Document
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 www.DataSheet4U.com 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 SmartDriveTM for High-Side MOSFET MLP 4x4 24 Pin Package Industrial Temperature Range
Description
The SC415 is a versatile, constant on-time, pseudo fixedfrequency, 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-bycycle 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.
• •
• •
Applications
Notebook and Sub-Notebook Graphics Voltage Controllers Tablet PCs Embedded Applications
Oct 08, 2007
© 2007 Semtech Corporation
1
SC415
Typical Application Circuit
www.DataSheet4U.com
VIN PGD1 Q1 PGD2 Q3 VIN
CIN1
CIN2
24
23
22
21
20
19
PGD1
PGD2
DH1
ILIM1
ILIM2
DH2
VOUT1 L1
D2
100NF
RLIM1
RLIM2 PAD LX2 BST2 VDD2 25 18 17 16
VOUT2
100NF
D3 L2
1 +5V + COUT1 Q2 2 3 4 5
LX1 BST1 VDD1 DL1 EN1
+5V + Q4 COUT2
SC415
VOUT1 VOUT2 TON RTN
DL2 EN2 SS2
15 14
1UF
13
1UF 10NF
EN1 VOUT1
6
SS1
FB1
FB2
10NF
EN2 VOUT2
10
11
1NF
12
RTON VIN
7
8
9
2
SC415
Pin Configuration
PGD1 PGD2 ILIM1 ILIM2 DH1 DH2
Ordering Information
Device
SC415MLTRT(1) SC415EVB
Package
MLPQ-24 4X4 Evaluation Board
24 LX1 BST1
www.DataSheet4U.com
19 18 TOP VIEW LX2 BST2 VDD2
1
VDD1 DL1
Notes: (1) Available in tape and reel only. A reel contains 3,000 devices. (2) Available in lead-free package only. Device is WEEE and RoHS compliant.
SC415
DL2 GND (PAD) 6 7
VOUT1 RTN TON FB2 FB1
EN1 SS1
EN2 13 12
VOUT2
SS2
MLPQ24: 4x4 24 LEAD
Marking Information
SC415 yyww xxxxx xxxxx
nnnn = Part Number (example: SC415 yyww = Date Code (example: 0652) xxxxx = Semtech Lot No. (example: 09010 xxxxx 01-10)
3
SC415
Absolute Maximum Ratings
DHx, BSTx, GND (DC) ……………………………… -03 to +30V DHx, BSTx to GND (transient - 100nsec max) ………… -2.0 to +33V LXx, TON to GND (DC) ……………………………… -0.3 to +25V LXx, TON to GND (transient - 100nsec max) ………… -2.0 to +28V BST1 to LX1, BST2 to LX2 (DC) ……………………… -0.3 to +6.0V BST1 to LX1, BST2 to LX2 (transient - 100nsec max) … 0.3 to +7.5V DLx to GND (DC) ……………………………………-0.3 to +6.0V
www.DataSheet4U.com
Thermal Information
Junction to Ambient(1) ……………………………… 29°C/W
Storage Temperature Range ……………… -60 to +150°C Operating Junction Temperature Range … -40 to +125°C
Lead Temperature (Soldering) 10 sec ………………… 260°C
GND to RTN ……………………………………… -0.3 to +0.3V VDDx to RTN ……………………………………… -0.3 to +6.0V ENx, FBx, ILIMx, PGDx, SSx, VOUTx to RTN…… -0.3 to VDDx +0.3V
Peak IR Reflow Temperature(10-40sec)………………. ESD Protection Level(2) …………………………………
260°C 2kV
Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not recommended. NOTES(1) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards. (2) Tested according to JEDEC standard JESD22-A114-B.
Electrical Characteristics
Test Conditions: VIN = 15V, VOUT = 1.5V, TA = 25 oC, 0.1% resistor dividers; RTON = 1Meg; VDD1/2 = 5.0V; GND connects to PAD pin.
25°C Parameter Input Supplies
VIN Input Voltage VDD.