8.3.3 Wide Gain-Bandwidth Product

Figure 6-10 shows the open-loop magnitude and phase response of the OPA859-Q1. Calculate the gain

frequency by a factor of 100. The open-loop response shows the OPA859-Q1 to have approximately 63° of

phase-margin when configured as a unity-gain buffer.

show approximately 5° of phase-margin variation over the entire temperature range. Semiconductor process

variation is the naturally occurring variation in the attributes of a transistor (Early-voltage, β, channel-length, and

width) and other passive elements (resistors and capacitors) when fabricated into an integrated circuit. The

process variation can occur across devices on a single wafer or across devices over multiple wafer lots over

corner and the variation one standard deviation from the nominal. The simulated results show less than 2° of

phase-margin difference within a standard deviation of process variation when the amplifier is configured as a

unity-gain bufffer.

Frequency (Hz)

-15

0

15

30

45

60

75

100k

1M

10M

100M

1G

D404

Figure 8-5. Open-Loop Gain vs Temperature

Frequency (Hz)

-15

0

15

30

45

60

75

100k

1M

10M

100M

1G

D405

V

)

V

)

Figure 8-6. Open-Loop Gain vs Process Variation

OPA859-Q1

SBOSA59 – FEBRUARY 2021

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