LTC3882_15 Datasheet, PDF (64/104 Pages) Linear Technology – Dual Output PolyPhase Step-Down DC/DC Voltage Mode Controller with Digital Power System Management

LTC3882
APPLICATIONS INFORMATION
SYSTEM
V_CC
TP0101K
102k
LT6703-2
V_S
10k
V_CC
–IN _–
10k
+
OUT
10k
TP0101K
V_DD33 V_DD25
2N2002
2.2µF
LTC3882
1µF
10k
SDA
10k
SCL
400mV
REFERENCE
WP GND
GND
LTC
CONTROLLER
HEADER
ISOLATED 5V
SDA
SCL
V_CC
4.7µF
V_DD33 V_DD25
2.2µF
1µF
LTC3882
SDA
SCL
WP GND
TO LTC DC1613
USB TO I²C/SMBus/PMBus
CONTROLLER
3882 F47
Figure 47. DC1613 Connection (V_CC Supply)
ENBA
STAT
GND
ENBB
SYSTEM
3.3V
LTC4413
INB
OUTB
V_CC
V_DD33
V_DD25
0.1µF
LTC3882
1µF
10k
CONTROL CIRCUIT
SDA
10k
INA
OUTA
SCL
WP GND
LTC
CONTROLLER
HEADER
ISOLATED 3.3V
SDA
SCL
0.1µF
V_CC
V_DD33 V_DD25
1µF
LTC3882
SDA
SCL
WP GND
TO LTC DC1613
USB TO I²C/SMBus/PMBus
CONTROLLER
3882 F48
Figure 48. DC1613 Connections (V_DD33 Supply)
Design Example
As a design example, consider a 132W 2-phase applica-
tion such as the one shown in Figure 53, where V_IN = 36V,
V_OUT = 3.3V, and I_OUT = 40A. A fully discrete power stage
design is employed to allow better optimization given these
demanding requirements. Assume that a secondary 5V
supply will be available in the system for the LTC3882 V_CC
supply. The necessary local bypassing is then provided for
the V_DD33 (2.2µF) and V_DD25 (1µF) LDO outputs. These
LDO outputs should not be shared with other ICs that
might have outputs of the same name, because they have
independent, internal control loops. When V_DD33 is used
3882f
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