Datasheet LT1961 (Linear Technology)
| Manufacturer | Linear Technology |
| Description | 1.5A, 1.25MHz Step-Up Switching Regulator |
| Pages / Page | 16 / 1 — FEATURES. DESCRIPTIO. 1.5A Switch in a Small MSOP Package. Constant … |
| Revision | A |
| File Format / Size | PDF / 163 Kb |
| Document Language | English |
FEATURES. DESCRIPTIO. 1.5A Switch in a Small MSOP Package. Constant 1.25MHz Switching Frequency
Model Line for this Datasheet
Text Version of Document
LT1961 1.5A, 1.25MHz Step-Up Switching Regulator
U FEATURES DESCRIPTIO
■
1.5A Switch in a Small MSOP Package
The LT®1961 is a 1.25MHz monolithic boost switching ■
Constant 1.25MHz Switching Frequency
regulator. A high efficiency 1.5A, 0.2Ω switch is included ■
Wide Operating Voltage Range: 3V to 25V
on the die together with all the control circuitry required to ■
High Efficiency 0.2
Ω
Switch
complete a high frequency, current-mode switching regu- ■
1.2V Feedback Reference Voltage
lator. Current-mode control provides fast transient re- ■ ±
2% Overall Output Voltage Tolerance
sponse and excellent loop stability. ■ Uses Low Profile Surface Mount External New design techniques achieve high efficiency at high Components switching frequencies over a wide operating voltage range. ■ Low Shutdown Current: 6μA A low dropout internal regulator maintains consistent ■ Synchronizable from 1.5MHz to 2MHz performance over a wide range of inputs from 24V sys- ■ Current-Mode Loop Control tems to Li-Ion batteries. An operating supply current of ■ Constant Maximum Switch Current Rating at All Duty 1mA maintains high efficiency, especially at lower output Cycles* currents. Shutdown reduces quiescent current to 6μA. ■ Thermally Enhanced Exposed Pad 8-Lead Plastic Maximum switch current remains constant at all duty MSOP Package cycles. Synchronization allows an external logic level
U APPLICATIO S
signal to increase the internal oscillator from 1.5MHz to 2MHz. ■ DSL Modems The LT1961 is available in an exposed pad, 8-pin MSOP ■ Portable Computers package. Full cycle-by-cycle switch current limit protec- ■ Battery-Powered Systems tion and thermal shutdown are provided. High frequency ■ Distributed Power operation allows the reduction of input and output filtering components and permits the use of chip inductors. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. *Patent Pending
U TYPICAL APPLICATIO Efficiency vs Load Current 5V to 12V Boost Converter
90 6.8μH 85 UPS120 VOUT V 80 IN 1 2 VIN V 12V 5V SW 0.5A* LT1961 2.2μF 90.9k OPEN 75 CERAMIC OR 5 6 SHDN FB HIGH EFFICIENCY (%) = ON SYNC GND VC 70 8 3,4 7 10μF 10k 6800pF CERAMIC 65 100pF 1% VIN = 5V 6.8k VOUT = 12V 60 0 100 200 300 400 500 *MAXIMUM OUTPUT CURRENT IS SUBJECT TO THERMAL DERATING. 1961 TA01 LOAD CURRENT (mA) 1961 TA01a 1961fa 1
U FEATURES DESCRIPTIO
■
1.5A Switch in a Small MSOP Package
The LT®1961 is a 1.25MHz monolithic boost switching ■
Constant 1.25MHz Switching Frequency
regulator. A high efficiency 1.5A, 0.2Ω switch is included ■
Wide Operating Voltage Range: 3V to 25V
on the die together with all the control circuitry required to ■
High Efficiency 0.2
Ω
Switch
complete a high frequency, current-mode switching regu- ■
1.2V Feedback Reference Voltage
lator. Current-mode control provides fast transient re- ■ ±
2% Overall Output Voltage Tolerance
sponse and excellent loop stability. ■ Uses Low Profile Surface Mount External New design techniques achieve high efficiency at high Components switching frequencies over a wide operating voltage range. ■ Low Shutdown Current: 6μA A low dropout internal regulator maintains consistent ■ Synchronizable from 1.5MHz to 2MHz performance over a wide range of inputs from 24V sys- ■ Current-Mode Loop Control tems to Li-Ion batteries. An operating supply current of ■ Constant Maximum Switch Current Rating at All Duty 1mA maintains high efficiency, especially at lower output Cycles* currents. Shutdown reduces quiescent current to 6μA. ■ Thermally Enhanced Exposed Pad 8-Lead Plastic Maximum switch current remains constant at all duty MSOP Package cycles. Synchronization allows an external logic level
U APPLICATIO S
signal to increase the internal oscillator from 1.5MHz to 2MHz. ■ DSL Modems The LT1961 is available in an exposed pad, 8-pin MSOP ■ Portable Computers package. Full cycle-by-cycle switch current limit protec- ■ Battery-Powered Systems tion and thermal shutdown are provided. High frequency ■ Distributed Power operation allows the reduction of input and output filtering components and permits the use of chip inductors. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. *Patent Pending
U TYPICAL APPLICATIO Efficiency vs Load Current 5V to 12V Boost Converter
90 6.8μH 85 UPS120 VOUT V 80 IN 1 2 VIN V 12V 5V SW 0.5A* LT1961 2.2μF 90.9k OPEN 75 CERAMIC OR 5 6 SHDN FB HIGH EFFICIENCY (%) = ON SYNC GND VC 70 8 3,4 7 10μF 10k 6800pF CERAMIC 65 100pF 1% VIN = 5V 6.8k VOUT = 12V 60 0 100 200 300 400 500 *MAXIMUM OUTPUT CURRENT IS SUBJECT TO THERMAL DERATING. 1961 TA01 LOAD CURRENT (mA) 1961 TA01a 1961fa 1
