Typicals and limits appearing in regular type apply for T

tion temperature range for operation, 0 to +125˚C. Unless otherwise specified under the Parameter or Conditions columns, V

IN

= 10V, and V

Symbol

Parameter

Conditions

Typical

Limit

Units

Voltage References and Linear Voltage Regulator

V

BG

Bandgap Voltage

1.238

V

V

REF

Reference Voltage

0.01 mA

≤ I

V

2.5

V

2.45

V(min)

2.55

V(max)

V

LIN

Output Voltage of the Linear

Voltage Regulator

6V

≤ V

0mA

≤ I

5V

4.6

V(min)

5.4

V(max)

V

UVLO

Undervoltage Lockout

Threshold

(Note 11)

4.0

V

3.6

V(min)

4.4

V(max)

LIN-to-V

Threshold

V

4.8

V

Logic Inputs

V

IH

Minimum High Level Input

Voltage (SD, ON/OFF1,

ON/OFF2, and SYNC)

2.4

V(min)

V

IH

Minimum High Level Input

Voltage (2NDFB/FPWM)

2.6

V(min)

V

IL

Maximum Low Level Input

Voltage (SD, ON/OFF1,

ON/OFF2, SYNC, and

2NDFB/FPWM)

0.8

V(max)

Maximum Input Leakage

Current (SD, ON/OFF1,

ON/OFF2, and SYNC)

Logic Input Voltage 0 or 5V

µA

Note 1: Unless otherwise specified, all voltages are with respect to the voltage at the GND and PGND pins.

Note 2: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the device

is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical

Characteristics tables.

Note 3: The Absolute Maximum power dissipation depends on the ambient temperature. The 883 mW rating results from substituting 150˚C, 70˚C, and 90.6˚C/W

worst-case condition of no heat sinking of the 28-pin TSSOP. Heat sinking allows the safe dissipation of more power. The Absolute Maximum power dissipation must

be derated by 11.04 mW per ˚C above 70˚C ambient. The LM2641 actively limits its junction temperature to about 150˚C.

Note 4: For detailed information on soldering plastic small-outline packages, refer to the Packaging Databook available from National Semiconductor Corporation.

Note 5: For testing purposes, ESD was applied using the human-body model, a 100 pF capacitor discharged through a 1.5 k

Ω resistor.

guaranteed by correlating the electrical characteristics to process and temperature variations and applying statistical process control.

Note 8: Both controllers are ON but not switching. Currents entering the IC at IN, CSL1, CSH1, CSL2, and CSH2 are measured. Those entering at CSL1 and CSH1

are multiplied by 0.50 to emulate the effect of a switching conversion from 10V down to 5V. Those entering at CSL2 and CSH2 are multiplied by 0.33 to emulate the

effect of a switching conversion from 10V down to 3.3V. After multiplication, all five currents are added. Because the voltage at the CSL1 input is greater than the

Note 9: Both switching controllers are OFF. The 5V, 50 mA linear regulator (output at LIN) and the precision 2.5V reference (output at REF) remain ON.

Note 10: Both switching controllers and the 2.5V precision reference are OFF. The 5V, 50 mA linear regulator remains ON.

Note 11: The controllers remain OFF until the voltage of the 5V, 50 mA linear regulator (output at LIN) reaches this threshold.

Note 12: In applications where the output voltage can exceed the absolute maximum rating, a 100

Ω resistor must be placed in series with the CSH and CSL inputs.

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