SC2443_08 Datasheet, PDF (1/22 Pages) Semtech Corporation – Dual-Phase Single or Two Output Synchronous Step-Down Controller

POWER MANAGEMENT
Features
u Wide input voltage range: 4.7V to 16V
u 0.5V feedback voltage for low-voltage outputs
u Programmable frequency up to 1 MHz per phase
u 2-Phase synchronous continuous conduction mode for
high efficiency step-down converters
u Out-of-phase operation for low input current ripples
u Output source and sink currents
u Fixed frequency peak current-mode control
u 75mV/-110mV maximum current sense voltage
u Inductor DCR current-sensing for low-cost applications
u Dual outputs or 2-phase single output operation
u Excellent current sharing between individual phases
u Individual soft-start, overload shutdown and enable
u External reference input for DDR applications
u External synchronization
u Industrial temperature range
u 4mm X 4mm X1mm 24-lead MLPQ package
SC2443
Dual-Phase Single or Two Output
Synchronous Step-Down Controller
Description
The SC2443 is a high-frequency dual synchronous step-down
switching power supply controller. It provides out-of-phase
high-current output gate drives to all N-channel MOSFET power
stages. The SC2443 operates in synchronous continuous-con-
duction mode. Both phases are capable of maintaining regula-
tion with sourcing or sinking load currents, making the SC2443
suitable for generating both VDDQ and the tracking VTT for
DDR applications.
The SC2443 employs fixed frequency peak current-mode con-
trol for the ease of frequency compensation and fast transient
response.
The dual-phase step-down controllers of the SC2443 can be
used to produce two individually controlled and regulated out-
puts or a single output with shared current in each phase. The
Step-down controllers operate from an input of at least 4.7V
and are capable of regulating outputs as low as 0.5V
Applications
u Telecommunication power supplies
u DDR memory power supplies
u Graphic power supplies
u Servers and base stations
Individual soft-start and overload shutdown timer is included
in each step-down controller. The SC2443 implements hiccup
overload protection. In single output current share configura-
tion, the master timer controls the soft-start and overload shut-
down functions of both controllers.
Typical Application Circuit
VOUT1 VP1
VIN
U1
IN1-
1 _IN1-
2 _COMP1
3 _SYNC
4 _AGND
SC2443
5 _REF
6 _REFIN
GDL1 ¹⁸
PVCC ¹⁷
PGND ¹⁶
GDL2 ¹⁵
GDH2 ¹⁴
BST2 ¹³
VIN
VP1
VOUT1
IN1-
VIN
VOUT2
IN2-
VIN
IN2-
Dual Independent Outputs
VOUT1 VP1
VIN
U1
IN1-
1 _IN1-
2 _COMP1
3 _SYNC
4 _AGND
SC2443
5 _REF
6 _REFIN
GDL1 ¹⁸
PVCC ¹⁷
PGND ¹⁶
GDL2 ¹⁵
GDH2 ¹⁴
BST2 ¹³
VIN
VP1
VOUT1
IN1-
VIN
VIN
Single Output With Current Sharing
Aug. 2008
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