Datasheet

LM4991
SNAS217A –MAY 2004–REVISED APRIL 2013 www.ti.com
Electrical Characteristics V
DD
= 3V
(1) (2)
(continued)
The following specifications apply for V
DD
= 3V and R
L
= 8Ω unless otherwise specified. Limits apply for T
A
= 25°C.
LM4991
Parameter Test Conditions
Units
Typ
(3)
Limit
(4)
(Limits)
PSRR Power Supply Rejection Ratio V
RIPPLE
= 200mV sine p-p,
Input terminated with 10Ω, 68 dB
f = 1kHz
Electrical Characteristics V
DD
= 2.6V
(1) (2)
The following specifications apply for V
DD
= 2.6V and R
L
= 8Ω unless otherwise specified. Limits apply for T
A
= 25°C.
LM4991
Parameter Test Conditions
Units
Typ
(3)
Limits
(4)
(Limits)
Quiescent Power Supply Current V
IN
= 0V, no Load 2
I
DD
mA (max)
V
IN
= 0V, R
L
= 8Ω 3
I
SD
Shutdown Current V
SHUTDOWN
= V
DD
0.1 µA(max)
V
SDIH
Shutdown Voltage Input High 1 V
V
SDIL
Shutdown Voltage Input Low 0.9 V
V
OS
Output Offset Voltage 5 35 mV (max)
THD = 1% (max), f = 1kHz R
L
= 4Ω 400 mW
P
o
Output Power
R
L
= 8Ω 300 %
THD+N Total Harmonic Distortion+Noise P
O
= 0.15W, f = 1kHz 0.1
PSRR Power Supply Rejection Ratio V
RIPPLE
= 200mV sine p-p,
Input terminated with 10Ω, 51 dB
f = 1kHz
(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is functional, but do not ensure specific performance limits. Electrical Characteristics V
DD
= 5V state DC and AC
electrical specifications under particular test conditions which ensure specific performance limits. This assumes that the device is within
the Operating Ratings. Specifications are not ensure for parameters where no limit is given, however, the typical value is a good
indication of device performance.
(2) All voltages are measured with respect to the ground pin, unless otherwise specified.
(3) Typicals are specified at 25°C and represent the parametric norm.
(4) Limits are ensured to AOQL (Average Outgoing Quality Level).
External Components Description
(Figure 3)
Components Functional Description
1. R
i
Inverting input resistance that sets the closed-loop gain in conjunction with R
f
. This resistor also forms a high pass filter
with C
i
at f
C
= 1/(2π R
i
C
i
).
2. C
i
Input coupling capacitor that blocks the DC voltage at the amplifiers input terminals. Also creates a highpass filter with
R
i
at f
c
= 1/(2π R
i
C
i
). Refer to the section, PROPER SELECTION OF EXTERNAL COMPONENTS, for an explanation
of how to determine the value of C
i
.
3. R
f
Feedback resistance that sets the closed-loop gain in conjunction with R
i
.
4. C
S
Supply bypass capacitor that 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 that provides half-supply filtering. Refer to the section, PROPER SELECTION OF EXTERNAL
COMPONENTS, for information concerning proper placement and selection of C
B
.
4 Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated
Product Folder Links: LM4991