lm27212 National Semiconductor Corporation, lm27212 Datasheet - Page 8

• Manufacturer Part Number: lm27212
• Description: Two-phase Current-mode Hysteretic Buck Controller
• Manufacturer: National Semiconductor Corporation

www.national.com
Over-voltage Protection
System
Electrical Characteristics
type apply over a junction temperature range of -5˚C to +110˚C. Unless otherwise specified, VDD = 5V, SGND = DGND =
SRCK1 = 0V. (Note 5) (Continued)
Note 1: Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the
device is guaranteed. For guaranteed performance limits and associated test conditions, see the Electrical Characteristics table. Functional temperature range is the
range within which the device performs its intended functions, but not necessarily meeting the limits specified in the Electrical Characteristic table.
Note 2: The maximum allowable power dissipation is calculated by using P
ambient temperature, and θ
for T
dissipation of more power. The Absolute Maximum power dissipation should be de-rated by 12.5mW per ˚C above 25˚C ambient. The LM27212 actively limits its
junction temperature to about 150˚C.
Note 3: For detailed information on soldering plastic small-outline packages, refer to the Packaging Databook available from National Semiconductor Corporation.
Note 4: For testing purposes, ESD was applied using the human-body model, a 100pF capacitor discharged through a 1.5kΩ resistor.
Note 5: All limits are guaranteed at room temperature (standard face type) and at temperature extremes (bold face type). All room temperature limits are 100%
production tested. All limits at temperature extremes are guaranteed via correlation using Statistical Quality Control (SQC) methods. All limits are used to calculate
Average Outgoing Quality Level (AOQL).
Symbol
JMAX
, T
A
, and θ
Power Good Mask For
Dynamic Output Swing
Power Good De-assertion
Delay Upon Shutdown
SENSE Voltage as a
Percentage of VOVP
DE_EN# Input Logic
Low-to-High Transition
Threshold
DE_EN# Input Logic
High-to-Low Transition
Threshold
DE_EN# Pin Leakage Current DE_EN# = 7.5V
Soft Shutdown Finish
Threshold
JA
respectively. The θ
JA
is the junction-to-ambient thermal resistance of the specified package. The 1.56W rating results from using 150˚C, 25˚C, and 80˚C/W
Parameter
JA
of 90˚C/W represents the worst-case condition with no heat sinking of the 48-Pin TSSOP. Heat sinking allows the safe
Specifications with standard typeface are for T
Delay From VRON de-assertion to PGOOD
de-assertion
VOVP = VREF
Dmax
Conditions
8
= (T
JMAX
- T
A
) /θ
JA
, where T
JMAX
J
is the maximum junction temperature, T
= 25˚C, and those in bold face
0.315
Min
100
109
Typ
133
123
0.3
90
Max
0.63
179
139
100
A
Units
is the
µA
µs
ns
%
V
V
V