UBA2021_4 © NXP B.V. 2008. All rights reserved.
Product data sheet Rev. 04 — 25 July 2008 7 of 16
NXP Semiconductors
UBA2021
630 V driver IC for CFL and TL lamps
7.12 Frequency and change in frequency
At any point in time during oscillation, the circuit will operate between f
B
and f
start
. Any
change in frequency will be gradual, no steps in frequency will occur. Changes in
frequency caused by a change in voltage at the CI-pin show a rather constant ∆f/∆t over
the entire frequency range. The following rates are realized (at a frequency of 85 kHz and
with a 100 nF capacitor connected to the PCI-pin):
• For any increase in frequency: ∆f/∆t is between 15 kHz/ms and 37.5 kHz/ms.
• During preheat and normal operation: ∆f/∆t for a decrease in frequency is between
−6 kHz/ms and −15 kHz/ms.
• During the ignition phase: ∆f/∆t for a decrease in frequency is between
−150 Hz/ms and −375 Hz/ms.
7.13 Ground pins
The PGND-pin is the ground reference of the IC with respect to the application. As an
exception the SGND-pin provides a local ground reference for the components connected
to the CP-pin, CI-pin, RREF-pin and thee CF-pin. For this purpose the PGND-pin and
SGND-pin are short circuited internally. External connection of the PGND-pin and the
SGND-pin is not preferred. The sum of currents flowing out of the CP-pin, CI-pin,
RREF-pin, CF-pin and the SGND-pin must remain zero at all time.
7.14 Charge coupling
Due to parasitic capacitive coupling to the high voltage circuitry, all pins are burdened with
a repetitive charge injection. Given the typical application in Figure 7, the RREF-pin and
the CF-pin are sensitive to this charge injection. For the rating Q
couple
a safe functional
operation of the IC is guaranteed, independent of the current level. Charge coupling at
current levels below 50 mA will not interfere with the accuracy of the V
RS(cap)
and V
RS(ctrl)
levels. Charge coupling at current levels below 20 mA will not interfere with the accuracy
of any parameter.
8. Limiting values
Table 5. Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134). All voltages referenced to
ground.
Symbol Parameter Conditions Min Max Unit
V
FS
high side floating supply
voltage
operating - 570 V
t ≤ 0.5 s - 630 V
I
VS(clamp)
clamp current - 35 mA
V
RS
input voltage pin RS −2.5 +2.5 V
transient of 50 ns −15 +2.5 V
SR slew rate at pins S1, G1
and FS (with respect to
ground)
−4 +4 V/ns
P power dissipation - 500 mW
T
amb
ambient temperature −40 +150 °C
T
j
junction temperature −40 +150 °C
