LT1175
elecTrical characTerisTics
Note 8: Thermal regulation is a change in the output voltage caused by
die temperature gradients, so it is proportional to chip power dissipation.
Temperature gradients reach final value in less than 100ms. Output voltage
changes after 100ms are due to absolute die temperature changes and
reference voltage temperature coefficient.
regulation will be affected by thermal regulation (Note 8) and chip
temperature changes. Load regulation specification also holds for currents
up to the specified current limit when I or I are left open.
Note 11: Current limit is reduced for input-to-output voltage above 12V.
See the graph in Typical Performance Characteristics for guaranteed limits
above 12V.
Note 12: Operating at very large input-to-output differential voltages
(>15V) with load currents less than 5mA requires an output capacitor with
an ESR greater than 1Ω to prevent low level output oscillations.
LIM2
LIM4
Note 9: The lower limit of 0.8V is guaranteed to keep the regulator in
shutdown. The upper limit of 2.5V is guaranteed to keep the regulator
active. Either polarity may be used, referenced to GND pin.
Note 10: Load and line regulation are measured on a pulse basis with
pulse width of 20ms or less to keep chip temperature constant. DC
Typical perForMance characTerisTics
Typical Current Limit
Characteristics
Guaranteed Current Limit
Output Voltage Temperature Drift
1.0
0.8
0.6
0.4
0.2
0
0.6
0.5
0.4
0.3
0.2
0.1
0
5.05
5.00
4.95
3.84
3.80
3.76
CURRENT LIMIT CHANGES ONLY SLIGHTLY
WITH TEMPERATURE SO CURVES ARE
REPRESENTATIVE OF ALL TEMPERATURES
CURVES REPRE-
SENT MINIMUM
GUARANTEED
I
, I
TIED TO V
OUTPUT
LIM2 LIM4 IN
FIXED 5V PART
LIMITS AT ALL
TEMPERATURES
I
, I
TIED TO V
LIM2 LIM4 IN
I
TIED TO V
LIM4
IN
I
TIED TO V
LIM4
IN
I
TIED TO V
LIM2
IN
I
TIED TO V
LIM2
IN
FEEDBACK VOLTAGE
ADJUSTABLE PART
I
, I
OPEN
LIM2 LIM4
I
, I
OPEN
LIM2 LIM4
0
5
10
15
20
25
0
5
10
15
20
25
50
JUNCTION TEMPERATURE (°C)
125
–50
0
25
75 100
–25
INPUT-TO-OUTPUT DIFFERENTIAL VOLTAGE (V)
INPUT-TO-OUTPUT DIFFERENTIAL VOLTAGE (V)
1175 G03
1175 G01
1175 G02
SENSE Bias Current
(Adjustable Part)
Minimum Input-to-Output Voltage
Minimum Input-to-Output Voltage
1.0
0.8
0.6
0.4
0.2
0
1.0
0.8
0.6
0.4
0.2
0
100
80
60
40
20
0
T = 25°C
V
REDUCED UNTIL OUTPUT
IN
J
IN
V
REDUCED
VOLTAGE DROPS 1%.
I , I TIED TO V
LIM2 LIM4
UNTIL OUTPUT
VOLTAGE
IN
I
TIED
IN
LIM2
DROPS 1%
TO V
I
, I
LIM2 LIM4
T = 125°C
J
OPEN
I
TIED
IN
LIM4
TO V
T = 25°C
J
T = –55°C
J
I
, I
LIM2 LIM4
TIED TO V
IN
0
0.2 0.3 0.4
0.5 0.6 0.7
0
0.2 0.3 0.4
0.5 0.6 0.7
–50
0
25
50
75 100 125
0.1
0.1
–25
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
TEMPERATURE (°C)
1175 G04
1175 G05
1175 G06
1175fe
ꢄ
Linear [ Linear ]
