Rainbow Electronics LM27 - Manual (Page 4)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed
specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test
conditions.
Note 2: When the input voltage (V I ) at any pin exceeds the power supply (V I
< GND or V I
> V + ), the current at that pin should be limited to 5mA. The 20mA
maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 5mA to four. Under normal
operating conditions the maximum current that pins 2, 4 or 5 can handle is limited to 5mA each.
Note 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by T Jmax (maximum junction temperature), θ
JA (junction to
ambient thermal resistance) and T A (ambient temperature). The maximum allowable power dissipation at any temperature is P D = (T Jmax –T A )/ θ
JA or the number
given in the Absolute Maximum Ratings, whichever is lower. For this device, T Jmax = 150˚C. For this device the typical thermal resistance ( θ
JA ) of the different
package types when board mounted follow:
Package Type θ
JA
SOT23-5, MA05B 250˚C/W
Note 4: The human body model is a 100pF capacitor discharge through a 1.5k Ω resistor into each pin. The machine model is a 200pF capacitor discharged directly
into each pin.
Note 5: See the URL ”http://www.national.com/packaging/“ for other recommendations and methods of soldering surface mount devices.
Note 6: Typicals are at T
J
= T
A
= 25˚C and represent most likely parametric norm.
Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 8: Care should be taken to include the effects of self heating when setting the maximum output load current. The power dissipation of the LM27 would increase
by 1.28mW when I
OUT
=3.2mA and V
OUT
=0.4V. With a thermal resistance of 250˚C/W, this power dissipation would cause an increase in the die temperature of
about 0.32˚C due to self heating. Self heating is not included in the trip point accuracy specification.
Note 9: The 1µA limit is based on a testing limitation and does not reflect the actual performance of the part. Expect to see a doubling of the current for every 15˚C
increase in temperature. For example, the 1nA typical current at 25˚C would increase to 16nA at 85˚C.
Part Number Template
The series of digits labeled xyz in the part number LM27CIM-xyz, describe the set point value and the function of the output as
follows:
The place holders xy describe the set point temperature as shown in the following table.
x (10x) y (1x) Temperature (˚C)
- H 0
- J 1
- K 2
- L 3
- N 4
- P 5
- R 6
x (10x) y (1x) Temperature (˚C)
- S 7
- T 8
- V 9
Z - 12
1 - 13
2 - 14
3 - 15
The value of z describes the assignment/function of the output as shown in the following table:
Active-Low/High
Open-Drain/
Push-Pull OS/US Value of z Digital Output Function
0 0 0 J Active-Low, Open-Drain, OS output
0 0 1 K Active-Low, Open-Drain, US output
1 1 0 L Active-High, Push-Pull, OS output
1 1 1 N Active-High, Push-Pull, US output
For example:
• the part number LM27CIM5-2SJ has T
OS
= 147˚C, and programmed as an active-low open-drain overtemperature shutdown
output.
• the part number LM27CIM5-ZLN has T
US
= 123˚C, and programmed as an active-high, push-pull undertemperature shutdown
output.
Active-high open-drain and active-low push-pull options are available, please contact National Semiconductor for more informa-
tion.
LM27
www.national.com 4