lm4985tmx National Semiconductor Corporation, lm4985tmx Datasheet - Page 9

• Manufacturer Part Number: lm4985tmx
• Description: Stereo 135mw Low Noise Headphone Amplifier With Selectable Capacitively Coupled Or Output Capacitor-less Ocl Output And Digitally Controlled I2c V
• Manufacturer: National Semiconductor Corporation

A
∆A
V
VMAX
OS
Electrical Characteristics V
The following specifications apply for R
25˚C.
Note 1: All voltages are measured with respect to the GND pin unless otherwise specified.
Note 2: 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 guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which
guarantee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit
is given, however, the typical value is a good indication of device performance.
Note 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX, θ
allowable power dissipation is P
currents for more information.
Note 4: Human Body Model: 100pF discharged through a 1.5kΩ resistor.
Note 5: Machine Model: 200pF ≤ C
Note 6: Typicals are measured at 25˚C and represent the parametric norm.
Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 8: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.
Note 9: 10Ω terminated input.
Note 10: The LDA10A package has its exposed-DAP soldered to an exposed 1.2in
Note 11: The wake-up time (T
External Components Description
Components
V
1.
2.
3.
6.
Symbol
C
C
C
C
S
B
o
I
Maximum Gain
Gain Accuracy per Step
Output Offset Voltage
Input coupling capacitor which blocks the DC voltage at the amplifier’s input terminals. Also creates a
high-pass filter with R
an explanation of how to determine the value of C
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.
Bypass pin capacitor which provides half-supply filtering. Refer to the section, Proper Selection of Proper
Components, for information concerning proper placement and selection of C
Output coupling capacitor which blocks the DC voltage at the amplifier’s output. Forms a high pass filter with
R
L
at f
WU
DMAX
o
= 1/(2πR
) is calculated using the following formula; T
mm
Parameter
= (T
≤ 220pF discharged through all pins.
JMAX
L
C
- T
o
A
)
L
)/ θ
i
= 16Ω, f = 1kHz, and C
at f
JA
or the number given in Absolute Maximum Ratings, whichever is lower. For the LM4985, see power derating
c
DD
= 1/(2πR
= 2.5V
Code = 11111
18dB ≥ A
–44dB ≥ A
OCL
R
V
IN
LOAD
i
C
= AC GND
i
). Refer to the section Proper Selection of External Components, for
(Figure 2)
= 32Ω
Functional Description
WU
(Notes 1, 2) (Continued)
V
9
V
≥ –44dB
= [C
B
>
2
Conditions
= 4.7µF unless otherwise specified. Limits apply to T
area of 1oz. Printed circuit board copper.
–76dB
BYPASS
i
.
(VDD) / 2 (I
BYPASS
JA
, and the ambient temperature, T
)] + 40ms.
(Note 6)
±
±
B
Typ
2.0
18
0.5
1.0
LM4985
(Notes 7,
Limit
8)
A
. The maximum
www.national.com
(Limits)
A
Units
=
mV
dB
dB