LT1977 Linear Technology, LT1977 Datasheet - Page 2

• Manufacturer Part Number: LT1977
• Description: Step-Down Switching Regulator
• Manufacturer: Linear Technology

ABSOLUTE AXI U RATI GS
LT1977
(Note 1)
V
BOOST Pin Above SW ............................................ 35V
BOOST Pin Voltage ................................................. 68V
SYNC, C
Operating JunctionTemperature Range
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
temperature range, otherwise specifications are at T
unless otherwise noted.
SYMBOL
V
I
I
I
I
I
V
I
I
2
ELECTRICAL CHARACTERISTICS
SHDN
VINS
VIN
BIASS
BIAS
FB
PK
SHDN
REF
IN
LT1977EFE (Note 2) ........................ – 40°C to 125°C
LT1977IFE (Note 2) ......................... – 40°C to 125°C
, SHDN, BIAS ..................................................... 60V
SS
PARAMETER
SHDN Threshold
SHDN Input Current
Minimum Input Voltage (Note 3)
Supply Shutdown Current
Supply Sleep Current (Note 4)
Supply Quiescent Current
Minimum BIAS Voltage (Note 5)
BIAS Sleep Current (Note 4)
BIAS Quiescent Current
Minimum Boost Voltage (Note 6)
Input Boost Current (Note 7)
Reference Voltage (V
FB Input Bias Current
EA Voltage Gain (Note 8)
EA Voltage g
EA Source Current
EA Sink Current
V
V
SW Current Limit
C
C
, PGFB, FB ................................................ 6V
to SW g
High Clamp
m
W
m
REF
W W
)
U
CONDITIONS
SHDN = 12V
SHDN = 0V, BOOST = 0V, FB/PGFB = 0V
BIAS = 0V, FB = 1.35V
FB = 1.35V
BIAS = 0V, FB = 1.15V
BIAS = 5V, FB = 1.15V
SYNC = 3.3V
I
I
3.3V < V
dI(V
FB = 1.15V
FB = 1.35V
SW
SW
J
= 25°C. V
= 1.5A
= 1.5A
C
)= ±10µA
The
VIN
< 60V
●
IN
denotes the specifications which apply over the full operating
= 12V, SHDN = 12V, BIAS = 5V, FB/PGFB = 1.25V, C
PACKAGE/ORDER I FOR ATIO
Consult LTC Marketing for parts specified with wider operating temperature ranges.
T
JMAX
BOOST
GND
MUST BE SOLDERED TO GND (PIN 8)
= 125°C, θ
SW
V
NC
NC
NC
C
IN
EXPOSED PAD IS GND (PIN 17)
T
16-LEAD PLASTIC TSSOP
1
2
3
4
5
6
7
8
JA
FE PACKAGE
= 45°C/W, θ
TOP VIEW
17
JC(PAD)
●
●
●
●
●
●
●
●
16
15
14
13
12
11
10
9
= 10°C/W
1.225
1.15
MIN
450
PG
SHDN
SYNC
PGFB
FB
V
BIAS
C
2.1
1.5
20
15
C
SS
U
1.25
TYP
170
110
700
900
650
1.3
2.4
0.1
2.7
1.8
2.2
2.4
40
45
40
75
30
5
3
ORDER PART
LT1977EFE
LT1977IFE
W
SS
MARKING
NUMBER
FE PART
1977EFE
1977IFE
/SYNC = 0V
1.275
MAX
1.45
4.10
3.25
250
180
900
200
900
2.4
3.5
20
75
55
40
3
2
3
UNITS
µMho
U
1977f
A/V
V/V
mA
mA
mA
µA
µA
µA
µA
µA
µA
nA
µA
µA
V
V
V
V
V
V
A