Datasheet LT8705 (Analog Devices)

LT8705 80V VIN and VOUT Synchronous 4-Switch Buck- Boost DC/DC Controller
FeaTures DescripTion
n
Single Inductor Allows VIN Above, Below, or Equal
The LT®8705 is a high performance buck-boost switch-
to Regulated VOUT
ing regulator controller that operates from input voltages n
V
above, below or equal to the output voltage. The part has
IN Range 2.8V (Need EXTVCC > 6.4V) to 80V
n
V
integrated input current, input voltage, output current
OUT Range: 1.3V to 80V
n
Quad N-Channel MOSFET Gate Drivers
and output voltage feedback loops. With a wide 2.8V to n
Synchronous Rectification: Up to 98% Efficiency
80V input and 1.3V to 80V output range, the LT8705 is n
Input and Output Current Monitor Pins
compatible with most solar, automotive, telecom and n
Synchronizable Fixed Frequency: 100kHz to 400kHz
battery-powered systems. n
Integrated Input Current, Input Voltage, Output Cur-
The LT8705 includes servo pins to indicate which feedback
rent and Output Voltage Feedback Loops
loops are active. The MODE pin selects among Burst Mode® n Clock Output Usable To Monitor Die Temperature operation, discontinuous or continuous conduction mode n Available in 38-Lead (5mm × 7mm) QFN and TSSOP at light loads. Additional features include a 3.3V/12mA Packages with the TSSOP Modified for Improved LDO, a synchronizable fixed operating frequency, onboard High Voltage Operation gate drivers, adjustable UVLO, along with input and output current monitoring with programmable maximum levels.
applicaTions
L, LT, LTC, LTM, Linear Technology, Burst Mode, µModule and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their n High Voltage Buck-Boost Converters respective owners. n Input or Output Current Limited Converters
Typical applicaTion Telecom Voltage Stabilizer
M1 VIN × 22µH 2 M4 VOUT 36V TO 48V 80V + + 220µF 4.7µF 5A M2 M3 4.7µF 220µF ×2 ×4 ×2 TO TO ×6 ×2 DIODE DIODE 0.22µF 1nF 10Ω 0.22µF 2Ω 10mΩ 1nF × 10Ω 2 2Ω 392k ×2
Efficiency and Power Loss
TG1 BOOST1 SW1 BG1 CSP CSN GND BG2 SW2 BOOST2 TG2 100 6 CSNIN CSPOUT CSPIN CSNOUT 5 95 VIN EXTVCC POWER LOSS (W) 4 SHDN FBOUT 100k SWEN INTVCC 10k 90 3 LDO33 GATEV LT8705 CC 4.7µF EFFICIENCY (%) MODE SRVO_FBIN 2 4.7µF 85 FBIN SRVO_FBOUT 1 RT SRVO_IIN 4Ω VOUT = 48V ILOAD = 2A 71.5k SS SRVO_IOUT 80 0 IMON_IN 30 40 50 60 70 80 1µF TO TO VIN (V) 8705 TA01b IMON_OUT VC CLKOUT SYNC BOOST1 BOOST2 20k 215k 56.2k 202kHz 4.7µF 1µF 220pF 3.3nF 8705 TA01 8705ff For more information www.linear.com/LT8705 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