Datasheet LT3980 (Analog Devices)

LT3980 58V, 2A, 2.4MHz Step-Down Switching Regulator with 85µA Quiescent Current
FeaTures DescripTion
■
Wide Input Range: Operation from 3.6V to 58V
The LT®3980 is an adjustable frequency (100kHz to ■
Overvoltage Lockout Protects Circuits Through 80V
2.4MHz) monolithic buck switching regulator that accepts
Transients
input voltages up to 58V (80V transient). A high efficiency ■
2A Maximum Output Current
200mΩ switch is included on the die along with a boost ■
Low Ripple (<15mV
Schottky diode and the necessary oscillator, control, and
P-P) Burst Mode
®
Operation: I
logic circuitry. Current mode topology is used for fast
Q = 85µA at 12VIN to 3.3VOUT
■
Adjustable Switching Frequency: 100kHz to 2.4MHz
transient response and good loop stability. Catch diode ■
Low Shutdown Current: I
current sense (DA pin) protects the circuit during input
Q < 1µA
■
Catch Diode Current Sense Protects Circuit Through
voltage transients even when a high switching frequency
Short-Circuit and Input Overvoltage
is used. Low ripple Burst Mode operation maintains high ■
Synchronizable Between 250kHz to 2MHz
efficiency at low output currents while keeping output ■ Power Good Flag ripple below 15mV in a typical application. In addition, the ■ Saturating Switch Design: 200mΩ On-Resistance LT3980 can further enhance low output current efficiency ■ Thermal Protection by drawing bias current from the output when VOUT is ■ Soft-Start Capability above 3V. Shutdown reduces input supply current to less ■ Small 16-Pin Thermally Enhanced MSOP and than 1µA while a resistor and capacitor on the RUN/SS 3mm × 4mm DFN Packages pin provide a controlled output voltage ramp (soft-start). A power good flag signals when VOUT reaches 91% of
applicaTions
the programmed output voltage. The LT3980 is available ■ in 16-pin MSOP and 3mm × 4mm DFN packages with Automotive Battery Regulation ■ exposed pads for low thermal resistance. Distributed Supply Regulation ■ Industrial Supplies 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 ■ Wall Transformer Regulation owners.
Typical applicaTion 5V Step-Down Converter Efficiency, VOUT = 5V
V V 95 IN OUT 6.5V TO 58V 5V VIN = 12V TRANSIENT 2A 90 TO 80V VIN BD 85 VIN = 24V OFF ON RUN/SS BOOST 80 VIN = 48V 0.47µF 4.75k 10µH 75 VC LT3980 SW 10µF 70 RT 22pF 1nF EFFICIENCY (%) 65 PG DA 60 97.6k 536k SYNC FB GND 55 f = 400kHz 100k 47µF D = DIODES, INC. SBR3U100LP 50 0 0.5 1 1.5 2 ILOAD (A) 3980 TA01 3980 TA01b 3980fa For more information www.linear.com/LT3980 1 Document Outline Features Description Applications Typical Application 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