LM4562HA/NOPB National Semiconductor, LM4562HA/NOPB Datasheet - Page 23

• Manufacturer Part Number: LM4562HA/NOPB
• Description: IC OPAMP AUDIO STER AB TO99-8
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM4562HA/NOPB

• Amplifier Type: Audio
• Number Of Circuits: 2
• Slew Rate: 20 V/µs
• Gain Bandwidth Product: 55MHz
• Current - Input Bias: 10nA
• Voltage - Input Offset: 100µV
• Current - Supply: 10mA
• Current - Output / Channel: 26mA
• Voltage - Supply, Single/dual (±): ±2.5 V ~ 17 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: TO-99-8, Metal Can
• Amplifier Class: AB
• No. Of Channels: 2
• Supply Voltage Range: ± 2.5V To ± 17V
• Load Impedance: 2kohm
• Operating Temperature Range: -40°C To +85°C
• Amplifier Case Style: TO-99
• No. Of Pins: 8
• Rohs Compliant: Yes
• For Use With: LM4562HABD - BOARD EVALUATION LM4562HA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Output Type: -
• -3db Bandwidth: -
• Other names: *LM4562HA; LM4562HA

Application Information
DISTORTION MEASUREMENTS
The vanishingly low residual distortion produced by LM4562
is below the capabilities of all commercially available equip-
ment. This makes distortion measurements just slightly more
difficult than simply connecting a distortion meter to the
amplifier’s inputs and outputs. The solution, however, is quite
simple: an additional resistor. Adding this resistor extends the
resolution of the distortion measurement equipment.
The LM4562’s low residual distortion is an input referred in-
ternal error. As shown in Figure 1, adding the 10Ω resistor
connected between the amplifier’s inverting and non-inverting
inputs changes the amplifier’s noise gain. The result is that
FIGURE 1. THD+N and IMD Distortion Test Circuit
23
the error signal (distortion) is amplified by a factor of 101. Al-
though the amplifier’s closed-loop gain is unaltered, the feed-
back available to correct distortion errors is reduced by 101,
which means that measurement resolution increases by 101.
To ensure minimum effects on distortion measurements,
keep the value of R1 low as shown in Figure 1.
This technique is verified by duplicating the measurements
with high closed loop gain and/or making the measurements
at high frequencies. Doing so produces distortion compo-
nents that are within the measurement equipment’s capabili-
ties. This datasheet’s THD+N and IMD values were generat-
ed using the above described circuit connected to an Audio
Precision System Two Cascade.
201572k4
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