RF2670 10 8MHZ DUAL BASEBAND AGC WITH PROGRAMMABLE LOW PASS FILTERING Typical Applications • Digital Cordless Telephones • Inventory Tracking • Secure Communication Links • Wireless Security • Wireless LANs • Battery Powered Applications Product Description .157 .150 The RF2670 is a monolithic integrated circuit specifically designed for direct conversion to baseband QPSK receivers. The part provides dual baseband amplifiers with a 70dB gain range (single pin analog input) and separate I and Q RSSI. On-chip programmable baseband filters are incorporated into each amplifier providing 1MHz, 2MHz, 4MHz, or 8MHz bandwidth with a 5-pole Bessel response. I and Q output are available in digital or analog form. The data comparators use a self generated DC reference to track DC offsets in the received signal. The analog outputs have a 500mVpp swing with approximately 1.7V DC offset. A 2.0V reference voltage is also available for A/D converters changing DC bias. GaAs MESFET SiGe HBT Si CMOS .012 .008 .344 .337 .025 .244 .228 .069 .053 8°MAX 0°MIN .050 .016 .010 .008 10 Package Style: SSOP-24 Features IF AMPLIERS ü GaAs HBT Si Bi-CMOS .010 .004 1 Optimum Technology Matching® Applied Si BJT .033 • I/Q Baseband Receivers IN Q+ 23 IN Q- 24 VCC1 VCC2 VCC3 • 10dB to 80dB Gain Range 20 5 8 • Digital and Analog Outputs 15 Q DATA 0-25 dB 0-20 dB -12-+12 17dB 6 dB 18 IF OUT Q 21 DCFB Q PD 11 BW SEL2 14 BW SEL1 13 • On-Chip Selectable IF Bandwidths • Reference Voltage for A/D Converter 10 RSSI I DC Bias 17 VREF 16 RSSI Q • 2.7V to 3.6V Operation 19 VGC IN I+ 2 IN I- 1 9 I DATA 7 IF OUT I 4 DCFB I Ordering Information RF2670 RF2670PCBA Functional Block Diagram Rev A4 010820 8MHz Dual Baseband AGC with Programmable Low Pass Filtering Fully Assembled Eval Board. RF Micro Devices, Inc. 7625 Thorndike Road Greensboro, NC 27409, USA Tel (336) 664 1233 Fax (336) 664 0454 http://www.rfmd.com 10-45 RF2670 Absolute Maximum Ratings Parameter Ratings Unit Supply Voltage Control Voltages Input RF Level Operating Ambient Temperature Storage Temperature -0.5 to +3.6 -0.5 to +3.6 +20 -40 to +85 -40 to +150 VDC VDC dBm °C °C Parameter Specification Min. Typ. Max. Caution! ESD sensitive device. RF Micro Devices believes the furnished information is correct and accurate at the time of this printing. However, RF Micro Devices reserves the right to make changes to its products without notice. RF Micro Devices does not assume responsibility for the use of the described product(s). Unit Baseband Amplifiers Frequency Range Voltage Gain Noise Figure 0.01 8 MHz 83 -0.08 500 dB dB dB dBm dBm mV dB V dB/mV mVPP 1 55 1.7 1.64 60 0.5 to 2.4 V VPP dB V 1.5 2 77 Input IP3 Output DC offset Gain Control Range Gain Control Voltage Range Gain Control Sensitivity VGA Output Voltage IF AMPLIERS 10 VGA DC Output Voltage Output P1dB RSSI Range RSSI Output Voltage Compliance Input Impedance 65 1.2 80 5 35 -65 +2 0 70 25 2.0 2.5 kΩ Condition T=25°C, VCC =3.0V Minimum frequency is dependent upon input blocking cap, DC feedback cap, and gain setting. Recommended components yields a minimum frequency of less than 10kHz. At maximum gain setting At minimum gain setting At maximum gain setting At minimum gain setting Driving a 5kΩ load At maximum gain setting Maximum RSSI is 2.5V or VCC -0.3, whichever is less. Differential Integrated Filters Characteristics Five pole Bessel Bandwidth 