Datasheet

LM4990
www.ti.com
SNAS184E DECEMBER 2002REVISED MAY 2013
Electrical Characteristics V
DD
= 2.6V
(1)(2)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
= 25°C.
LM4990
Units
Symbol Parameter Conditions
(Limits)
Typical
(3)
Limit
(4)(5)
V
IN
= 0V, I
o
= 0A, No Load 2.0 mA
I
DD
Quiescent Power Supply Current
V
IN
= 0V, I
o
= 0A, 8 Load 3.0 mA
I
SD
Shutdown Current V
SD
= V
SD Mode
(6)
0.1 µA
V
SDIH
Shutdown Voltage Input High V
SD MODE
= V
DD
1.0 V
V
SDIL
Shutdown Voltage Input Low V
SD MODE
= V
DD
0.9 V
V
SDIH
Shutdown Voltage Input High V
SD MODE
= GND 1.2 V
V
SDIL
Shutdown Voltage Input Low V
SD MODE
= GND 1.0 V
V
OS
Output Offset Voltage 5 50 mV (max)
R
OUT
9.7 k (max)
Resistor Output to GND
(7)
8.5
7.0 k (min)
P
o
( 8 ) THD+N = 1% (max); f = 1kHz 300
Output Power mW
( 4 ) THD+N = 1% (max); f = 1kHz 400
T
WU
Wake-up time 70 ms
THD+N Total Harmonic Distortion+Noise P
o
= 0.15Wrms; f = 1kHz 0.1 %
+N
V
ripple
= 200mV sine p-p 51 (f = 217Hz)
PSRR Power Supply Rejection Ratio dB
Input terminated with 10 51 (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 intended to be functional but specific performance is not ensured. Electrical Characteristics 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 ensured 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 measured at 25°C and represent the parametric norm.
(4) Limits are specified to AOQL (Average Outgoing Quality Level).
(5) Datasheet min/max specification limits are specified by design, test, or statistical analysis.
(6) For DSBGA only, shutdown current is measured in a Normal Room Environment. Exposure to direct sunlight will increase I
SD
by a
maximum of 2µA.
(7) R
ROUT
is measured from the output pin to ground. This value represents the parallel combination of the 10k output resistors and the
two 20k resistors.
External Components Description
See (Figure 5)
Components Functional Description
1. R
i
Inverting input resistance which 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 which 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 which sets the closed-loop gain in conjunction with R
i
.
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
B
.
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