LM2598S-ADJ National Semiconductor, LM2598S-ADJ Datasheet - Page 5

• Manufacturer Part Number: LM2598S-ADJ
• Description: SIMPLE SWITCHER Power Converter 150 kHz 1A Step-Down Voltage Regulator/ with Features
• Manufacturer: National Semiconductor

SHUTDOWN/SOFT-START CONTROL Test Circuit of Figure 1
I
I
FLAG/DELAY CONTROL Test Circuit of Figure 1
VF
IF
Symbol
SD
SS
Specifications with standard type face are for T
Range. Unless otherwise specified, V
I
All Output Voltage Versions
Electrical Characteristics
LOAD
L
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is in-
tended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.
Note 2: Voltage internally clamped. If clamp voltage is exceeded, limit current to a maximum of 1 mA.
Note 3: The human body model is a 100 pF capacitor discharged through a 1.5k resistor into each pin.
Note 4: Typical numbers are at 25˚C and represent the most likely norm.
Note 5: All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). All room temperature limits are 100% pro-
duction tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to cal-
culate Average Outgoing Quality Level (AOQL).
Note 6: External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2598
is used as shown in the Figure 1 test circuit, system performance will be as shown in system parameters section of Electrical Characteristics.
Note 7: The switching frequency is reduced when the second stage current limit is activated. The amount of reduction is determined by the severity of current over-
load.
Note 8: No diode, inductor or capacitor connected to output pin.
Note 9: Feedback pin removed from output and connected to 0V to force the output transistor switch ON.
Note 10: 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.
Note 11: V
Note 12: Junction to ambient thermal resistance (no external heat sink) for the TO-220 package mounted vertically, with the leads soldered to a printed circuit board
with (1 oz.) copper area of approximately 1 in
Note 13: Junction to ambient thermal resistance with the TO-263 package tab soldered to a single sided printed circuit board with 0.5 in
Note 14: Junction to ambient thermal resistance with the TO-263 package tab soldered to a single sided printed circuit board with 2.5 in
Note 15: Junction to ambient thermal resistance with the TO-263 package tab soldered to a double sided printed circuit board with 3 in
the LM2598S side of the board, and approximately 16 in
in Switchers Made Simple
SAT
= 200 mA
IN
Shutdown Current
Soft-start Current
Regulator Dropout Detector
Threshold Voltage
Flag Output Saturation
Voltage
Flag Output Leakage
Current
Delay Pin Threshold
Voltage
Delay Pin Source Current
Delay Pin Saturation
= 40V.
Parameter
®
version 4.2 software.
2
.
IN
= 12V for the 3.3V, 5V, and Adjustable version and V
V
V
Low (Flag ON)
I
V
V
Low (Flag ON)
High (Flag OFF) and V
V
Low (Flag ON)
SINK
SHUTDOWN
Soft-start
DELAY
FLAG
DELAY
(Continued)
2
of copper on the other side of the p-c board. See application hints in this data sheet and the thermal model
= 3 mA
J
= 40V
= 25˚C, and those with boldface type apply over full Operating Temperature
= 0.5V
= 0.5V
= 2.5V
= 0.5V
Conditions
5
OUT
Regulated
(Note 4)
IN
1.25
Typ
1.6
0.3
0.3
96
55
= 24V for the 12V version.
5
3
LM2598-XX
(Note 5)
2
350/400
0.7/1.0
2
2
of (1 oz.) copper area on
Limit
1.21
1.29
of (1 oz.) copper area.
of (1 oz.) copper area.
10
92
98
5
6
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mV(max)
µA(max)
µA(max)
µA(max)
(Limits)
%(max)
%(min)
V(max)
V(max)
V(min)
Units
mV
µA
µA
µA
µA
%
V
V