Dual output controller Asynchronous start mode Power sequencing preven

The Datasheet Archive - 100 Million Datasheets from 7500 Manufacturers.

Dual output controller Asynchronous start mode Power sequencing preven

Datasheet Thumbnail

Top Searches for this datasheet

High Performance Wide Input Range Dual Synchronous Buck Controller
Dual output controller Asynchronous start mode Power sequencing prevent latch-ups phase operation input ripple Over current protection Output down 0.75V Wide input range, SC2442 SC2442H regulator with external transistor Programmable clock frequency 1MHz synchronous bucks high efficiency high current +125 operating temperature Small package TSSOP-24
SC2442/H
SC2442 SC2442H high performance dual buck converter controllers that configured variety synchronous buck applications where efficiency most important. Both converters synchronized prevent beat frequencies. dual buck converters also operated phase reducing input ripple, allowing fewer input capacitors. High frequency operation reduces size output inductors capacitors. controller separate power pins both improve noise immunity. supplies regulated using external transistor. Other features include: bootstrapping high side drive supplies, asynchronous mode start power sequencing prevent latch-ups, individual soft start each convertor, bootstrapped drivers high side N-channel MOSFETs, input side current sensing, dual mode current limit with hiccup, enable external frequency synchronization.
Applications
Point load converter applications applications with multiple output voltages Power management mixed signal applications Cable modems boxes.
SC2442 operates over range 4.5V SC2442H operates over range 4.5V 36V.
Typical Application Circuit
VIN+ 30V/36V
AVCC PVCC AVCC GD1H BST1 BST2
VOUT1
VOUT2
SC2442ITSTR
PVCC
GD1L GD2H GD2L BST1 BST2 PGND AGND
SYNC/EN
Revision: October 2003
www.semtech.com
SC2442/H
POWER MANAGEMENT Absolute Maximum Ratings
Exceeding specifications below result permanent damage device, device malfunction. Operation outside parameters specified Electrical Characteristics section implied.
Parameter BST1, BST2 PGND SC2442 SC2442H PGND SC2442 SC2442H PGND PVCC, AVCC PGND BST1 PH1, BST2 GD1H PH1, GD2H GD1L, GD2L PGND PGND AGND PH1, swing PGND (for Other Pins AGND Junction Temperature Storage Temperature Range Lead Temperature (Soldering) Sec.
Symbol VBST1, VBST2
Maximum
Units
VBDI VOC1, VOC2 PVCC, AVCC
-0.3 +0.5 -0.3 -0.3 PVCC ±0.3
VPH1, VPH2
-0.3 AVCC +125 +150
Electrical Characteristics
Unless specified: 125°C, 24V, 500KHz
Parameter Undervoltage Lockout Start Threshold UVLO Hysteresis Power Supply Operating Current AVCC/PVCC Regulated Drive Current
Symbol
Test Conditions
Unit
VUVLO VHYST
AVCC rising AVCC falling
0.15
4.75
IQSC AVCC, PVCC IBDI
load, SYNC/EN AVCC
2003 Semtech Corp.
www.semtech.com
SC2442/H
POWER MANAGEMENT Electrical Characteristics (Cont.)
Unless specified: 125°C, 24V, 500KHz
Parameter Soft Start Charging Current Discharge Current Error Amplifier Voltage Feedback Reference Input Bias Current Open Loop Gain Unity Gain Bandwidth Output Source/Sink Current Output Slew Rate
Symbol
Test Conditions
Unit
ISS1, ISS2 ISS1, ISS2
VFB1, VFB2 IEABIAS
0.735
0.750
0.765
V/µS
Output Delay Oscillator Frequency Range Clock Frequency Oscillator Peak Voltage Oscillator Valley Voltage Sync/Enable Input Enable Thresheld Voltage Disable Thresheld Voltage Disable Shut Down Delay Sync Input High Level Sync Input Level Current Limit OC1, Current Limit Sense Feedback Threshold Hiccup Sense Drive Turn Delay
