603 Philips 0603 Philips 0603 Philips 0805 Philips 0603 Philips 0603 Philips 0603 Philips 0603 Philips 0603 Philips 0805 Philips 0603 Philips 0805CS Coilcraft 0805CS Coilcraft FR4 5 H Philips Semiconductors B.V. Appendix III: Results of simulations en measurements BFG410W, VCE=2V, IC=2mA: Simulation (HP-MDS): 2 |S21| [dB] 14.6 VSWRi 2.0 VSWRo 2.4 Noise Figure [dB] 1.3 IP3 [dBm] (input) - Measurements PCB: 14.0 1.9 2.3 *) 1.4 -9 Comment: ∆f=100KHz *) : The Noise Figure of the PCB is higher than the simulations (~0.1 dB). This is caused by the influence of the SMA-connectors and the microstrips on the epoxi PCB. CMP230 MSVIA W=Wvia OD=0.4 SUBST=s10mil mm W=Wvia L=Lvia CMP231 MSTL SUBST=s10mil L=1 nH CMP265 L CMP427 R_nor 1 2 CMP263 C R1=100 model cap. 1nF C=1 nF L=1 nH CMP417 L CMP286 MSVIA LOW NOISE AMP. WITH BFG425W@2V/5mA SUBST=s10mil OD=0.4 W=Wvia mm CMP264 R L=Lvia W=Wvia CMP287 MSTL CMP418 C R=0.3 OH C=100 nF SUBST=s10mil R1=22 OH R1=560 OH 1 2 CMP419 R CMP289 cmc_0603_phil Ccmc=Contkop W=0.5 mm L=0.5 mm SUBST=s10mil R=0.3 OH CMP428 R_nor L=100 uH CMP405 MSTL Lx=Lin W=W3 L=L3 SUBST=s10mil SUBST=s10mil L=0.5 mm W=0.5 mm SB1/BFG425W@2V/5mA CMP257 TWOPORT CMP383 MSTL SUBST=s10mil L=3 mm W=0.5 CMP409mm CMP203 cmc_0603_phil MSTL smd DATA=BFG425W_5mA.DATA.,FREQ=freq W=W3CMP408 MSTL L=L3 SUBST=s10mil Lx=Lout R1=Rout CMP358 MSTL CMP394 coilcraft_l1008_cs CMP197 cmc_0603_phil SUBST=s10mil L=0.5 mm W=0.5 mm 1 2 CMP431 SUBST=s10mil R_nor L=L4 W=W4 Ccmc=Cin CMP359 MSTL CMP18 PORT_SPAR vswri=(1+mag(s11))/(1-mag(s11)) vswro=(1+mag(s22))/(1-mag(s22)) Cin=(4.7) pF Cout=(2.7) pF Lin=(10) nH Lout=(10) nH EQUATION Contkop=(27) pF EQUATION EQUATION EQUATION EQUATION L1=(2.5) mm L2=(1) mm L3=(0.5) mm L4=(0.2) mm EQUATION Lvia=(0.25) mm EQUATION Wvia=(1) mm EQUATION Wvia_e=(1) mm EQUATION W3=(0.5) mm EQUATION W4=(0.5) mm SUBST=s10mil L=0.5 mm W=0.5 mm CMP438 cmc_0603_phil CMP350 MSTL CMP351 MSTL W=0.5 L=L1 SUBST=s10mil mm W=0.5 L=L1 SUBST=s10mil mm CMP227 MSTL W=W50_Ohm L=6 mm SUBST=s10mil HU=1.0E+3 m T=35um CMP252 MSTAPER SUBST=s10mil W1=Wvia_e L=L2 H=0.5mm W1=Wvia_e SUBST=s10mil L=L2 EQUATION W50_Ohm=(0.9) mm EQUATION Rout=(27) EQUATION Cce=(0.47) pF CMP180 MSVIA W=Wvia_e OD=0.4 mm CMP210 MSVIA W=Wvia_e OD=0.4 mm SUBST=s10mil SUBST=s10mil 6 Ccmc=Cout CMP403 MSTL PORTNUM=2 CMP270 PORT_SPAR R=50 JX=0 AGROUND CMP5 MSSUBSTRATE W2=0.5 mm W2=0.5 mm CMP250 MSTAPER Ccmc=Cce SUBST=s10mil ER=4.6 MUR=1 COND=5.8e07 ROUGH=10 um TAND=0.02 W=Wvia L=Lvia SUBST=s10mil Ccmc=Contkop 1 2 CMP401 PORTNUM=1 MSTL R=50 JX=0 EQUATION EQUATION EQUATION EQUATION AGROUND EQUATION EQUATION AGROUND CMP406 MSTL CMP236 MSTL CMP399 coilcraft_l1008_cs CMP281 cmc_0603_phil CMP429 R_nor 1 2 R1=47k smd W=W50_Ohm L=6 mm SUBST=s10mil CMP235 L 1 2 CMP430 R_nor CMP266 MSVIA SUBST=s10mil OD=0.4 mm W=Wvia