LME49610 Datasheet, PDF (11/21 Pages) National Semiconductor (TI) – High Performance, High Fidelity, High Current Audio Buffer

LME49610
www.ti.com
SNAS435B – APRIL 2008 – REVISED APRIL 2013
For example, the LME49610’s output voltage can slew at a typical 2000V/μs. When driving a 100Ω load, the di/dt
current demand is 20 A/μs. This current flowing through an inductance of 50nH (approximately 1.5” of 22 gage
wire) will produce a 1V transient. In these and similar situations, place the parallel combination of a solid 5μF to
10μF tantalum capacitor and a ceramic 0.1μF capacitor as close as possible to the device supply pins.
Ceramic capacitor have very lower ESR (typically less than 10mΩ) and low ESL when compared to the same
valued tantalum capacitor. The ceramic capacitors, therefore, have superior AC performance for bypassing high
frequency noise.
In less demanding applications that have lighter loads or lower slew rates, the supply bypassing is not as critical.
Capacitor values in the range of 0.01μF to 0.1μF are adequate.
SIMPLIFIED LME49610 CIRCUIT DIAGRAM
The LME49610’s simplified circuit diagram is shown in Figure 29. The diagram shows the LME49610’s
complementary emitter follower design, bias circuit and bandwidth adjustment node.
Thermal
Shutdown
D1 - D7
Q1
IN
200:
BW
D8 - D14
V_CC
Q5
Q3
Q2
OUT
Q4
Q6
V_EE
Figure 29. Simplified Circuit Diagram
Figure 30 shows the LME49610 connected as an open-loop buffer. The source impedance and optional input
resistor, R_S, can alter the frequency response. As previously stated, the power supplies should be bypassed with
capacitors connected close to the LME49610’s power supply pins. Capacitor values as low as 0.01μF to 0.1μF
will ensure stable operation in lightly loaded applications, but high output current and fast output slewing can
demand large current transients from the power supplies. Place a recommended parallel combination of a solid
tantalum capacitor in the 5μF to 10μF range and a ceramic 0.1μF capacitor as close as possible to the device
supply pins.
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