Rainbow Electronics MAX8649 - Manual (Page 11)

MAX8649
1.8A Step-Down Regulator with Differential
Remote Sense in 2mm x 2mm WLP
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I 2 C INTERFACE
VOLTAGE
CONTROL, V REF ,
BIAS, ETC.
PWM LOGIC
CLOCK GEN OSC
V DAC
SNS-
SNS+
PGND
LX
IN2
AGND
VID2
VID1
EN
IN1
SDA
SCL
V DD
SYNC
Figure 1. Block Diagram
Detailed Description
The MAX8649 high-efficiency, 3.25MHz step-down
switching regulator delivers up to 1.8A of output cur-
rent. The device operates from a 2.5V to 5.5V input
voltage range, and the output voltage is I
2 C program-
mable from 0.75V to 1.38V in 10mV increments. Fully
differential remote sense ensures precise DC regula-
tion at the load. Total output error is less than 2% over
load, line, and temperature.
Dynamic Voltage Scaling
The output voltage is dynamically adjusted by use of
the VID0 and VID1 logic inputs, allowing selection
between four predefined operation modes/voltage
configurations.
For each of the different output modes, the following
parameters are programmable:
• Output voltage from 0.75V to 1.38V in 10mV steps
• Mode of operation: Forced PWM or power save
• Enable/disable of synchronization of switching
frequency to external clock source
The relation between the VID0/VID1 and operation
mode is given by Table 1.
The VID_ inputs have internal pulldown resistors. These
pulldown resistors can be disabled through the CONTROL
register after the MAX8649 is enabled, achieving low-
est possible quiescent current. When EN is low, the
CONTROL register is reset to default, enabling the pull-
down resistors (see Table 7).
VID0 VID1 MODE I 2 C REGISTER
DEFAULT
SWITHCING
MODE
DEFAULT
SYN C H R O N IZ A TIO N
DEFAULT
OUTPUT
VOLTAGE (V)
0 0 MODE0 Table 3 FORCED PWM OFF 1.27
0 1 MODE1 Table 4 POWER SAVE OFF 1.05
1 0 MODE2 Table 5 FORCED PWM OFF 1.22
1 1 MODE3 Table 6 FORCED PWM OFF 1.05
Table 1. VID0 and VID1 Configuration