September 2007
LME49810
200V Audio Power Amplifier Driver with Baker Clamp
LME49810 200V Audio Power Amplifier Driver with Baker Clamp
General Description
The LME49810 is a high fidelity audio power amplifier driver
designed for demanding consumer and pro-audio applications. Amplifier output power may be scaled by changing the
supply voltage and number of power transistors. The
LME49810’s minimum output current is 50mA. When using a
discrete output stage the LME49810 is capable of delivering
in excess of 300 watts into a single-ended 8Ω load.
Unique to the LME49810 is an internal Baker Clamp. This
clamp insures that the amplifier output does not saturate
when over driven. The resultant “soft clipping” of high level
audio signals suppresses undesirable audio artifacts generated when conventional solid state amplifiers are driven hard
into clipping.
The LME49810 includes thermal shutdown circuitry that activates when the die temperature exceeds 150°C. The
LME49810’s mute function, when activated, mutes the input
drive signal and forces the amplifier output to a quiescent
state.
Key Specifications
■ Wide operating voltage range ±20V to ±100V
■ Slew Rate 50V/μs (typ)
■ Output Drive Current 60mA (typ)
■ PSRR (f = DC) 110dB (typ)
■ THD+N (f = 1kHz) 0.0007 (typ)
Features
Very high voltage operation
■
Output clamp logic output
■
Thermal shutdown and mute
■
Customizable external compensation
■
Scalable output power
■
Applications
Guitar amplifiers
■
Powered studio monitors
■
Powered subwoofers
■
Pro audio
■
Audio video receivers
■
High voltage industrial applications
■
Boomer® is a registered trademark of National Semiconductor Corporation.
Tru-GND is a trademark of National Semiconductor Corporation.
© 2007 National Semiconductor Corporation 202167 www.national.com
Typical Application
LME49810
FIGURE 1. LME49810 Audio Amplifier Schematic
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20216772
Connection Diagram
LME49810
TB Package
Pin Descriptions
Pin Pin Name Description
1 ClpFlag Baker Clamp Clip Flag Output
2 Mute Mute Control
3 GND Device Ground
4 IN+ Non-Inverting Input
5 IN– Inverting Input
6 Comp External Compensation Connection
7 NC No Connect, Pin electrically isolated
8 Osense Output Sense
9 NC No Connect, Pin electrically isolated
10 –V
11 Bias
12 Bias
13 Sink Output Sink
14 Source Output Source
15 +V
EE
CC
Top View
20216702
Order Number LME49810TB
See NS Package Number TB15A
N = National Logo
U = Fabrication plant code
Z = Assembly plant code
XY = 2 Digit date code
TT = Die traceability
TB = Package code
Negative Power Supply
M
P
Negative External Bias Control
Positive External Bias Control
Positive Power Supply
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LME49810
20216708
FIGURE 2. LME49810 Simplified Schematic
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LME49810
Absolute Maximum Ratings (Notes 1, 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage |V+| + |V-|
200V
T Package (10 seconds) 260°C
Storage Temperature –40°C to +150°C
Thermal Resistance
θ
θ
JA
JC
73°C/W
4°C/W
Differential Input Voltage ±6V
Common Mode Input Range 0.4VEE to 0.4V
CC
Power Dissipation (Note 3) 4W
ESD Susceptibility (Note 4) 1kV
ESD Susceptibility (Note 5) 200V
Junction Temperature (T
JMAX
) (Note 9)
150°C
Operating Ratings
Temperature Range
T
≤ TA ≤ T
MIN
Supply Voltage
MAX
−40°C ≤ TA ≤ +8 5°C
±20V ≤ V
SUPPLY
≤ ±100V
Soldering Information
Electrical Characteristics VCC = +100V, VEE = –100V (Notes 1, 2)
The following specifications apply for I
29dB.
Symbol Parameter Conditions
I
CC
I
EE
Quiescent Power Supply Current
Quiescent Power Supply Current
THD+N Total Harmonic Distortion + Noise
A
V
V
OM
V
NOISE
I
OUT
I
MUTE
Open Loop Gain
Output Voltage Swing
Output Noise
Output Current Current from Source to Sink Pins 60 50 mA (min)
Current into Mute Pin To activate the amplifier 100
SR Slew Rate
V
OS
I
B
Input Offset Voltage VCM = 0V, IO= 0mA 1 3 mV (max)
Input Bias Current VCM = 0V, IO= 0mA 100 200 nA (max)
PSRR Power Supply Rejection Ratio f = DC, Input Referred 110 105 dB (min)
V
V
V
I
BIAS
CLIP
BC
BA
Baker Clamp Clipping Voltage
Baker Clamp Flag Output Voltage
Bias P&M Pin Open Voltage BiasP - BiasM 10
Bias Adjust Function Current 2.8
= 100μA, unless otherwise specified. Limits apply for TA = 25°C, CC = 10pF, and AV =
MUTE
LME49810
VCM = 0V, VO = 0V, IO = 0A
VCM = 0V, VO = 0V, IO = 0A
No Load, BW = 30kHz
V
OUT
= 30V
, f = 1kHz
RMS
f = DC
f = 1kHz, VIN = 1mV
RMS
THD+N = 0.05%, f = 1kHz
BW = 30kHz,
A-weighted
Typical
(Note 6)
11 18 mA (max)
13 mA (max)
0.0007 % (max)
120
88
67.5
50
34 150
Limits
(Notes 7, 8)
50
200
VIN = 1V
f = 10kHz square Wave
P-P
,
50
Clip Output
Source pin
Sink pin
I
= 4.7mA
FLAG
97.2
–96.4
0.4
95.5
–95.5
Units
(Limits)
dB
dB
V
RMS
μV
μV (max)
μA (min)
μA (max)
V/μs(min)
V (max)
V (min)
V
V
mA
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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.
LME49810
Note 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by T
allowable power dissipation is P
C and the typical θJC is 4°C/W. Refer to the Thermal Considerations section for more information.
DMAX
= (T
- TA) / θJC or the number given in Absolute Maximum Ratings, whichever is lower. For the LME49810, T
JMAX
, θJC, and the ambient temperature, TA. The maximum
JMAX
Note 4: Human body model, 100pF discharged through a 1.5kΩ resistor.
Note 5: Machine Model, 220pF - 240pF discharged through all pins.
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: The maximum operating junction temperature is 150°C.
Note 10: Data taken with Bandwidth = 30kHz, AV = 29dB, CC = 10pF, and TA = 25°C except where specified.
JMAX
= 150°
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LME49810
FIGURE 3. LME49810 Test Circuit Schematic (DC Coupled)
20216709
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