LT1076-5
3
10765fc
ELECTRICAL CHARACTERISTICS
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: To calculate maximum switch “on” voltage at currents between
low and high conditions, a linear interpolation may be used.
Note 3: A sense pin voltage (V
SENSE
) of 5.5V forces the VC pin to its low
clamp level and the switch duty cycle to zero. This approximates the zero
load condition where duty cycle approaches zero.
Note 4: Total voltage from V
IN
pin to ground pin must be ≥ 8V after start-
up for proper regulation. For T
A
< 25°C, limit = 5V.
Note 5: Switch frequency is internally scaled down when the sense pin
voltage is less than 2.6V to avoid extremely short switch on times. During
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
J
= 25°C. V
IN
= 25V, unless otherwise noted.
current limit testing, V
SENSE
is adjusted to give a minimum switch on time
of 1ms.
Note 6: Switch to input voltage limitation must also be observed.
Note 7: V
MAX
= 40V for the LT1076-5 and 60V for the LT1076HV-5.
Note 8: Error amplifi er voltage gain and transconductance are
specifi ed relative to the internal feedback node. To calculate gain and
transconductance from the Sense pin (Output) to the V
C
pin, multiply by
0.44.
Note 9: Does not include switch leakage.
Note 10:
I
Rk
k
LIM
LIM
≈
− 1
5
SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Current (Note 3) V
OUT
= 5.5V, V
IN
≤ 40V
40V < V
IN
< 60V
V
SHDN
= 0.1V (Device Shutdown) (Note 9)
l
l
8.5
9.0
140
11
12
300
mA
mA
μA
Minimum Supply Voltage Normal Mode
Start-Up Mode (Note 4)
l
l
7.3
3.5
8.0
4.8
V
V
Switch Current Limit (Note 5) I
LIM
= Open
R
LIM
= 10k (Note 10)
R
LIM
= 7k (Note 10)
l
2 2.6
1.8
1.2
3.2 A
A
A
Maximum Duty Cycle
l
85 90 %
Switching Frequency
T
J
≤ 125°C
V
OUT
= V
SENSE
= 0V (Note 5)
l
90
85
100
20
110
120
kHz
kHz
kHz
Switching Frequency Line Regulation 8V ≤ V
IN
≤ V
MAX
(Note 8)
l
0.03 0.1 %/V
Error Amplifi er Voltage Gain (Note 8) 1V ≤ V
C
≤ 4V 2000 V/V
Error Amplifi er Transconductance
(Note 8)
3700 5000 8000 μmho
Error Amplifi er Source and Sink
Current
Source (V
SENSE
= 4.5V)
Sink (V
SENSE
= 5.5V)
100
0.7
140
1.0
225
1.6
μA
mA
Sense Pin Divider Resistance 358 kΩ
Sense Voltage V
C
= 2V
l
4.85 5 5.15 V
Output Voltage Tolerance V
OUT
(Nominal) = 5V
All Conditions of Input Voltage, Output Voltage,
Temperature and Load Current
l
±0.5
±1.0
±2
±3
%
%
Output Voltage Line Regulation 8V ≤ V
IN
≤ V
MAX
(Note 7)
l
0.005 0.02 %/V
VC Voltage at 0% Duty Cycle
Over Temperature
l
1.5
–4.0
V
mV/°C
Multiplier Reference Voltage 24 V
Shutdown Pin Current V
SHDN
= 5V
V
SHDN
≤ V
THRESHOLD
(≅ 2.5V)
51020
50
μA
μA
Shutdown Thresholds Switch Duty Cycle = 0
Fully Shut Down
2.2
0.1
2.45
0.30
2.7
0.5
V
V
Thermal Resistance Junction to Case 4°C/W
