Datasheet

2
LTC3718
3718fa
(Note 1)
Input Supply Voltage (V
IN2
) .......................10V to –0.3V
Boosted Topside Driver Supply Voltage
(BOOST) ............................................... 42V to –0.3V
V
IN1
, I
ON
, SW1 Voltage ............................. 36V to –0.3V
RUN/SS, PGOOD Voltages......................... 7V to –0.3V
V
ON
, V
REF
, V
RNG
Voltages .......(INTV
CC
+ 0.3V) to –0.3V
I
TH
, V
FB1
Voltages .................................... 2.7V to –0.3V
SW2 Voltage ............................................. 36V to –0.4V
V
FB2
Voltage .................................................V
IN2
+ 0.3V
SHDN Voltage ......................................................... 10V
TG, BG, INTV
CC
Peak Currents.................................. 2A
TG, BG, INTV
CC
RMS Currents ............................ 50mA
Operating Ambient Temperature
Range (Note 4) ................................... –40°C to 85°C
Junction Temperature (Note 2)............................ 125°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LTC3718EG
T
JMAX
= 125°C, θ
JA
= 130°C/W
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are T
A
= 25°C. V
IN1
= 15V, V
IN2
= 1.5V unless otherwise noted.
ABSOLUTE AXI U RATI GS
WWWU
PACKAGE/ORDER I FOR ATIO
UU
W
ELECTRICAL CHARACTERISTICS
1
2
3
4
5
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9
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12
TOP VIEW
G PACKAGE
24-LEAD PLASTIC SSOP
24
23
22
21
20
19
18
17
16
15
14
13
RUN/SS
V
ON
PGOOD
V
RNG
I
TH
SGND1
I
ON
V
FB1
V
REF
SHDN
SGND2
V
FB2
BOOST
TG
SW1
SENSE
+
SENSE
–
PGND1
BG
INTV
CC
V
IN1
V
IN2
PGND2
SW2
Consult LTC Marketing for parts specified with wider operating temperature ranges.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Buck Regulator
I
Q(VIN1)
Input DC Supply Current (V
IN1
)
Normal 1000 2000 µA
Shutdown Supply Current V
RUN/SS
= 0V 15 30 µA
V
FB1
Feedback Voltage Accuracy I
TH
= 1.2V (Note 3) ● –0.65 0.1 0.65 %
∆V
FB1(LINE)
Feedback Voltage Line Regulation V
IN1
= 4V to 36V, I
TH
= 1.2V (Note 3) 0.002 %/V
∆V
FB1(LOAD)
Feedback Voltage Load Regulation I
TH
= 0.5V to 1.9V (Note 3) ● –0.05 –0.3 %
g
m(EA)
Error Amplifier Transconductance I
TH
= 1.2V (Note 3) 0.93 1.13 1.33 mS
t
ON
On-Time I
ON
= 60µA, V
ON
= 1.5V 200 250 300 ns
I
ON
= 30µA, V
ON
= 1.5V 400 500 600 ns
t
ON(MIN)
Minimum On-Time I
ON
= 180µA 50 100 ns
t
OFF(MIN)
Minimum Off-Time 300 400 ns
V
SENSE(MAX)
Maximum Current Sense Threshold V
RNG
= 1V, V
FB1
= V
REF
/2 – 50mV ● 108 135 162 mV
V
PGND
– V
SW1
(Source) V
RNG
= 0V, V
FB1
= V
REF
/2 – 50mV ● 76 95 114 mV
V
RNG
= INTV
CC
, V
FB1
= V
REF
/2 – 50mV ● 148 185 222 mV
V
SENSE(MIN)
Minimum Current Sense Threshold V
RNG
= 1V, V
FB1
= V
REF
/2 + 50mV –140 –165 –190 mV
V
PGND
– V
SW1
(Sink) V
RNG
= 0V, V
FB1
= V
REF
/2 + 50mV –97 –115 –133 mV
V
RNG
= INTV
CC
, V
FB1
= V
REF
/2 + 50mV –200 –235 –270 mV
∆V
FB1(OV)
Output Overvoltage Fault Threshold 8 10 12 %
∆V
FB1(UV)
Output Undervoltage Fault Threshold –25 %
V
RUN/SS(ON)
RUN Pin Start Threshold ● 0.8 1.5 2 V
V
RUN/SS(LE)
RUN Pin Latchoff Enable RUN/SS Pin Rising 4 4.5 V