Datasheet LT8705A (Analog Devices)

LT8705A 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®8705A 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 LT8705A n
Input and Output Current Monitor Pins
is compatible with most solar, automotive, telecom and n
Synchronizable Fixed Frequency: 100kHz to 400kHz
battery-powered systems. The LT8705A is an improved pin n compatible version of the LT8705 and is recommended for
Integrated Input Current, Input Voltage, Output Cur-
new designs. See LT8705A vs LT8705 in the Applications
rent and Output Voltage Feedback Loops
n Information section for more information. Improved Light Load Transition from DCM to FCM n Improved IMON_OUT, IMON_IN Offset When Cold The LT8705A includes a MODE pin to select among Burst n Clock Output Usable To Monitor Die Temperature Mode® operation, discontinuous or continuous conduc- tion mode at light loads. Additional features include a 3.3V/12mA LDO, a synchronizable fixed operating fre-
applicaTions
quency, and onboard gate drivers. n High Voltage Buck-Boost Converters L, LT, LTC, LTM, Linear Technology, Burst Mode, µModule and the Linear logo are registered n trademarks of Linear Technology Corporation. All other trademarks are the property of their Input or Output Current Limited Converters respective owners.
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
Efficiency and Power Loss
×2 TG1 BOOST1 SW1 BG1 CSP CSN GND BG2 SW2 BOOST2 TG2 100 6 CSNIN CSPOUT 5 CSPIN CSNOUT 95 POWER LOSS (W) VIN EXTVCC 4 SHDN FBOUT 100k SWEN INTV 90 CC 10k 3 LDO33 GATEV LT8705A CC 4.7µF EFFICIENCY (%) 2 MODE SRVO_FBIN 4.7µF 85 FBIN SRVO_FBOUT 1 RT SRVO_IIN 4Ω VOUT = 48V ILOAD = 2A 71.5k SS SRVO_IOUT 80 0 30 40 50 60 70 80 IMON_IN 1µF V TO TO IN (V) 8705A TA01b IMON_OUT VC CLKOUT SYNC BOOST1 BOOST2 20k 215k 56.2k 202kHz 4.7µF 1µF 220pF 3.3nF 8705A TA01 8705af For more information www.linear.com/LT8705A 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 Typical Application Related Parts