LM2597, LM2597HV
SNVS119C –MARCH 1998–REVISED APRIL 2013
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All Output Voltage Versions
Electrical Characteristics
Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating
Temperature Range. Unless otherwise specified, VIN = 12V for the 3.3V, 5V, and Adjustable version and VIN = 24V for the
12V version. ILOAD = 100 mA.
Symbol
Parameter
Conditions
LM2597/LM2597HV-XX
Units
(Limits)
(1)
(2)
Typ
Limit
DEVICE PARAMETERS
Ib
Feedback Bias Current
Adjustable Version Only, VFB = 1.235V
10
50/100
nA
kHz
(3)
fO
Oscillator Frequency
See
150
0.9
127/110
173/173
kHz(min)
kHz(max)
V
(4)(5)
VSAT
DC
Saturation Voltage
IOUT = 0.5A
1.1/1.2
V(max)
%
(5)
Max Duty Cycle (ON)
Min Duty Cycle (OFF)
See
100
0
(6)
See
(4)(5)
ICL
Current Limit
Peak Current
0.8
A
A(min)
A(max)
μA(max)
mA
0.65/0.58
1.3/1.4
50
(4)(6)(7)
IL
Output Leakage Current
Output = 0V
Output = −1V
2
5
15
10
mA(max)
mA
(6)
IQ
Operating Quiescent
Current
SD /SS Pin Open, VBS Pin Open
mA(max)
μA
ISTBY
Standby Quiescent
Current
SD /SS pin = 0V (6) LM2597
85
200/250
250/300
μA(max)
μA(max)
°C/W
LM2597HV
140
95
(8)
θJA
Thermal Resistance
P Package, Junction to Ambient
(8)
D Package, Junction to Ambient
150
SHUTDOWN/SOFT-START CONTROL Test Circuit of Figure 31
VSD
Shutdown Threshold
Voltage
1.3
V
Low, (Shutdown Mode)
0.6
2
V(max)
V(min)
V
High, (Soft-start Mode)
VSS
ISD
ISS
Soft-start Voltage
Shutdown Current
Soft-start Current
VOUT = 20% of Nominal Output Voltage
VOUT = 100% of Nominal Output Voltage
VSHUTDOWN = 0.5V
2
3
5
μA
10
5
μA(max)
μA
VSoft-start = 2.5V
1.6
μA(max)
(1) Typical numbers are at 25°C and represent the most likely norm.
(2) All limits specified at room temperature (standard type face) and at temperature extremes (bold type face). All room temperature limits
are 100% production tested. All limits at temperature extremes are specified via correlation using standard Statistical Quality Control
(SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(3) The switching frequency is reduced when the second stage current limit is activated. The amount of reduction is determined by the
severity of current overload.
(4) No diode, inductor or capacitor connected to output pin.
(5) Feedback pin removed from output and connected to 0V to force the output transistor switch ON.
(6) Feedback pin removed from output and connected to 12V for the 3.3V, 5V, and the ADJ. version, and 15V for the 12V version, to force
the output transistor switch OFF.
(7) VIN = 40V for the LM2597 and 60V for the LM2597HV.
(8) Junction to ambient thermal resistance with approximately 1 square inch of printed circuit board copper surrounding the leads. Additional
copper area will lower thermal resistance further. See application hints in this data sheet and the thermal model in Switchers Made
Simple software.
6
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