U2794B

Features • Supply Voltage 5V • Very Low Power Consumption 125 mW • Very Good Image Rejection By Means of Phase Control Loop for Precise 90° Phase • • • • • • Shifting Duty-cycle Regeneration for Single-ended LO Input Signal Low LO Input Level –10 dBm LO Frequency from 70 MHz to 1 GHz Power-down Mode 25 dB Gain Control Very Low I/Q Output DC Offset Voltage Typically < 5 mV Benefits • Low Current Consumption • Easy to Implement • Perfect Performance for Large Variety of Wireless Applications 1000-MHz Quadrature Demodulator U2794B 1. Description The silicon monolithic integrated circuit U2794B is a quadrature demodulator manufactured using Atmel ®’s advanced UHF technology. This demodulator features a frequency range from 70 MHz to 1000 MHz, low current consumption, selectable gain, power-down mode, and adjustment-free handling. The IC is suitable for direct conversion and image rejection applications in digital radio systems up to 1 GHz such as cellular radios, cordless telephones, cable TV, and satellite TV systems. Figure 1-1. VS 5,6 Block Diagram PU 14 IIX 4 II 3 1 2 IX OUTPUT I Power down RFin 7 8 90°Control loop 0° 90° Frequency doubler Duty cycle 15 LO regenerator 17 13 PC 12 19 20 PCX Q OUTPUT QX 11 16,18 10 9 GC GND QQX QQ 4653F–CELL–11/08 2. Pin Configuration Figure 2-1. Pinning SSO20 IX I II IIX V S VS RFin RFXin QQ QQX 1 2 3 4 5 6 7 8 9 10 20 QX 19 18 17 16 15 Q GND LOin GND LOXin 14 PU 13 PC 12 PCX 11 GC Table 2-1. Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Pin Description Symbol IX I II IIX VS VS RFin RFXin QQ QQX GC PCX PC PU LOXin GND LOin GND Q QX Function IX output I output II lowpass filter I IIX lowpass filter I Supply voltage Supply voltage RF input RFX input QQ lowpass filter Q QQX lowpass filter Q GC gain control PCX phase control PC phase control PU power up LOX input Ground LO input Ground Q output QX output 2 U2794B 4653F–CELL–11/08 U2794B 3. Absolute Maximum Ratings Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Parameters Supply voltage Input voltage Junction temperature Storage-temperature range Symbol VS Vi Tj Tstg Value 6 0 to VS +125 –55 to +125 Unit V V °C °C 4. Thermal Resistance Parameters Junction ambient SSO20 Symbol RthJA Value 140 Unit K/W 5. Operating Range Parameters Supply-voltage range Ambient-temperature range Symbol VS Tamb Value 4.75 to 5.25 –40 to +85 Unit V °C 3 4653F–CELL–11/08 6. Electrical Characteristics Test conditions (unless otherwise specified); VS = 5V, Tamb = 25°C, referred to test circuit System impedance ZO = 50Ω, fiLO = 950 MHz, PiLO = –10 dBm No. 1.1 1.2 2 2.1 3 3.1 3.2 4 4.1 4.2 4.3 4.4 4.5 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Notes: Parameters Supply-voltage range Supply current Power-down Mode “OFF” mode supply current Switch Voltage “Power ON” “Power DOWN” LO Input, LOin Frequency range Input level Input impedance Voltage standing wave ratio Duty-cycle range RF Input, RFin Noise figure (DSB) symmetrical output Frequency range –1 dB input compression point Second order IIP Third order IIP LO leakage Input impedance at 950 MHz(3) at 100 MHz fiRF = fiLO ±BWYQ High gain Low gain (4) (2) Test Conditions Pin 5, 6 5, 6 Symbol VS IS Min. 4.75 22 Typ. 30 ≤1 20 Max. 5.25 35 Unit V mA µA µA V Type* A A B D D D D D D D D VPU ≤ 0.5V VPU = 1.0 V(1) 14, 5 6 14 14 17 17 17 17 17 ISPU VPON VPOFF fiLO PiLO ZiLO VSWRLO DCRLO 4 1 70 –12 –10 50 1.2 0.4 12 10 40 –8 +3.5 35 +3 +13 ≤ –60 ≤ –55 500II0.8 1030 2 0.6 1000 –5 V MHz dBm Ω See Figure 6-10 See Figure 6-3 7, 8 7, 8 7, 8 7, 8 7, 8 7, 8 7, 8 NF fiRF P1dBHG P1dBLG IIP2HG IIP3HG IIP3LG LOL ZiRF dB MHz dBm dBm dBm dBm ΩIIpF D D D D D D D High gain Low gain Symmetric input Asymmetric input see Figure 6-10 *) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter 1. During power-down status a load circuitry with DC-isolation to GND is assumed, otherwise a current of I ≈ (VS –0.8V)/RI has to be added to the above power-down current for each output I, IX, Q, QX. 2. The required LO-Level is a function of the LO frequency (see Figure 6-6). 3. Measured with input matching. For 950 MHz, the optional transmission line T3 at the RF input may be used for this purpose. Noise figure measurements without using the differential output signal result in a worse noise figure. 4. Using pins 7 and 8 as a symmetric RF input, the second-order IIP can be improved. 5. Due to test board parasitics, this bandwidth may be reduced and not be equal for I, IX, Q, QX. If symmetry and full bandwidth is required, the lowpass pins 3, 4 and 9, 10 should be isolated from the board. the bandwidth of the I/Q outputs can be increased further by using a resistor between pins 3, 4, 9 and 10. These resistors shunt the internal loads of RI ~ 5.4 kΩ. The decrease in gain here has to be considered. 6. The internal current of the output emitter followers is 0.6 mA. This reduces the undistorted output voltage swing at a 50Ω load to approximately 30 mV. For low signal distortion the load impedance should be RI ≥ 5 kΩ. 7. Referred to the level of the output vector I +Q 2 2 8. The low-gain status is achieved with an open or high-ohmic pin 11. A recommended application circuit for switching between high and low gain status is shown in Figure 6-1. 4 U2794B 4653F–CELL–11/08 U2794B 6. Electrical Characteristics (Continued) Test conditions (unless otherwise specified); VS = 5V, Tamb = 25°C, referred to test circuit System impedance ZO = 50Ω, fiLO = 950 MHz, PiLO = –10 dBm No. 6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 7 7.1 7.2 7.3 7.4 7.5 7.6 7.7 Notes: Parameters 3-dB bandwidth w/o external C I/Q amplitude error I/Q phase error I/Q maximum output swing DC output voltage DC output offset voltage Output impedance Gain Control, GC Control range power Gain high Gain low Switch Voltage “Gain high” “Gain low” Settling Time, ST Power “OFF” - “ON” Power “ON” - “OFF” TSON TSOFF