Rev 1.6

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PI3749-x0

MRGN: Margin Control

By default, output voltage margining is disabled, corresponding to B3 being cleared. In this case, the reference to the error amplifier is at its

nominal value of 1.700V. When margining is enabled, the reference can be modified in 85 mV steps according to Table 7.

The MRGN state is always controlled by four bit wide volatile register. At power up, the register always resets to 4’b0000. The MRGN

address can be freely read and written, as there are no one-time programmable fuses involved.

MRGN state

MRGN data

Resultant Margin Function

MRGN_ENA<3>

MRGN<2..0>

Margin active?

Reference Voltage (V)

1

100

Yes

1.360

1

101

Yes

1.445

1

110

Yes

1.530

1

111

Yes

1.615

0

xxx

No (data ignored), default

1.700

1

000

Yes

1.785

1

001

Yes

1.870

1

010

Yes

1.955

1

011

Yes

2.040

Table 7 — Margin control register programming