Asahi Kasei Microdevices Corporation, (AKM), launches a fractional-N PLL IC, the AK1574.  A built-in VCO saves space, has low-phase noise, and low-power consumption.  Uses include two-way radios in the VCO configuration with a variable capacitance diode and a winding coil.  This product is targeting professional, portable radio equipment.

Features

 

。 Easy to Modulate the Frequency of an Analog Voice Signal Input

 

By integrating a dedicated A/D converter, (ADC), frequency modulation of analog voice signal inputs are accomplished.  This makes it easy to replace a VCO built-in PLL without changing the design considerably from the conventional architecture, (inputting the analog voice signal directly to the VCO without transmitting via a quadrature modulator).

。 Low Phase Noise and Low Power Consumption

The AK1574 is optimized for narrow band radio below 1GHz.  While achieving low normalized phase noise of -221dBc/Hz, it operates with power consumption of 90mW, (3V/single output), at -6dBm output.

Lock-up time, which takes several ms to several tens of ms for a general VCO with a variable capacitance diode and winding coil configuration, is completed in less than 1ms on the AK1574.  The intermittent operation of the PLL and VCO can reduce the power consumption of the system.

 

Product Name	AK1574	AK1573/B/C (3 Chip Options)
Method	Fractional-N	Integer-N
Operating Frequency	46.875 to 1682.5MHz	30 to 3000MHz
Consumption Current	30mA at 3V, 520.1MHz, -6dBm Output (Single Output)	33mA at 3V, 1600MHz, -5dBm Output
Power Supply /Temperature Range	2.7 to 3.45V (IOVDD: 1.7V Operation) / -40 to +85°C	2.7 to 3.3V / -40 to +85°C
Normalized Phase Noise	-221dBc/Hz (Fractional-N in operation)	-223dBc/Hz
In-band Phase Noise	-125dBc/Hz at 12.5kHz Offset, 420MHz Output, PFD Frequency =50.4MHz	Not availabe
Modulation Function	· Support analog voice signal inputs (integrated ADC) · Various Digital I/F: I2S, Left justified, SPI	Not availabe
23-bit ΔΣ Modulator	10Hz or less frequency resolution	Not availabe
Variable Output Buffer of Output Current	-12 to +6dBm Output (Single Output)	-12 to +6dBm Output
Reference Clock Multiplying/Dividing Circuit	Reduce Integer Boundary Spurious (IBS)	Not availabe
Reference Clock Divider Output Function	Common System Clock	Not availabe
REFCKIN Frequency	10 to 60MHz	10 to 300MHz
Package	36-pin QFN (5 ×5 × 0.75mm, 0.4mm pitch)	24-pin QFN (4 ×4 × 0.75mm, 0.5mm pitch

 
source：http://www.akm.com/