1, 2, 4, 8 Passband Ripple Group Delay Ultimate Rejection MHz 1 100 50 dB ns 80 dB 100 dB MHz ns V Five pole Bessel internal LPF. Three pole external LPF. Selectable from 1MHz, 2MHz, 4MHz, and 8MHz. At 8MHz, increasing as bandwidth decreases. Data Amplifiers Voltage Gain Bandwidth Rise and Fall Time Logic High Output 8 2 5 VCC -0.3V Logic Low Output 0.3 Hysteresis 40 V 5pF Load Can sink/source 1mA and maintain these logic levels. Can sink/source 1mA and maintain these logic levels. mV Power Down Control Logical Controls “ON” Logical Controls “OFF” Control Input Impedance Turn on Time 10-46 VCC -0.3V 0.3 >1 10 13 V V MΩ ms Voltage supplied to the input Voltage supplied to the input With recommended DC feedback cap (270nF) Rev A4 010820 RF2670 Parameter Specification Min. Typ. Max. Unit Condition Power Supply Voltage Current Consumption 2.7 3.0 3.6 V 13 17 mA VCC =3.0V; PD=High 1 µA VCC =3.0V; Sleep Mode, PD=Low IF AMPLIERS 10 Rev A4 010820 10-47 RF2670 IF AMPLIERS 10 Pin 1 2 3 4 5 Function IN IIN I+ GND2 DCFB I VCC2 6 7 8 9 GND3 IF OUT I VCC3 I DATA 10 11 RSSI I PD 12 13 GND1 BW SEL1 14 15 BW SEL2 Q DATA 16 17 18 19 20 RSSI Q VREF IF OUT Q VGC VCC1 21 22 23 24 DCFB Q GND1 IN Q+ IN Q- Description Interface Schematic Complementary input for the in-phase IF channel. Input for the in-phase IF channel. Ground for VCC2. DC feedback capacitor for in-phase channel. Power supply for VGA amplifier 3, differential to single-ended converter, and post filter. Ground for VCC3. Analog signal IF output for in-phase channel. Power supply for data amplifier. Logic-level data output for the in-phase channel. This is a digital output signal obtained from the output of a Schmitt trigger. Received signal strength indicator for the in-phase channel. Enable pin for the receiver circuits. PD >2.0V powers up all of the functions. PD<1.0V turns off all of the functions. Ground for VCC1 for both the in-phase and quadrature channels. Bandwidth select logic input. Pin 13 and pin 14 provide a two bit control word for the setting of the IF bandwidth. See Table1. Additional filtering should be used at the amplifiers to precisely control the 3dB bandwidth of the system. See design information details about differential input filters. See pin 13. Logic-level data output for the quadrature channel. This is a digital output signal obtained from the output of a Schmitt trigger. Received signal strength indicator for the quadrature channel. Gain control reference voltage. Analog signal IF output for quadrature channel. Gain control voltage. Power supply for bias circuits and VGA amplifiers for both the in-phase and quadrature channels. DC feedback capacitor for quadrature channel. Ground for VCC1 for both the in-phase and quadrature channels. Plus input for quadrature channel Minus input for quadrature channel Table 1: Bandwidth Selection Controls BWSEL1 BWSEL2 0 0 1 1 0 1 0 1 10-48 IF-3dB Frequency 1MHz 2MHz 4MHz 8MHz Rev A4 010820 RF2670 Differential Filter Design Information Butterworth Response L RS C1 C2 L RS RL RL 12 12 1 1 C1bw ⋅ --- ⋅ 10 C2bw ⋅ --- ⋅ 10 6 2 2 Lbw ⋅ RL ⋅ 10 C1 = -------------------------------------- ;C2 = -------------------------------------- ;L = ----------------------------------2 ⋅ π ⋅ fc ⋅ RL 2 ⋅ π ⋅ fc ⋅ RL 2 ⋅ π ⋅ fc C1bw = 5.1672 ;C2bw = 15.4554 ;Lbw = 0.1377 RS RS = 125 ;RL = 1000 ;------- = 0.125 RL 10 Differential