Datasheet

2
LT1111
1111fd
A
U
G
W
A
W
U
W
ARB
S
O
LU
T
EXI T
I
S
Operating Temperature Range
LT1111C............................................... 0°C to 70°C
LT1111I......................................... –40°C to 105°C
LT1111M (OBSOLETE) ............. –55°C to 125°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
WU
U
PACKAGE
/
O
RDER I FOR ATIO
Supply Voltage (V
IN
)............................................... 36V
SW1 Pin Voltage (V
SW1
)......................................... 50V
SW2 Pin Voltage (V
SW2
)............................ –0.5V to V
IN
Feedback Pin Voltage (LT1111) ............................. 5.5V
Switch Current....................................................... 1.5A
Maximum Power Dissipation ............................ 500mW
ORDER PART
NUMBER
LT1111CN8
LT1111CN8-5
LT1111CN8-12
ORDER PART
NUMBER
LT1111CS8
LT1111CS8-5
LT1111CS8-12
LT1111IS8
T
JMAX
= 90°C, θ
JA
= 130°C/W (N)
1
2
3
4
8
7
6
5
TOP VIEW
I
LIM
V
IN
SW1
SW2
FB (SENSE)*
SET
A0
GND
N8 PACKAGE
8-LEAD PLASTIC DIP
*FIXED VERSIONS
T
JMAX
= 90°C, θ
JA
= 150°C/W
1
2
3
4
8
7
6
5
TOP VIEW
FB (SENSE)*
SET
A0
GND
I
LIM
V
IN
SW1
SW2
S8 PACKAGE
8-LEAD PLASTIC SO
*FIXED VERSION
E
LECTR
IC
AL C CHARA TERIST
ICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C.V
IN
= 3V, Military or Commercial Version
S8 PART MARKING
1111
11115
11111
1111I
(Note 1)
LT1111MJ8
LT1111MJ8-5
LT1111MJ8-12
J8 PACKAGE
8-LEAD CERAMIC DIP
T
JMAX
= 150°C, θ
JA
= 120°C/W (J)
Consult LTC Marketing for parts specified with wider operating temperature ranges.
OBSOLETE PACKAGE
Consider the N8 Package for Alternate Source
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
Q
Quiescent Current Switch OFF 300 400 µA
V
IN
Input Voltage Step-Up Mode ● 2.0 12.6 V
Step-Down Mode
● 30.0 V
Comparator Trip Point Voltage LT1111 (Note 2) ● 1.20 1.25 1.30 V
V
OUT
Output Sense Voltage LT1111-5 (Note 3 ● 4.75 5.00 5.25 V
LT1111-12 (Note 3)
● 11.40 12.00 12.60 V
Comparator Hysteresis LT1111 ● 8 12.5 mV
Output Hysteresis LT1111-5 ● 32 50 mV
LT1111-12
● 75 120 mV
f
OSC
Oscillator Frequency 54 72 88 kHz
DC Duty Cycle: Step-Up Mode Full Load 43 50 59 %
Step-Down Mode 24 34 50 %
t
ON
Switch ON Time: Step-Up Mode I
LIM
Tied to V
IN
579 µs
Step-Down Mode V
OUT
, = 5V, V
IN
= 12V 3.3 5 7.8 µs
V
SAT
SW Saturation Voltage, Step-Up Mode V
IN
= 3.0V, I
SW
= 650mA 0.5 0.65 V
V
IN
= 5.0V, I
SW
= 1A 0.8 1.0 V
SW Saturation Voltage, Step-Down Mode V
IN
= 12V, I
SW
= 650mA 1.1 1.5 V