Datasheet LT8609, LT8609A, LT8609B (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 42V, 3A Synchronous Step-Down Regulator with 2.5µA Quiescent Current |
| Pages / Page | 26 / 1 — Wide Input Voltage Range: 3.0V to 42V. Ultralow Quiescent Current Burst … |
| Revision | H |
| File Format / Size | PDF / 327 Kb |
| Document Language | English |
Wide Input Voltage Range: 3.0V to 42V. Ultralow Quiescent Current Burst Mode® Operation:
Text Version of Document
LT8609/LT8609A/LT8609B 42V, 3A Synchronous Step-Down Regulator with 2.5µA Quiescent Current FEATURES DESCRIPTION n
Wide Input Voltage Range: 3.0V to 42V
The LT®8609/LT8609A/LT8609B is a compact, high effi- n
Ultralow Quiescent Current Burst Mode® Operation:
ciency, high speed synchronous monolithic step-down n
<2.5µA IQ Regulating 12VIN to 3.3VOUT
switching regulator that consumes only 1.7µA of non- n
Output Ripple <10mVP-P
switching quiescent current. The LT8609/LT8609A/ n
High Efficiency 2MHz Synchronous Operation:
LT8609B can deliver 3A of continuous current. Burst Mode n
>93% Efficiency at 1A, 5VOUT from 12VIN
operation enables high efficiency down to very low output n
3A Maximum Continuous Output
currents while keeping the output ripple below 10mVP-P. n
Fast Minimum Switch-On Time: 45ns
A SYNC pin allows synchronization to an external clock, or n
Adjustable and Synchronizable: 200kHz to 2.2MHz
spread spectrum modulation for low EMI operation. Internal n
Spread Spectrum Frequency Modulation for Low EMI
compensation with peak current mode topology allows the n Allows Use of Small Inductors use of small inductors and results in fast transient response n Low Dropout and good loop stability. The EN/UV pin has an accurate 1V n Peak Current Mode Operation threshold and can be used to program VIN UVLO or to shut n Accurate 1V Enable Pin Threshold down the part. A capacitor on the TR/SS pin programs the n Internal Compensation output voltage ramp rate during start-up while the PG flag n Output Soft-Start and Tracking signals when VOUT is within ±8.5% of the programmed n Small 10-Lead or 16-Lead MSOP Package output voltage as well as fault conditions. The LT8609A has slower switch edges for lower EMI emissions. The LT8609B operates in pulse-skipping mode only. APPLICATIONS n GSM Transceivers
PULSE-SKIPPING MODE, Burst Mode OPERATION SWITCH EDGE SPEED
n General Purpose Step-Down LT8609 Both Fast n Low EMI Step-Down LT8609A Both Medium All registered trademarks and trademarks are the property of their respective owners. LT8609B Pulse-Skipping Fast TYPICAL APPLICATION
12VIN to 5VOUT Efficiency
100
5V, 2MHz Step-Down
L = 2.2µH 95 fSW = 2MHz 90 VIN VIN BST 6V TO 40V 85 4.7µF ON OFF EN/UV 0.1µF 2.2µH VOUT SYNC SW 5V 80 10pF 3A LT8609 75 INTVCC 70 TR/SS PG 1M EFFICIENCY (%) RT FB 65 1µF 18.2k 187k 22µF 60 GND 55 8609 TA01a 500.00 0.50 1.00 1.50 2.00 2.50 3 IOUT (A) 8609 TA01b Rev. H Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
Wide Input Voltage Range: 3.0V to 42V
The LT®8609/LT8609A/LT8609B is a compact, high effi- n
Ultralow Quiescent Current Burst Mode® Operation:
ciency, high speed synchronous monolithic step-down n
<2.5µA IQ Regulating 12VIN to 3.3VOUT
switching regulator that consumes only 1.7µA of non- n
Output Ripple <10mVP-P
switching quiescent current. The LT8609/LT8609A/ n
High Efficiency 2MHz Synchronous Operation:
LT8609B can deliver 3A of continuous current. Burst Mode n
>93% Efficiency at 1A, 5VOUT from 12VIN
operation enables high efficiency down to very low output n
3A Maximum Continuous Output
currents while keeping the output ripple below 10mVP-P. n
Fast Minimum Switch-On Time: 45ns
A SYNC pin allows synchronization to an external clock, or n
Adjustable and Synchronizable: 200kHz to 2.2MHz
spread spectrum modulation for low EMI operation. Internal n
Spread Spectrum Frequency Modulation for Low EMI
compensation with peak current mode topology allows the n Allows Use of Small Inductors use of small inductors and results in fast transient response n Low Dropout and good loop stability. The EN/UV pin has an accurate 1V n Peak Current Mode Operation threshold and can be used to program VIN UVLO or to shut n Accurate 1V Enable Pin Threshold down the part. A capacitor on the TR/SS pin programs the n Internal Compensation output voltage ramp rate during start-up while the PG flag n Output Soft-Start and Tracking signals when VOUT is within ±8.5% of the programmed n Small 10-Lead or 16-Lead MSOP Package output voltage as well as fault conditions. The LT8609A has slower switch edges for lower EMI emissions. The LT8609B operates in pulse-skipping mode only. APPLICATIONS n GSM Transceivers
PULSE-SKIPPING MODE, Burst Mode OPERATION SWITCH EDGE SPEED
n General Purpose Step-Down LT8609 Both Fast n Low EMI Step-Down LT8609A Both Medium All registered trademarks and trademarks are the property of their respective owners. LT8609B Pulse-Skipping Fast TYPICAL APPLICATION
12VIN to 5VOUT Efficiency
100
5V, 2MHz Step-Down
L = 2.2µH 95 fSW = 2MHz 90 VIN VIN BST 6V TO 40V 85 4.7µF ON OFF EN/UV 0.1µF 2.2µH VOUT SYNC SW 5V 80 10pF 3A LT8609 75 INTVCC 70 TR/SS PG 1M EFFICIENCY (%) RT FB 65 1µF 18.2k 187k 22µF 60 GND 55 8609 TA01a 500.00 0.50 1.00 1.50 2.00 2.50 3 IOUT (A) 8609 TA01b Rev. H Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
