LT5546 40MHz to 500MHz VGA and I/Q Demodulator with 17MHz Baseband Bandwidth FEATURES DESCRIPTIO 17MHz I/Q Lowpass Output Noise Filters The LT 5546 is a 40MHz to 500MHz monolithic integrated Wide Range 1.8V to 5.25V Supply Voltage quadrature demodulator with variable gain amplifier (VGA) Frequency Range: 40MHz to 500MHz and 17MHz I/Q baseband bandwidth designed for low volt- THD < 0.14% (57dBc) age operation. It supports standards that use a linear modu- at 800mV Differential Output Level P-P lation format. The chip consists of a VGA, quadrature down- IF Overload Detector converting mixers and 17MHz lowpass noise filters (LPF). Log Linear Gain Control Range: 7dB to 56dB The LO port consists of a divide-by-two stage and LO Baseband I/Q Amplitude Imbalance: 0.2dB buffers. The IC provides all building blocks for IF down- Baseband I/Q Phase Imbalance: 0.6 conversion to I and Q baseband signals with a single 7.8dB Noise Figure at Max Gain supply voltage of 1.8V to 5.25V. The VGA gain has a linear- Input IP3 at Low Gain: 1dBm in-dB relationship to the control input voltage. Hard-clip- Low Supply Current: 24mA ping amplifiers at the mixer outputs reduce the recovery Low Delay Shift Over Gain Control Range: 2ps/dB time from a signal overload condition. The lowpass filters Outputs Biased Up While in Standby 16-Lead QFN 4mm 4mm Package with Exposed Pad reduce the out-of-band noise and spurious frequency components. The 3dB corner frequency of the noise U filters is approximately 17MHz and has a first order roll- APPLICATIO S off. The standby mode provides reduced supply current and fast transient response into the normal operating mode GPS IF Receivers when the I/Q outputs are AC-coupled to a baseband chip. Satellite IF Receivers VHF/UHF Receivers , LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Wireless Local Loop TYPICAL APPLICATIO Total Harmonic Distortion vs 1.8V IF Input Level at 1.8V Supply 280MHz C2 C1 IF INPUT + 25 1F 1nF IF L1 f = 280MHz IF, 1 15nH f = 280.1MHz IF, 2 30 V CC C3 f = 570MHz 2xLO + I 10pF OUT 800mV DIFFERENTIAL OUT P-P 35 L2 IF 15nH I OUT 40 IF DET V CTRL C3 GAIN CONTROL 45 + 1.8pF 2xLO + Q OUT 50 2xLO C4 L3 560MHz 2 3.3pF Q 39nH OUT INPUT 55 2xLO LT5546 EN STBY GND 60 C5 60 50 40 30 20 10 5546 TA01 3.3pF ENABLE STANDBY IF INPUT POWER EACH TONE (dBm) 5546 TA01b 5546fa 1 THD (dBc) U ULT5546 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) TOP VIEW ORDER PART Supply Voltage ....................................................... 5.5V NUMBER + Differential Voltage Between 2xLO and 2xLO .......... 4V 16 15 14 13 + IF , IF ............................................. 500mV to 500mV GND 1 12 STBY LT5546EUF + + I , I , Q , Q ..................V 1.8V to V + + OUT OUT OUT OUT CC CC IF 2 11 2xLO 17 Operating Ambient Temperature IF 3 10 2xLO (Note 2) ...................................................40C to 85C GND 4 9 EN 5 6 7 8 Storage Temperature Range ..................65C to 125C UF PART MARKING Voltage on Any Pin Not to Exceed ........................ 500mV to V + 500mV 5546 CC UF PACKAGE 16-LEAD (4mm 4mm) PLASTIC QFN T = 125C, = 37C/W JMAX JA EXPOSED PAD IS GND (PIN 17) (MUST BE SOLDERED TO PCB) Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS V = 3V, f = 570MHz, P = 5dBm (Note 5), f = 284MHz, CC 2xLO 2xLO IF P = 30dBm, I and Q outputs 800mV into 4k differential load, T = 25C, EN = V , STBY = V , unless otherwise noted. (Note 3) IF P-P A CC CC SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS IF Input f Frequency Range 40 to 500 MHz IF Nominal Input Level R = 200 Differential 76 to 19 dBm SOURCE + Input Impedance IF , IF to GND, EN = V 100//1.2pF CC + IF , IF to GND, EN = GND 1pF NF Noise Figure at Max Gain V = 1.7V 7.8 dB CTRL G Min Gain (Note 4) V = 0.2V 1.6 6 dB L CTRL G Max Gain (Note 4) V = 1.7V 49 56 dB H CTRL IIP3 Input IP3, Min Gain P = 22.5dBm (Note 7) 1 dBm IF Input IP3, Max Gain P = 75dBm (Note 7) 49 dBm IF IIP2 Input IP2, Min Gain V = 0.2V (Note 9) 36 dBm CTRL Input IP2, Max Gain V = 1.7V (Note 9) 25 dBm CTRL Demodulator I/Q Output Nominal Voltage Swing (Note 6) 0.8 V P-P Clipping Level (Note 6) 1.47 V P-P DC Common Mode Voltage V 1.19 V CC I/Q Amplitude Imbalance (Note 8) 0.14 0.6 dB I/Q Phase Imbalance (Note 8) 0.6 3 Deg DC Offset (Notes 6, 8) 21 mV Output Driving Capability Single Ended, C 10pF 2 1.5 k LOAD r Small-Signal Output Impedance (Note 6) 180 o STBY to Turn-On Delay 0.3 s I/Q Output 1dB Compression 10 dBm I/Q Output IM3 P = 25.5dBm, 280MHz 49 dBc IF, 1 P = 25.5dBm, 280.1MHz (Note 7) IF, 2 5546fa 2 + V I CC OUT V I CTRL OUT + IF DET Q OUT V Q CC OUT U WWW