apa2058 Anpec Electronics Corporation, apa2058 Datasheet - Page 22

• Manufacturer Part Number: apa2058
• Description: 2.4w Stereo Fully Differential Audio Power Amplifier With Stereo Class Ab Cap-free Headphone Driver And Ldo
• Manufacturer: Anpec Electronics Corporation

Function Description (Cont.)
APA2058
Over-Current Protection (OCP) (Cont.)
addition, it has an over voltage protection to avoid over
current occuring on headphone driver’ s output. When the
output voltage (V
will turn off the charge pump’ s output. The charge pump’ s
output will turn on again if the situation has been removed.
Typical under voltage protection threshold is -2V with
0.5V hysteresis.
Low Drop-Out (LDO) Regulator
The LDO regulator’ s output provides maximum 200mA
drive capacity for external audio codec. A 2.2 F decoupling
capacitor with 0.1 f capacitor (filtering the high frequency
noise) is recommended at LDO regulator’ s output. The
LDO regulator has built-in under-voltage lockout circuits
to keep the output shuting off until internal circuitry is op-
erating properly. The under-voltage lockout function ini-
tiates a soft-start process after input voltage exceeds its
rising under-voltage lockout threshold during power on.
The internal soft-start circuit controls the rise rate of the
output voltage and limits the current surge during start-
up. Approximate 20 s delay time after the VDD is over the
under-voltage lockout threshold; the LDO regulator’ s out-
put voltage starts the soft-start. The typical soft-start inter-
val is about 130 s and the under-voltage lockout thresh-
old is 2.5V with 0.15V hysteresis.
Enable Mode
The APA2058 provides the independent enable control
functions and allows user disable any main circuit blocks
when not in using, and these can save the power
consumption. In addition, if either the power amplifier or
the headphone driver is disabled, the released time will
happen immediately when enable the power amplifier or
the headphone driver. However, if both the power ampli-
fier and the headphone driver are disabled at the same
time, the released time will be the T
enable one of them. Disable all blocks ( V
V
mode, and only consumption 5 A(Max.) at V
rent and 2 A(Max.) at HV
Copyright
Rev. A.5 - Feb., 2010
HP_EN
The charge pump monitors the output voltage (V
= V
LDO_EN
ANPEC Electronics Corp.
=0V), The APA2058 enters the shutdown
SS
) is greater than –2V, the charge pump
DD
supply current.
START-UP
DD
Time when
supply cur-
AMP_EN
SS
=5V,
). In
22
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