Datasheet

UBA2071_A_1 © NXP B.V. 2008. All rights reserved.
Product data sheet Rev. 01 — 23 June 2008 5 of 35
NXP Semiconductors
UBA2071; UBA2071A
Half bridge control IC for CCFL backlighting
7. Pinning information
7.1 Pinning
7.2 Pin description
Fig 2. Pin assignment SO24 and SSOP24 package (top view)
UBA2071
IFB GH
CIFB FS
VFB SH
CVFB n.c.
CSWP n.c.
CT n.c.
CF GL
IREF PGND
CPWM VDD
SGND EN
COMM PWMA
NONFAULT PWMD
014aaa099
1
2
3
4
5
6
7
8
9
10
11
12
14
13
16
15
18
17
20
19
22
21
24
23
Table 3. Pin description
Symbol Pin Description Function
IFB 1 current feedback input. Input signal for the lamp current control loop. Should be connected to a
voltage proportional to the lamp current.
CIFB 2 current regulation
capacitor.
A capacitor must be connected between this pin and the signal ground. It
sets the time constant of the lamp current control loop.
VFB 3 voltage feedback input Input signal for the voltage control loop. Should be connected to a voltage
proportional to the transformer output voltage.
CVFB 4 voltage regulation
capacitor
A capacitor must be connected between this pin and the signal ground. It
sets the time constant of the voltage control loop.
CSWP 5 frequency sweep
capacitor
A capacitor must be connected between this pin and the signal ground. It
sets the time in which the HF frequency is swept up from regulation level to
the maximum frequency and back during PWM dimming.
CT 6 fault timing capacitor A capacitor must be connected between this pin and the signal ground. It
sets the time that a fault condition is allowed before the IC shuts down itself.
CF 7 HF-oscillator timing
capacitor
A capacitor must be connected between this pin and the signal ground. It
sets the minimum switching frequency of the half bridge.
IREF 8 reference current output A 33 kΩ resistor must be connected between this pin and the signal ground.
The IC uses it to make accurate internal currents.
CPWM 9 PWM timing capacitor If a capacitor is connected between this pin and the signal ground, it sets the
frequency of the PWM oscillator.
If this pin is connected to signal ground the internal PWM oscillator is
disabled.
SGND 10 signal ground
COMM 11 master / slave
communication
Via this pin the IC can communicate with a dedicated slave device.