PAM8615 datasheet(11/13 Pages) PAM

11 / 13 page

Power Analog Microelectronics Inc

www.poweranalog.com

Using low-ESR Capacitors

Short-circuit Protection

Thermal Protection

Master-Slave and SYNC Operation

L o w - E S R

c a p a c i t o r s

a r e

r e c o m m e n d e d

throughout this application section. A real (with

respect to ideal) capacitor can be modeled simply

as a resistor in series with an ideal capacitor. The

voltage drop across this resistor minimizes the

beneficial effects of the capacitor in the circuit.

The lower the equivalent value of this resistance

the more the real capacitor behaves as an ideal

capacitor.

The PAM8615 has short circuit protection circuitry

on the outputs to prevent damage to the device

when output-to-output shorts (BTL mode), output-

to-GND shorts, or output-to-VCC shorts occur.

Once a short-circuit is detected on the outputs,

the output drive is immediately disabled. This is a

latched fault and must be reset by cycling the

voltage on the SD pin to a logic low and back to

the logic high state for normal operation. This will

clear the short-circuit flag and allow for normal

operation if the short was removed. If the short

was not removed, the protection circuitry will

again activate.

Thermal protection on the PAM8615 prevents

damage to the device when the internal die

temperature exceeds 160°C. There is a ±15

degree tolerance on this trip point from device to

device. Once the die temperature exceeds the set

thermal point, the device enters into the shutdown

state and the outputs are disabled. This is not a

latched fault. The thermal fault is cleared once the

temperature of the die is reduced by 40°C. The

device begins normal operation at this point

without external system intervention.

The MS/SL and SYNC terminals can be used to

synchronize the frequency of the class-D output

switching. When the MS/SL is high or left floating

due to the internal pull up resistor, the switching

frequency is determined by the ROSC. The SYNC

becomes an output whose source/sink current is

about 0.5mA, and the frequency of this output is

also determined by the ROSC. And this output can

be co nne cte d to a noth er PAM8 615 w ho is

co n f ig u re d in t h e sla ve m o d e . Th e o u tp u t

switching is synchronized to avoid any beat

frequencies that occur in the audio band when two

Class-D amplifiers in the same system are

switching at the slight different frequencies.

When the MS/SL is low, the switching frequency is

determined by the incoming square wave on the

SYNC input. The SNYC becomes an input in this

mode and accept a square wave from another

PAM8615 configured in the master mode or from

an external GPIO.

(Key: MS/SL=”H”, Master Mode, MS/SL=”L”,

Slave Mode)

PAM8615

16W/32W Stereo Class-D Audio Power Amplifier

02/2012 Rev1.1

OUT_L

L 1

CB1

OUT_R

L 2

CB2

MS/SL

SYNC

Rosc

INL

INR

PAM8615

(Master)

"H"=Master

L 3

OUT+

OUT-

L 4

IN-

IN+

PAM8615

(Slave)

SYNC

MS/SL

Rosc

GND=Slave

Rosc

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