Electrical Characteristics V

The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T

25˚C. (Continued)

Note 13: The Exposed-DAP of the LDA10B package should be electrically connected to GND or an electrically isolated copper area. the LM4990LD demo board

has the Exposed-DAP connected to GND with a PCB area of 86.7mils x 585mils (2.02mm x 14.86mm) on the copper top layer and 550mils x 710mils (13.97mm

x 18.03mm) on the copper bottom layer.

Note 14: The thermal performance of the LLP and exposed-DAP TSSOP packages when used with the exposed-DAP connected to a thermal plane is sufficient for

driving 4

Ω loads. The MSOP and ITL packages do not have the thermal performance necessary for driving 4Ω loads with a 5V supply and is not recommended for

this application.

Note 15: All bumps have the same thermal resistance and contribute equally when used to lower thermal resistance. All bumps must be connected to achieve

specified thermal resistance.

External Components Description

See (Figure 1)

Components

Functional Description

1.

R

i

Inverting input resistance which sets the closed-loop gain in conjunction with R

high pass filter with C

π R

2.

C

i

Input coupling capacitor which blocks the DC voltage at the amplifiers input terminals. Also creates a

highpass filter with R

π R

for an explanation of how to determine the value of C

3.

R

f

Feedback resistance which sets the closed-loop gain in conjunction with R

4.

C

S

Supply bypass capacitor which provides power supply filtering. Refer to the Power Supply Bypassing

section for information concerning proper placement and selection of the supply bypass capacitor.

5.

C

B

Bypass pin capacitor which provides half-supply filtering. Refer to the section, Proper Selection of External

Components, for information concerning proper placement and selection of C

Typical Performance Characteristics

LD and MH Specific Characteristics

THD+N+N vs Frequency

V

Ω, and P

THD+N+N vs Output Power

V

Ω,andf=1kHz

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20051031

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