Datasheet MAX1472 (Maxim) - 8

300MHz-to-450MHz Low-Power, Crystal-Based ASK Transmitter Layout Considerations Functional Diagram
A properly designed PC board is an essential part of any RF/microwave circuit. On the PA output, use con- trolled-impedance lines and keep them as short as possible to minimize losses and radiation. At high fre- DATA AND ENABLE quencies, trace lengths that are on the order of λ/10 or GATE longer can act as antennas. VDD Keeping the traces short also reduces parasitic induc-
MAX1472
tance. Generally, 1in of PC board trace adds about MAX1472 PA PAOUT 20nH of parasitic inductance. The parasitic inductance can have a dramatic effect on the effective inductance. For example, a 0.5in trace connecting a 100nH induc- PAGND tor adds an extra 10nH of inductance, or 10%. LOCK DETECT 32 x PLL To reduce the parasitic inductance, use wider traces GND and a solid ground or power plane below the signal XTAL1 CRYSTAL- traces. Using a solid ground plane can reduce the par- OSCILLATOR asitic inductance from approximately 20nH/in to 7nH/in. XTAL2 DRIVER Also, use low-inductance connections to ground on all GND pins, and place decoupling capacitors close to all VDD connections.
Chip Information Package Information
PROCESS: CMOS For the latest package outline information and land patterns (footprints), go to
www.maxim-ic.com/packages
. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PACKAGE PACKAGE LAND OUTLINE NO. TYPE CODE PATTERN NO.
8 SOT23 K8SN+1
21-0078 90-0176 8