ROSC Internal Internal
VSYEN VSYEN
SYNC/EN Voltage rising SYNC/EN Voltage falling SYNC/EN 0.8V
VSYEN VSYEN
VOC1, VOC2 VFB1, VFB2 TOCDLY
0.450
-105 0.525
-125 0.610
2003 Semtech Corp.
www.semtech.com
SC2442/H
POWER MANAGEMENT Electrical Characteristics (Cont.)
Unless specified: 125°C, 24V, 500KHz
Parameter Gate Drive Outputs High Side Gate Drive Side Gate Drive Gate Drive Rise Time Gate Drive Fall Time Maximum Duty Cycle Minimum Duty Cycle Dead Time Between Gate Drives
Symbol
Test Conditions
Units
IGDH+, IGDHIGDL+, IGDLTRISE TFALL Dmax Dmin TDEAD
Soure/Sink Soure/Sink COUT 1000 COUT 1000 PWM1 PWM2 PWM1 PWM2
+0.5 +0.5
NOTES: Guaranteed design, tested production This device sensitive ESD. standard handling precautions required.
Configuration
View
AVCC BST1 GD1H GD1L PGND AGND ROSC SYNC/EN BST2 GD2H GD2L PVCC
Ordering Information
Part Number SC2442ITSTR TSSOP-24 SC2442HITSTR -40°C +125°C Package Temp. Range (TA)
Note: Only available tape reel packaging. reel contains 2500 devices.
TSSOP)
2003 Semtech Corp.
www.semtech.com
SC2442/H
POWER MANAGEMENT Descriptions
Name AVCC BST1 GD1H GD1L PGND PVCC GD2L GD2H BST2 SYNC/EN ROSC AGND Function Supply voltage analog circuit. Regulated from using external transistor. Base drive AVCC/PVCC regulator. Input supply voltage. Maximum SC2442 SC2442H. High side current sense VOUT1. Threshold Error amplifier output compensation VOUT1. Feedback input VOUT1. Soft start VOUT1. capacitor AGND sets soft start period. Boost capacitor connection VOUT1 high side gate drive. Connect external capacitor diode shown Typical Application Circuit. Gate drive high side MOSFET VOUT1. degrees phase with GD2H. Switching node VOUT1 external inductor connection. Gate drive side MOSFET VOUT1. Power ground gate drive return currents. Supply voltage output drivers. Gate drive side MOSFET VOUT2. Switching node VOUT2 external inductor connection. Gate drive high side MOSFET VOUT2. degrees phase with GD1H. Boost capacitor connection VOUT2 high side gate drive. Connect external capacitor diode shown Typical Application Circuit. Soft start VOUT2. capacitor AGND sets soft start period. Feedback input VOUT2. Error amplifier output compensation VOUT2. High side current sense VOUT2. Threshold Oscillator synchronization Enable pin. Oscillator frequency programming pin. Connect resistor AGND clock frequency. Analog signal ground.
2003 Semtech Corp.
www.semtech.com
SC2442/H
POWER MANAGEMENT Block Diagram
2003 Semtech Corp.
www.semtech.com
SC2442/H
POWER MANAGEMENT Application Information
Undervoltage Lockout undervoltage lockout circuitry monitors AVCC pin. During undervoltage lockout output drives turned both pins discharged ground. Typically, AVCC increasing, normal operation will occur until AVCC reaches 4.6V. AVCC falling, undervoltage lockout will occur until AVCC falls below 4.5V. Voltage Regulator Using external transistor shown Typical Applications Circuit, SC2442/H provide regulated AVCC supply. same AVCC with adequate filtering connected PVCC provide power output drives. AVCC regulated typical which provides optimum drive most Voltage power MOSFETs. will provide least regulate external PNP. voltages below pass transistor will always operating saturation recommended connect directly AVCC PVCC long maximum input voltage below left unconnected. Alternately additional supply available addition VIN, used separataley powering both VCCs. Soft Start Hiccup Mode SC2442/H controllers utilise asynchronous start provide glitch free