
Electrical Characteristics (Notes 1, 2) (Continued)
The following specifications apply for V
+ = +35V, V = 35V with R
L =8 unless otherwise specified. Limits apply for TA =
25C.
Symbol
Parameter
Conditions
LM3875
Units
(Limits)
Typical
(Note 6)
Limit
(Note 7)
SNR
Signal-to-Noise Ratio
P
O = 1W, A-Weighted,
Measured at 1 kHz, R
S =25
98 dB
dB
P
O = 40W, A-Weighted,
Measured at 1 kHz, R
S =25
114 dB
dB
P
pk = 100W, A-Weighted,
Measured at 1 kHz, R
S =25
122 dB
dB
IMD
Intermodulation Distortion Test
60 Hz, 7 kHz, 4:1 (SMPTE)
60 Hz, 7 kHz, 1:1 (SMPTE)
0.004
0.006
%
*DC Electrical Test; refer to Test Circuit #1.
**AC Electrical Test; refer to Test Circuit #2.
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is func-
tional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guar-
antee 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 2: All voltages are measured with respect to supply GND, unless otherwise specified.
Note 3: For operating at case temperatures above 25C, the device must be derated based on a 150C maximum junction temperature and a thermal resistance of
θJC = 1.0C/W (junction to case). Refer to the Thermal Resistance figure in the Application Information section under Thermal Considerations.
Note 4: Human body model, 100 pF discharged through a 1.5 k
resistor.
Note 5: The operating junction temperature maximum is 150C, however, the instantaneous Safe Operating Area temperature is 250C.
Note 6: Typicals are measured at 25C and represent the parametric norm.
Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 8: The LM3875T package TA11B is a non-isolated package, setting the tab of the device and the heat sink at V potential when the LM3875 is directly mounted
to the heat sink using only thermal compound. If a mica washer is used in addition to thermal compound,
θCS (case to sink) is increased, but the heat sink will be
isolated from V.
Note 9: The feedback compensation network limits the bandwidth of the closed-loop response and so the slew rate will be reduced due to the high frequency roll-off.
Without feedback compensation, the slew rate is typically 16V/s.
Note 10: The output dropout voltage is the supply voltage minus the clipping voltage. Refer to the Clipping Voltage vs. Supply Voltage graph in the Typical Perfor-
mance Characteristics section.
Test Circuit #1 (DC Electrical Test Circuit)
DS011449-3
LM3875
www.national.com
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