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−
BANDGAP
1.5/2.0/2.5V
COMP_E0
Variable Reference
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−
Switch
Mux
Bandgap Reference
Local
Buffer
COMP_E1
Local
Buffer
Vref
REFMODEREQ
REFBGREQ
REFGENREQ
Vbandgap
ADC
Local
Buffer
REF Introduction
15.1 REF Introduction
The reference module (REF) is responsible for generation of all critical reference voltages that can be
used by various analog peripherals in a given device. These include but are not limited to the ADC12_B
and COMP_B modules, dependent upon the particular device. The heart of the reference system is the
bandgap from which all other references are derived by unity or noninverting gain stages. The REF
module consists of the bandgap and a noninverting buffer stage that generates the three voltage
reference available in the system, namely 1.5 V, 2.0 V, and 2.5 V. In addition, when requested, a buffered
bandgap voltage is also available.
Features of the REF include:
•
Centralized factory-trimmed bandgap with excellent PSRR, temperature coefficient, and accuracy
•
1.5 V, 2.0 V, 2.5 V user selectable internal references
•
Buffered bandgap voltage available to rest of system
•
Power saving features
The block diagram of the REF module is shown in
.
Figure 15-1. REF Block Diagram
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REF Module
SLAU272C – May 2011 – Revised November 2013
Copyright © 2011–2013, Texas Instruments Incorporated