Datasheet LTC3543 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 600mA Synchronous Step Down Buck Regulator with PLL, Soft-Start and Spread Spectrum |
| Pages / Page | 20 / 1 — FEATURES. DESCRIPTION. 600mA Output Current. 2.5V to 5.5V Input Voltage … |
| File Format / Size | PDF / 342 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. 600mA Output Current. 2.5V to 5.5V Input Voltage Range. 2.25MHz Constant-Frequency Operation, Spread
Model Line for this Datasheet
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LTC3543 600mA Synchronous Step Down Buck Regulator with PLL, Soft-Start and Spread Spectrum
FEATURES DESCRIPTION
n
600mA Output Current
The LTC®3543 is a high effi ciency monolithic synchronous n
2.5V to 5.5V Input Voltage Range
current mode buck regulator. n
2.25MHz Constant-Frequency Operation, Spread
The switching frequency is internally set at 2.25MHz,
Spectrum or Synchronized PLL (1MHz to 3MHz)
allowing the use of small surface mount inductors and n
High Effi ciency: Up to 95%
capacitors. In PLL mode, the LTC3543 can acquire fre- n
1A Peak Inductor Current
quencies between 1MHz and 3MHz. Also, the LTC3543 n
Very Low Quiescent Current: Only 45μA During
has spread spectrum capability providing a lower noise
Burst Mode Operation
regulated output, as well as low noise at the input. n No Schottky Diode Required n Low Dropout Operation: 100% Duty Cycle In Burst Mode® operation, the supply current is only 45μA, n Overtemperature Protected dropping to <1μA in shutdown. The 2.5V to 5.5V input n Stable with Ceramic Capacitors voltage range makes the LTC3543 ideally suited for single n Shutdown Mode Draws <1μA Supply Current Li-Ion battery-powered applications. The 100% duty cycle n ±2% Output Voltage Accuracy provides a low dropout operation, extending the battery n Current Mode Operation for Excellent Line and Load life in portable systems. Burst Mode operation increases Transient Response effi ciency at light loads, further extending battery life. n Soft-Start The internal synchronous switch increases effi ciency and n Available in a Low Profi le (0.75mm) 2mm × 3mm eliminates the need for an external Schottky diode. 6-Lead DFN Package L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective
APPLICATIONS
owners. Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131. n Portable Instruments n Cellular Phones
TYPICAL APPLICATION Effi ciency and Power Loss vs Load Current
3.3μH 100 1000 1.5V V 2.5V TO 5.5V V SW OUT IN 1.5V 90 VIN = 2.7V 10μF 10pF 10μF LTC3543 300k 80 V 100 IN = 4.2V POWER LOSS (mW) 70 PWR_EN RUN VFB 60 MODE MODE CAP V 50 IN = 3.6V 10 GND 200k 4nF 40 EFFICIENCY (%) POWER LOSS EXPOSED 30 AT VIN = 3.6V 10 PAD 3543 TA01a 20 MODE = V 10 IN m PULSE SKIP Burst Mode OPERATION ENABLED MODE = VFB m PULSE SKIP WITH SPREAD SPECTRUM 0 0.1 MODE = GND m Burst Mode OPERATION 0.1 1 10 100 1000 MODE = EXTERNAL CLOCK m PLL LOAD CURRENT (mA) 3543 TA01b 3543fa 1
FEATURES DESCRIPTION
n
600mA Output Current
The LTC®3543 is a high effi ciency monolithic synchronous n
2.5V to 5.5V Input Voltage Range
current mode buck regulator. n
2.25MHz Constant-Frequency Operation, Spread
The switching frequency is internally set at 2.25MHz,
Spectrum or Synchronized PLL (1MHz to 3MHz)
allowing the use of small surface mount inductors and n
High Effi ciency: Up to 95%
capacitors. In PLL mode, the LTC3543 can acquire fre- n
1A Peak Inductor Current
quencies between 1MHz and 3MHz. Also, the LTC3543 n
Very Low Quiescent Current: Only 45μA During
has spread spectrum capability providing a lower noise
Burst Mode Operation
regulated output, as well as low noise at the input. n No Schottky Diode Required n Low Dropout Operation: 100% Duty Cycle In Burst Mode® operation, the supply current is only 45μA, n Overtemperature Protected dropping to <1μA in shutdown. The 2.5V to 5.5V input n Stable with Ceramic Capacitors voltage range makes the LTC3543 ideally suited for single n Shutdown Mode Draws <1μA Supply Current Li-Ion battery-powered applications. The 100% duty cycle n ±2% Output Voltage Accuracy provides a low dropout operation, extending the battery n Current Mode Operation for Excellent Line and Load life in portable systems. Burst Mode operation increases Transient Response effi ciency at light loads, further extending battery life. n Soft-Start The internal synchronous switch increases effi ciency and n Available in a Low Profi le (0.75mm) 2mm × 3mm eliminates the need for an external Schottky diode. 6-Lead DFN Package L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective
APPLICATIONS
owners. Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131. n Portable Instruments n Cellular Phones
TYPICAL APPLICATION Effi ciency and Power Loss vs Load Current
3.3μH 100 1000 1.5V V 2.5V TO 5.5V V SW OUT IN 1.5V 90 VIN = 2.7V 10μF 10pF 10μF LTC3543 300k 80 V 100 IN = 4.2V POWER LOSS (mW) 70 PWR_EN RUN VFB 60 MODE MODE CAP V 50 IN = 3.6V 10 GND 200k 4nF 40 EFFICIENCY (%) POWER LOSS EXPOSED 30 AT VIN = 3.6V 10 PAD 3543 TA01a 20 MODE = V 10 IN m PULSE SKIP Burst Mode OPERATION ENABLED MODE = VFB m PULSE SKIP WITH SPREAD SPECTRUM 0 0.1 MODE = GND m Burst Mode OPERATION 0.1 1 10 100 1000 MODE = EXTERNAL CLOCK m PLL LOAD CURRENT (mA) 3543 TA01b 3543fa 1
