LT8620_15 Datasheet, PDF (1/26 Pages) Linear Technology – 65V, 2A Synchronous Step-Down Regulator with 2.5A Quiescent Current

FEATURES
nn _{Wide Input Voltage Range: 3.4V to 65V}
nn _{Ultralow Quiescent Current Burst Mode}^® _Operation:
nn _{2.5μA IQ Regulating 12VIN to 3.3VOUT}
nn _{Output Ripple < 10mVP-P}
nn _{High Efficiency Synchronous Operation:}
nn _{94% Efficiency at 1A, 12VIN to 5VOUT}
nn _{92% Efficiency at 1A, 12VIN to 3.3VOUT}
nn _{Fast 30ns Minimum Switch-On Time}
nn _{Low Dropout Under All Conditions: 250mV at 1A}
nn _{Safely Tolerates Inductor Saturation in Overload}
nn _{Low EMI}
nn _{Adjustable and Synchronizable: 200kHz to 2.2MHz}
nn _{Accurate 1V Enable Pin Threshold}
nn _{Internal Compensation}
nn _{Output Soft-Start and Tracking}
nn _{Small Thermally Enhanced 16-Lead MSOP and}
24-Lead 3mm × 5mm QFN Packages
APPLICATIONS
nn _{Automotive and Industrial Supplies}
nn _{General Purpose Step-Down}
nn _{GSM Power Supplies}
LT8620
65V, 2A Synchronous
Step-Down Regulator
with 2.5µA Quiescent
Current
DESCRIPTION
The LT^®8620 is a compact, high efficiency, high speed
synchronous monolithic step-down switching regulator
that accepts a wide input voltage range up to 65V, and
consumes only 2.5µA of quiescent current. Top and bottom
power switches are included with all necessary circuitry
to minimize the need for external components. Low ripple
Burst Mode operation enables high efficiency down to
very low output currents while keeping the output ripple
below 10mV_P-P. A SYNC pin allows synchronization to an
external clock. Internal compensation with peak current
mode topology allows the use of small inductors and
results in fast transient response and good loop stability.
The EN/UV pin has an accurate 1V threshold and can be
used to program V_IN undervoltage lockout or to shut down
the LT8620 reducing the input supply current to 1µA. A
capacitor on the TR/SS pin programs the output voltage
ramp rate during start-up. The PG flag signals when V_OUT
is within ±9% of the programmed output voltage as well as
fault conditions. The LT8620 is available in small 16-Lead
MSOP and 3mm × 5mm QFN packages with exposed pads
for low thermal resistance.
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
TYPICAL APPLICATION
5V 2A Step-Down Converter
V_IN
5.5V TO 65V
4.7µF
10nF
1µF
V_IN
BST
EN/UV
PG
SW
LT8620
SYNC
BIAS
TR/SS
FB
INTV_CC
RT
GND
60.4k
0.1µF
4.7µH
1M
10pF
243k
f_SW = 700kHz
8620 TA01a
V_OUT
5V
47µF ^2A
Efficiency at 5V_OUT
100
95
90
85
80
75
70
65
60
f_SW = 700kHz
55
V_IN = 12V
V_IN = 24V
50
0 0.25 0.5 0.75 1.0 1.25 1.5 1.75 2.0
LOAD CURRENT (A)
8620 TA01b
For more information www.linear.com/LT8620
8620fa
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