R

in

R

in

R

fb

R

fb

+

-

C

in

C

in

- In

+ In

R

in

R

fb

+

-

C

in

- In

R

in

R

fb

R

x

+

-

C

x

C

in

+ In

Differential

Input

Inverting

Non

Inverting

DRV604

SLOS659 – JANUARY 2010

www.ti.com

Decoupling Capacitors

The DRV604 is a DirectPath™ amplifier that requires adequate power supply decoupling to ensure that the noise

and total harmonic distortion (THD) are low. A good low equivalent-series-resistance (ESR) ceramic capacitor,

typically 1µF, placed as close as possible to the device PVDD leads works best. Placing this decoupling

capacitor close to the DRV604 is important for the performance of the amplifier. For filtering lower frequency

noise signals, a 10µF or greater capacitor placed near the audio power amplifier would also help, but it is not

required in most applications because of the high PSRR of this device.

Gain Setting Resistors Ranges

of the amplifier. Table 1 lists the recommended resistor values for different gain settings.

Table 1. Recommended Resistor Values

INPUT RESISTOR

FEEDBACK RESISTOR

DIFFERENTIAL

INVERTING INPUT

NON INVERTING

INPUT GAIN

GAIN

INPUT GAIN

10 k

Ω

10 k

Ω

1.0 V/V

–1.0 V/V

2.0 V/V

10 k

Ω

15 k

Ω

1.5 V/V

–1.5 V/V

2.5 V/V

10 k

Ω

20 k

Ω

2.0 V/V

–2.0 V/V

3.0 V/V

4.7 k

Ω

47 k

Ω

10.0 V/V

–10.0 V/V

11.0 V/V

Figure 14. Differential, Inverting and Non-inverting Gain Configuration

Internal and External Under Voltage Detection and RESET Output

The DRV604 contains an internal precision band gap reference voltage and 2 comparators, one is used to

monitor the supply voltages, PVDD_LD and PVDD_HP, and the other to monitor an external user selectable

voltage on pin 25. The internal PVDD monitor is set at 2.8 V with 200 mV hysteresis.

The external under voltage detection can be used to shutdown the DRV604 before an input device can make a

pop. The shutdown threshold at the Ex_UVP pin is 1.25 V. A resistor divider is used to obtain the shutdown

threshold and hysteresis desired for the application.

10

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