TDA6650TT Datasheet, PDF (37/55 Pages) NXP Semiconductors – 5 V mixer/oscillator and low noise PLL synthesizer for hybrid terrestrial tuner (digital and analog)

Philips Semiconductors
5 V mixer/oscillator and low noise PLL synthesizer
for hybrid terrestrial tuner (digital and analog)
Product specification
TDA6650TT;
TDA6651TT
The TDA6650TT, TDA6651TT PLL loop stability is
guaranteed in the configuration of Figs. 27, 28, 29 and 30.
In this configuration, the external supply source is 30 V
minimum, the pull-up resistor R19, is 15 kΩ and all of the
local oscillators are aligned to operate at a maximum
tuning voltage of 26 V. If the configuration is changed,
there might be an impact on the loop stability.
For any other configurations, a stability analysis must be
performed. The conventional PLL AC model (cf. SIMPATA
Philips software) used for the stability analysis, is valid
provided the external source (DC supply source or
DC-to-DC converter) is able to deliver a minimum current
that is equal to the charge pump current in use.
The delivered current can be simply calculated with the
following formula:
I_delivered
=


V-----_D---RC----p-–_{--u---V----T-}
> I_CP
Where
I_delivered is the delivered current
V_DC is the supply source voltage or DC-to-DC converter
output voltage
V_T is the tuning voltage
R_pu is the pull-up resistor between the DC supply source
(or the DC-to-DC converter output) and the tuning line
(R19 in Figs. 27 to 30)
I_CP is the charge pump current in use.
2004 Mar 22
37