output rise times. During start pins held gate drive signals also pulled low. Once AVCC reaches 4.6V above, capacitors charged internal current source. error amplifier outputs clamped respective voltages. voltage goes above oscillator valley voltage 1.5V, high-side driver will begin switching. low-side driver will begin switching until voltage reached 3.3V. During normal operation, SC2442/H will enter hiccup mode voltage above 3.3V voltage below 0.525V (70% 0.750V). this occurs GDxH GDxL signals will will begin sink sink current will slowly discharge capacitor until voltage reaches which will trigger begin sourcing convertor will operate asynchronous mode during hiccup.
2003 Semtech Corp.
Sync Enable When SYNC/EN pulled below output drives turned both pins discharged ground. When SYNC/EN pulled high above 1.8V, normal operation occurs. When external clock signal applied that marginally higher frequency that ROSC resistor, internal oscillator will synchronize this signal. external signal should have compatible transition. Operating Frequency operating frequency resistor from ROSC AGND. ROSC sets clock frequency that twice operating frequency each convertor. clock frequency given 30,000 ROSC ROSC kOhm. Current Limiting SC2442/H provide cycle-by-cycle current limiting sensing current input line. inductive resistor should used precise current sensing limiting. When voltage drop across sense resistor input line exceeds pulse latched reset until next clock cycle. Overcurrent condition affects only high side driver. filter should placed across sense resistor shown Typical Application Circuit reduce noise turn-on spikes. filter capacitor should connected between respective pins proper filtering. Typically ceramic similar capacitor placed between current sense resistor switching circuit. this capacitor value large, significantly distort current feedback waveform aross sense resistors. This should taken into account while designing overcurrent protection circuit. Gate Drive Considerations SC2442/H provide high side gate drive with bootstrapping shown Typical Application Circuit. ceramic capacitor recommended between each BSTx corresponding Phase Node. Each gate drive source sink minimum 0.5A current with dead time between transistions prevent shoot throughs.
www.semtech.com
SC2442/H
POWER MANAGEMENT Application Information (Contd)
J1-1
0.06R, 1/4W
4.75-6V
0.075R, 1/4W
FDS6982S
P1166.473T 3.3V/0.6A VOUT1
100R
100R
J1-2
3.3R
J2-1
J1-3 PVCC
J2-2 GD1H
FDS6982S
P1166.223T 1.8V/1A VOUT2
AVCC
J2-4
J2-3
ROSC
SC2442ITSTR
PVCC
GD1L GD2H GD2L BST1 BST2 PGND AGND
3.3R
BST1 BST2
100R
0.22
100R
40.2K
SYNC/EN
220K
100K
Application Circuit 3.3V/1.8V Power Dual Synchronous Buck Convertor
Input
3.3V Output 1.8V Output
Input output rise times with full load
2003 Semtech Corp. www.semtech.com
SC2442/H
POWER MANAGEMENT Application Information (Contd)
Switching waveforms Phase Node with full load. trace: 1.8V/1A Bottom trace: 3.3V/0.6A
Output ripple noise full load trace: 3.3V Output Bottom trace: 1.8V Output
1.8V Transient response 100% step load
3.3V Transient response 100% step load
2003 Semtech Corp.
www.semtech.com
SC2442/H
POWER MANAGEMENT Outline Drawing TSSOP-24
Land Pattern TSSOP-24
Contact Information
Semtech Corporation Power Management Products Division Flynn Road, Camarillo, 93012 Phone: (805)498-2111 (805)498-3804
2003 Semtech Corp. www.semtech.com

Dual output controller Asynchronous start mode Power sequencing preven

Top Searches for this datasheet

Other recent searches