LC Filter Component Values (Butterworth Response) IF AMPLIERS 100000 Component Value 10000 1000 C2 (pF) 100 C1 (pF) 10 L (µH) 1 1.E+05 1.E+06 1.E+07 Frequency Rev A4 010820 10-49 RF2670 Differential Filter Design Information (Cont.) Bessel Response L RS C1 C2 L RS RL RL 12 12 1 1 C1bw ⋅ --- ⋅ 10 C2bw ⋅ --- ⋅ 10 6 2 2 Lbw ⋅ RL ⋅ 10 C1 = -------------------------------------- ;C2 = -------------------------------------- ;L = ----------------------------------2 ⋅ π ⋅ fc ⋅ RL 2 ⋅ π ⋅ fc ⋅ RL 2 ⋅ π ⋅ fc C1bw = 2.9825 ;C2bw = 15.4697 ;Lbw = 0.0860 RS RS = 125 ;RL = 1000 ;------- = 0.125 RL 10 Differential LC Filter Component Values (Bessel Response) IF AMPLIERS 100000 Component Value 10000 1000 C2 (pF) 100 C1 (pF) 10 1 1.E+05 L (µH) 1.E+06 1.E+07 Frequency 10-50 Rev A4 010820 RF2670 Pin Out IN-I 1 24 IN-Q IN+I 2 23 IN+Q GND2 3 22 GND1 DCFBI 4 21 DCFBQ VCC2 5 20 VCC1 GND3 6 19 VGC IF OUT I 7 18 IF OUT Q VCC3 8 17 V REF I DATA 9 16 RSSI Q RSSI I 10 15 Q DATA 14 BW SEL2 GND1 12 13 BWSEL1 10 IF AMPLIERS PD 11 Rev A4 010820 10-51 RF2670 Evaluation Board Schematic (Download Bill of Materials from www.rfmd.com.) J1 I IN L1 10 µH 50 Ω µstrip C5 100 nF 50 Ω µstrip J4 Q IN T2 L2 10 µH C2 1 nF C6 100 nF DCFB I 1 IN I- IN Q- 24 2 IN I+ IN Q+ 23 3 GND2 GND1 22 VCC C3 1 nF C4 220 pF L4 10 µH C8 100 nF DCFB Q C10 220 nF DCFB Q 21 4 DCFB I C9 220 nF 5 VCC2 VCC1 20 6 GND3 VGC 19 VCC VGC 50 Ω µstrip VREF VREF 17 C11 47 nF 50 Ω µstrip RSSI Q 16 9 I DATA RSSI I C13 68 pF V IF EN 10 RSSI I Q DATA 15 11 V IF EN BW SEL2 14 12 GND1 BW SEL1 13 J5 IF OUT Q 50 Ω µstrip IF OUT Q 18 7 IF OUT I 8 VCC3 J3 I DATA L3 10 µH T1 C1 220 pF J2 IF OUT I C7 100 nF C12 68 pF RSSI Q J6 Q DATA 50 Ω µstrip BW SEL2 BW SEL1 2670400- P1 P1-1 10 IF AMPLIERS L1-L4 and C1-C4 make two LPFs. The fc of the RF2670 is variable; therefore the L and C components must be variable. The following table gives recommended component values ("std" indicates standard eval board value). Desired BW BW1, BW2 C1, C4 (pF) C2, C3 (pF) L1-L4 (µH) 700 kHz 0 0 330 1800 P1-3 P4-1 0 1 220 (std) 1000 (std) 10 2.8 MHz 1 0 100 470 4.7 P4-3 7.0 MHz 1 1 33 180 V IF EN 2 GND 3 DCFB I P2-3 1 DCFB Q P5-1 2 GND 3 VREF P2-1 P4 22 1.4 MHz P2 1 1 RSSI Q 2 GND 3 RSSI I P5 P5-3 1 BW SEL2 2 GND 3 BW SEL1 2.2 P3 P3-1 C21 100 pF C22 10 nF C23 100 pF C24 10 nF C25 100 pF C26 10 nF C27 10 µF P3-3 10-52 1 VCC 2 GND 3 VGC Rev A4 010820 RF2670 Evaluation Board Layout Board Size 3.0” x 2.0” IF AMPLIERS 10 Rev A4 010820 10-53 RF2670 RF2670 IF Bandwidth Response 65.0 55.0 45.0 Gain (dB) 35.0 25.0 15.0 BW_SEL (0-0) BW_SEL (0-1) 5.0 BW_SEL (1-0) BW_SEL (1-1) -5.0 -15.0 -25.0 -35.0 0.1 1.0 10.0 100.0 IF Frequency (MHz) IF AMPLIERS 10 10-54 Rev A4 010820 RF2670 IIP3 versus Voltage Gain Noise Figure versus Voltage Gain (Non-Matched Input Z) 40.0 10.0 -40°C -40°C +25°C 0.0 +25°C 35.0 +100°C +100°C -10.0 30.0 Noise Figure (dB) IP3 (dB) -20.0 -30.0 -40.0 -50.0 25.0 20.0 15.0 10.0 -60.0 5.0 -70.0 -80.0 0.0 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 Voltage Gain (dB) 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 Voltage Gain (dB) Voltage Gain versus Gain Control Voltage 90.0 -40°C 80.0 +25°C +100°C Voltage Gain (dB) 70.0 60.0 50.0 40.0 10 30.0 IF AMPLIERS 20.0 10.0 0.0 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 Gain Control Voltage (V) Rev A4 010820 10-55 RF2670 IF AMPLIERS 10 10-56 Rev A4 010820