AK1544

[AK1544] AK1544 1300MHz Integer-N Frequency Synthesizer 1. Overview Consisting a highly accurate charge pump that supports current adjustment in 9 steps, a reference divider, a programmable divider and a dual-modulus prescaler (P/P+1), the AK1544 provides high performance, low consumption current and small footprint for a wide range of frequency conversions. This synthesizer also has two general-purpose output pins which allow it to be used to control the RF front end. An ideal Phase Locked Loop (PLL) can be achieved by combining the AK1544 with the external loop filter and VCO (Voltage Controlled Oscillator). Access to the registers is controlled via a 3-wire serial interface. The operating supply voltage is from 2.7V to 5.5V; and the supply voltage for the charge pump and that for the serial interface can be driven separately. 2. Features   Operating frequency: Programmable charge pump current: 400 to 1300MHz 160 to 2530A typical The charge pump current can be changed in 9 steps, and the current range can be adjusted by the external resistance. Two current settings can be specified with the register and switched over from one to another using the timer.     Supply Voltage: Separate power supply for the charge pump: On-chip power-saving features On-chip lock detection feature of PLL: 2.7 to 5.5 V (PVDD pin) PVDD to 5.5V (CPVDD pin) Direct output to the PFD (Phase frequency detector) or digital filtering output can be selected.  General-purpose output: It h...