DRV600_15 Datasheet, PDF (8/17 Pages) Texas Instruments – DIRECTPATH™ STEREO LINE DRIVER

DRV600
SLOS536 – JUNE 2007
www.ti.com
APPLICATION INFORMATION (continued)
Charge Pump Flying Capacitor and PVSS Capacitor
The charge pump flying capacitor serves to transfer charge during the generation of the negative supply voltage.
The PVSS capacitor must be at least equal to the charge pump capacitor in order to allow maximum charge
transfer. Low ESR capacitors are an ideal selection, and a value of 2.2 µF is typical. Capacitor values that are
smaller than 2.2 µF can be used, but the maximum output power is reduced and the device may not operate to
specifications.
TOTAL HARMONIC DISTORTION + NOISE
vs
OUTPUT VOLTAGE
100
V_DD = 3.3 V,
R_L = 600 kW,
10 ^fIN ^{= 1kHz,}
1 mF Charge Pump Capacitor
1
0.1
0.01
0.001
3m
10m
100m 500m 1 2 3
V_O - Output Voltage - Vrms
Figure 14.
Decoupling Capacitors
The DRV600 is a DirectPath™ Line Driver amplifier that require 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 2.2 µF, placed as close as possible to the device V_DD lead works best. Placing this
decoupling capacitor close to the DRV600 is important for the performance of the amplifier. For filtering lower
frequency noise signals, a 10-µF 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.
Supply Voltage Limiting At 4.5 V
The DRV600 have a built-in charge pump which serves to generate a negative rail for the line driver. Because
the line driver operates from a positive voltage and negative voltage supply, circuitry has been implemented to
protect the devices in the amplifier from an overvoltage condition. Once the supply is above 4.5 V, the DRV600
can shut down in an overvoltage protection mode to prevent damage to the device. The DRV600 resume normal
operation once the supply is reduced to 4.5 V or lower.
Layout Recommendations
Exposed Pad On DRV600RTJ Package
The exposed metal pad on the DRV600RTJ package must be soldered down to a pad on the PCB in order to
maintain reliability. The pad on the PCB should be allowed to float and not be connected to ground or power.
Connecting this pad to power or ground prevents the device from working properly because it is connected
internally to PVSS.
SGND and PGND Connections
The SGND and PGND pins of the DRV600 must be routed separately back to the decoupling capacitor in order
to provide proper device operation. If the SGND and PGND pins are connected directly to each other, the part
functions without risk of failure, but the noise and THD performance do not meet the specifications.
8