LTC1778/LTC1778-1
ABSOLUTE AXI U RATI GS (Note 1)
Input Supply Voltage (VIN, ION)................. 36V to – 0.3V
Boosted Topside Driver Supply Voltage
(BOOST) ................................................... 42V to – 0.3V
SW Voltage .................................................. 36V to – 5V
EXTVCC, (BOOST – SW), RUN/SS,
PGOOD Voltages ....................................... 7V to – 0.3V
FCB, VON, VRNG Voltages .......... INTVCC + 0.3V to – 0.3V
ITH, VFB Voltages...................................... 2.7V to – 0.3V
TG, BG, INTVCC, EXTVCC Peak Currents .................... 2A
TG, BG, INTVCC, EXTVCC RMS Currents .............. 50mA
Operating Ambient Temperature Range (Note 4)
LTC1778E ........................................... – 40°C to 85°C
LTC1778I .......................................... – 40°C to 125°C
Junction Temperature (Note 2) ............................ 125°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
UW U
PACKAGE/ORDER I FOR ATIO
TOP VIEW
RUN/SS 1
PGOOD 2
VRNG 3
FCB 4
ITH 5
SGND 6
ION 7
VFB 8
16 BOOST
15 TG
14 SW
13 PGND
12 BG
11 INTVCC
10 VIN
9 EXTVCC
GN PACKAGE
16-LEAD PLASTIC SSOP
TJMAX = 125°C, θJA = 130°C/ W
ORDER PART
NUMBER
LTC1778EGN
LTC1778IGN
GN PART MARKING
1778
1778I
Consult LTC Marketing for parts specified with wider operating temperature ranges.
TOP VIEW
RUN/SS 1
VON 2
VRNG 3
FCB 4
ITH 5
SGND 6
ION 7
VFB 8
16 BOOST
15 TG
14 SW
13 PGND
12 BG
11 INTVCC
10 VIN
9 EXTVCC
GN PACKAGE
16-LEAD PLASTIC SSOP
TJMAX = 125°C, θJA = 130°C/ W
ORDER PART
NUMBER
LTC1778EGN-1
GN PART MARKING
17781
ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are TA = 25°C. VIN = 15V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX
Main Control Loop
IQ
Input DC Supply Current
Normal
Shutdown Supply Current
900 2000
15
30
VFB
Feedback Reference Voltage
∆VFB(LINEREG)
∆VFB(LOADREG)
IFB
gm(EA)
VFCB
IFCB
tON
Feedback Voltage Line Regulation
Feedback Voltage Load Regulation
Feedback Input Current
Error Amplifier Transconductance
Forced Continuous Threshold
Forced Continuous Pin Current
On-Time
tON(MIN)
Minimum On-Time
ITH = 1.2V (Note 3) LTC1778E
ITH = 1.2V (Note 3) LTC1778I
VIN = 4V to 30V, ITH = 1.2V (Note 3)
ITH = 0.5V to 1.9V (Note 3)
VFB = 0.8V
ITH = 1.2V (Note 3)
VFCB = 0.8V
ION = 30µA, VON = 0V (LTC1778-1)
ION = 15µA, VON = 0V (LTC1778-1)
ION = 180µA
● 0.792
● 0.792
●
● 1.4
● 0.76
198
396
0.800
0.800
0.002
– 0.05
–5
1.7
0.8
–1
233
466
50
0.808
0.812
– 0.3
±50
2
0.84
–2
268
536
100
2
UNITS
µA
µA
V
V
%/V
%
nA
mS
V
µA
ns
ns
ns
1778fb