SC415_08 Datasheet, PDF (1/30 Pages) Semtech Corporation – Dual Synchronous Buck Controller

SC415
Dual Synchronous Buck Controller
POWER MANAGEMENT
Features
„ VIN Range 3-25V
„ Outputs Adjustable from 0.75 to 5.25V,
„ or Preset Output Voltages:
• VOUT1 = 1.8 or 1.5V
• VOUT2 = 1.25 or 1.05V
„ Low Shutdown Power
„ Constant On-Time for Fast Dynamic Response
„ Adjustable Switching Frequency
„ Separated Frequencies for Minimal Switching
Interaction:
• VOUT1 = up to 600kHz
• VOUT2 = up to 720kHz
„ Power Save or Continuous Operation at Light Load
„ Adjustable Soft-start Rates for Each Output
„ Soft-Shutdown for Each Output
„ Over-Voltage and Under-Voltage Fault Protection
„ Cycle-by-Cycle Valley Current Limit
„ DC Current Sense Using Low-Side RDSON Sensing,
or RSENSE in Source of Low-Side MOSFET for Greater
Accuracy
„ Separate Power Good Outputs
„ Separate Enable/Power Save Inputs
„ 3.1A Non-Overlapping Gate Drive
„ SmartDrive^TM for High-Side MOSFET
„ MLP 4x4 24 Pin Package
„ Industrial Temperature Range
Applications
„ Notebook and Sub-Notebook Graphics
„ Voltage Controllers
„ Tablet PCs
„ Embedded Applications
Description
The SC415 is a versatile, constant on-time, pseudo fixed-
frequency, dual synchronous buck PWM controller
intended for notebook computers and other battery
operated portable devices. The SC415 contains all the
features needed to provide cost-effective control of two
independent switchmode power supplies.
The two DC outputs are adjustable from 0.75V to 5.25V.
Additional features for each output include cycle-by-
cycle current limit, voltage soft-start, under-voltage and
over-voltage protection, programmable over-current
protection, soft shutdown, selectable power save and
non-overlapping gate drive. The SC415 provides two
enable/power save inputs, two soft-start inputs, two
power good outputs and an on-time adjust input.
The constant on-time topology provides fast dynamic
response. The excellent transient response means that
SC415 based solutions require less output capacitance
than competing fixed-frequency converters. Switching
frequency is constant until a step in load or line voltage
occurs, at which time the pulse density and frequency
moves to counter the change in output voltage. After the
transient event, the controller frequency returns to steady
state operation. At light loads with power save enabled,
the SC415 reduces switching frequency for improved
efficiency.
July 23, 2008
© 2008 Semtech Corporation
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