LM6154BCMX/NOPB National Semiconductor, LM6154BCMX/NOPB Datasheet - Page 10

• Manufacturer Part Number: LM6154BCMX/NOPB
• Description: IC OP AMP QUAD RRIO 14-SOIC
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM6154BCMX/NOPB

• Amplifier Type: General Purpose
• Number Of Circuits: 4
• Output Type: Rail-to-Rail
• Slew Rate: 30 V/µs
• Gain Bandwidth Product: 80MHz
• Current - Input Bias: 500nA
• Voltage - Input Offset: 300µV
• Current - Supply: 1.6mA
• Current - Output / Channel: 16.9mA
• Voltage - Supply, Single/dual (±): 2.7 V ~ 24 V, ±1.35 V ~ 12 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• -3db Bandwidth: -
• Other names: *LM6154BCMX; *LM6154BCMX/NOPB; LM6154BCMX

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Application Information
Unlike most bipolar op amps, the unique phase reversal
prevention/speed-up circuit in the input stage, caused the
slew rate to be very much a function of the input pulse
amplitude. This results in a 10 to 1 increase in slew rate
when the differential input signal increases. Large fast
pulses will raise the slew-rate to more than 30 V/µs.
FIGURE 2. Slew Rate vs. V
(Continued)
DIFF
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10
The speed-up action adds stability to the system when driv-
ing large capacitive loads.
A conventional op amp exhibits a fixed maximum slew-rate
even though the differential input voltage rises due to the
lagging output voltage. In the LM6152/LM6154, increasing
lag causes the differential input voltage to increase but as it
does, the increased slew-rate keeps the output following the
input much better. This effectively reduces phase lag. As a
result, the LM6152/LM6154 can drive capacitive loads as
large as 470 pF at gain of 2 and above, and not oscillate.
Capacitive loads decrease the phase margin of all op amps.
This can lead to overshoot, ringing and oscillation. This is
caused by the output resistance of the amplifier and the load
capacitance forming an R-C phase shift network. The
LM6152/6154 senses this phase shift and partly compen-
sates for this effect.