500MHz to 2500MHzVCO Buffer AmplifiersMAX2472/MAX2473Pin DescriptionPINNAMEFUNCTIONMAX2472MAX2473 Open-Collector Buffer Output 1. Connect to V 1 — CC via a resistor or OUT1 inductor/choke. AC-coupling to the output is required. Open-Collector Buffer Output. Connect to V — 1 CC via a resistor or OUT inductor/choke. AC-coupling to the output is required. RF Ground. Connect to the ground plane as close to the IC as possible to 2, 5 2, 5 GND minimize trace inductance. Open-Collector Buffer Output 2. Connect to V 3 — CC via a resistor or OUT2 inductor/choke. AC-coupling to the output is required. Bias Resistor Connection. Connect a resistor from BIAS to GND to set the — 3 BIAS output stage bias current and gain. To choose RBIAS, refer to the Typical Operating Characteristics for the MAX2473. 4 4 IN High-Impedance Input to the Buffer Amplifier 6 6 VCC Supply Voltage Input: +2.7V < VCC < +5.5V Table 1. Output Matching ComponentsOPERATINGFREQUENCYLMATCHCMATCH(MHz) 22nH 1.5pF 600 Coilcraft 0603HS-22NTJBC Murata GRM39COG1R5B50V 12nH 1pF 900 Coilcraft 0603HS-12NTJBC Murata GRM39COG1R0B50V 2.2nH 1pF 1900 Murata LQG11AZN2500 Murata GRM39COG1R0B50V 1.2nH 1pF 2400 Murata LQG11AINZS00 Murata GRM39COG1R0B50V Detailed Description two separate open-collector output stages. The MAX2473 features a two-stage wideband architecture The MAX2472/MAX2473 are ideal replacements for dis- with a high-input-impedance common-emitter amplifier crete solutions where a VCO output must drive more followed by one open-collector output stage, with the than one input, especially where high reverse isolation added feature of output power control. Using values for and low supply currents are mandatory. The MAX2472 R features a two-stage wideband architecture with a high- BIAS from 11kΩ to 23kΩ allows the output power of the MAX2473 to range from -2dBm to -10dBm. input-impedance common-emitter amplifier followed by _______________________________________________________________________________________9