Description
The 8V19N472 is a fully integrated FemtoClock NG Jitter Attenuator
and Clock Synthesizer designed as a high-performance clock
solution for conditioning and frequency/phase management of
wireless base station radio equipment boards. The device is
optimized to deliver excellent phase noise performance as required
in GSM, WCDMA, LTE, and LTE-A radio board implementations.
A two-stage PLL architecture supports both jitter attenuation and
frequency multiplication. The first stage PLL is the jitter attenuator
and uses an external VCXO for best possible phase noise
characteristics. The second stage PLL locks on the VCXO-PLL
output signal and synthesizes the target frequency. This PLL has two
VCO circuits at 2949.12MHz and 2400–2500MHz, respectively, for
enhanced frequency flexibility.
The device generates the output clock signals from the selected
VCO by frequency division. Five independent frequency dividers are
available, four support integer-divider ratios and one integer as well
as fractional-divider ratios. Delay circuits can be used for achieving
alignment and controlled phase delay between clock signals. The
two redundant inputs are monitored for activity. Four selectable clock
switching modes are provided to handle clock input failure scenarios.
Auto-lock, individually programmable output frequency dividers, and
phase adjustment capabilities are added for flexibility.
The 8V19N472 is configured through an SPI interface and reports
lock and signal loss status in internal registers and via a lock detect
(LOCK) output. Internal status bit changes can also be reported via
the nINT output. The device is ideal for driving converter circuits in
wireless infrastructure, radar/imaging, and instrumentation/medical
applications. The device is a member of the high-performance clock
family from IDT.

Features
▪ High-performance clock RF-PLL
▪ Optimized for low phase noise: <-150dBc/Hz (1MHz offset;
245.76MHz clock)
▪ Dual-PLL architecture
— 1st-PLL stage with external VCXO for clock jitter attenuation
— 2nd-PLL stage with internal FemtoClockNG PLL at selectable
2949.12MHz and MHz (2400–2500MHz) VCO frequency
▪ Six output banks with a total of 12 outputs, organized in:
— Two clock banks with one integer frequency divider and three
differential outputs
— Two clock banks with one integer frequency divider and two
differential outputs
— One clock bank with one fractional output divider and one
differential output
— One VCXO-PLL output bank with one selectable LVDS/two
LVCMOS outputs
▪ Supported clock output frequencies include:
— From VCO-0: 2949.12, 1474.56, 983.04, 491.52, 368.64,
122.88MHz
— From VCO-1: 2457.6, 1228.8, 614.4, 307.2, 153.6, 76.8MHz
— From the fractional output divider: 80 – 300MHz
▪ Clock channels with integer output divider contain a phase delay
circuit with 512 steps of half of the selected VCO period
▪ Low-power LVPECL/LVDS outputs support configurable signal
amplitude, DC and AC coupling and LVPECL, LVDS line
terminations techniques
▪ Redundant input clock architecture
— Two inputs with an individual input signal monitor
— Digital holdover
— Manual and automatic clock selection
— Hitless switching
▪ Status monitoring and fault reporting
— Input signal status
— Hold-over and reference loss status
— Lock status with one status pin
— Maskable status interrupt pin
▪ Voltage supply:
— Device core supply voltage: 3.3V
— Output supply voltage: 3.3V, 2.5V, or 1.8V
— SPI control I/O voltage: 1.8V or 3.3V (selectable),
3.3V tolerant inputs when set to 1.8V
▪ Package: 81-FPBGA (8  8mm, 0.8 mm ball pitch)
▪ Temperature range: -40°C to +85°C