NXP Semiconductors TFA9810 - Manual (Page 6)

TFA9810_3 © NXP B.V. 2008. All rights reserved.
Product data sheet Rev. 03 — 20 February 2008 6 of 29
NXP Semiconductors
TFA9810
Audio amplifier 2 x 12 W
In SLEEP mode the TFA9810 is not biased and has a very low supply current.
When the TFA9810 is set to OPERATING mode the device is started via the start-up
sequence, which provides a pop-free start-up behavior. After start-up the reference
voltages STAB are present and the outputs start switching.
8.3 Input comparators
The input stages have a differential input and are optimized for low noise and low offset.
This results in maximum flexibility in the application.
8.3.1 Operating in self-oscillating configuration
The inputs (IN1P, IN1N, IN2P, IN2N) of the comparators are internally set to a voltage level
of 0.5V
P
, but only during the start-up sequence. In operating mode the inputs are
high-ohmic.
8.3.2 Operating in open-loop configuration
No internal voltages are applied to the inputs. The input pins (IN1P, IN1N, IN2P, IN2N) are
pulled down to V
SSA
level by internal resistors.
8.4 Diagnostic
The DIAG output is an open-drain output. The maximum current is 2 mA. Whenever one
of the protections is triggered the DIAG output is activated low. The DIAG output refers to
V
SSD
.
8.5 Protections
Overtemperature, overcurrent, overvoltage, undervoltage, overdissipation sensors, and
window protection are included in the TFA9810. When one of these sensors exceeds its
threshold level either the output power stage is switched off and the outputs (OUT1N,
OUT1P, OUT2N, OUT2P) become floating, or the TFA9810 shuts down and starts up
immediately.
• OverTemperature Protection (OTP)
If the junction temperature (T
j
) exceeds a threshold level of about 150
°
C then the
outputs become floating. The device will start switching again after 5
µ
s and when the
temperature is below 150
°
C. This is thermal limitation without audible interruptions.
• OverCurrent Protection (OCP)
If the output current exceeds the maximum output current threshold level the output
becomes floating. The device will start switching again after 5
µ
s. This is current
limitation without audible interruptions.
Table 5. Start-up
Interfacing
ENABLE [V] Mode
ENABLE < 0.8 V SLEEP
ENABLE > 3 V OPERATING