Data Sheet
AD9510
Rev. B | Page 53 of 56
POWER SUPPLY
The AD9510 requires a 3.3 V ± 5% power supply for VS. The from th
e AD9510 with the power supply voltage within this
range. The absolute maximum range of 0.3 V +3.6 V, with
respect to GND, must never be exceeded on the VS pin.
Follow good engineering practice in the layout of power supply
traces and the ground plane of the printed circuit board (PCB).
Bypass the power supply on the PCB with adequate capacitance
(>10 F). Bypass t
he AD9510 with adequate capacitors (0.1 F)
at all power pins as close as possible to the part. The layout of the
AD9510-VCO/PCBZ) is a good example.
T
he AD9510 is a complex part that is programmed for its desired
operating configuration by on-chip registers. These registers are
not maintained over a shutdown of external power. This means
that the registers can lose their programmed values if VS is lost
long enough for the internal voltages to collapse. Careful bypassing
protects the part from memory loss under normal conditions.
Nonetheless, it is important that the VS power supply not become
intermittent, or the
AD9510 risks losing its programming.
The internal bias currents of the AD9510 are set by the RSET and CPRSET resistors. These resistors must be as close as possible to
(RSET = 4.12 k and CPRSET = 5.1 k). These values are standard
1% resistor values, and are readily obtainable. The bias currents
set by these resistors determine the logic levels and operating
conditions of the internal blocks of t
he AD9510. The performance
resistor values are used.
The VCP pin is the supply pin for the charge pump (CP). The
voltage at this pin (VCP) can be from VS up to 5.5 V, as required
to match the tuning voltage range of a specific VCO/VCXO.
This voltage must never exceed the absolute maximum of 6 V.
Additionally, never allow VCP to be less than 0.3 V below VS or
GND, whichever is lower.
The exposed metal paddle on th
e AD9510 package is an electrical
connection, as well as a thermal enhancement. For the device
to function properly, the paddle must be properly attached to
ground (GND). The PCB acts as a heat sink for th
e AD9510;therefore, this GND connection must provide a good thermal path
to a larger dissipation area, such as a ground plane on the PCB.
or
AD9510-VCO/PCBZ) for a good example.
POWER MANAGEMENT
The power usage of th
e AD9510 can be managed to use only the
power required for the functions being used. Unused features
and circuitry can be powered down to save power. The following
circuit blocks can be powered down, or are powered down when
The PLL section can be powered down if not needed.
Any of the dividers are powered down when bypassed—
equivalent to divide-by-one.
The adjustable delay blocks on OUT5 and OUT6 are
powered down when not selected.
Any output can be powered down. However, LVPECL
outputs have both a safe and an off condition. When the
LVPECL output is terminated, use only the safe shutdown
to protect the LVPECL output devices. This still consumes
some power.
The entire distribution section can be powered down when
not needed.
Powering down a functional block does not cause the program-
ming information for that block (in the registers) to be lost.
This means that blocks can be powered on and off without
otherwise having to reprogram the
AD9510. However, synchro-
nization is lost. A SYNC must be issued to resynchronize (see