SC416 Datasheet, PDF (1/34 Pages) Semtech Corporation – Dual Synchronous Buck Controller with Tracking Start-up/Shutdown

SC416
POWER MANAGEMENT
Features
Dual Synchronous Buck Controller
with Tracking Start-up/Shutdown
Description
„ 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
„ Proportional or Coincident Tracked Start-up and Shut-
down of Both Outputs
„ Adjustable Soft-start Rates for Each Output
„ Regulated Shutdown for Each Output
„ Low Shutdown Power
„ Constant On-Time for Fast Dynamic Response
„ Adjustable Switching Frequency
„ Separated Frequencies for Minimal Switching Interac-
tion:
• VOUT1 = up to 600kHz
• VOUT2 = up to 720kHz
„ Power Save or Continuous Operation at Light Load
„ 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 Lead-free Package
„ Industrial Temperature Range
„ WEEE and RoHS Compliant
Applications
„ Notebook and Sub-Notebook Graphics
„ Voltage Controllers
„ Tablet PCs
„ Embedded Applications
The SC416 is a versatile, constant on-time, pseudo-
fixed-frequency, dual synchronous buck PWM control-
ler intended for notebook computers and other battery
operated portable devices. The SC416 contains all the
features needed to provide cost-effective control of two
independent switchmode power supplies.
The SC416 provides adjustable voltage tracking during
start-up and shut-down, making it an effective solution
for a variety of applications where the voltage differen-
tial between supply rails must meet defined limits dur-
ing all operating conditions including start-up and shut-
down. The SC416 supports proportional tracking which
gives equal start-up and shut-down times for both out-
puts, and can also provide coincident tracking where the
two output voltages are equal during the lower voltage’s
start-up and shut-down ramp.
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, regulated shutdown, selectable power save
and non-overlapping gate drive. The SC416 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
SC416 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 SC416 reduces switching frequency for im-
proved efficiency.
May 17, 2007
© 2007 Semtech Corporation
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