Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
VIN Pin: Voltage to GND
FB, SW, EN Pin:
Continuous Power Dissipation
Junction Temperature (TJ-MAX)
Storage Temperature Range
Maximum Lead Temperature
(Soldering, 10 sec.)
ESD Rating (Note 4)
−0.2V to 6.0V
(VIN + 0.2V)
−65°C to +150°C
Human Body Model
Operating Ratings (Notes 1, 2)
Input Voltage Range (Note 10)
Recommended Load Current
Junction Temperature (TJ) Range
Ambient Temperature (TA) Range (Note
2.7V to 5.5V
0mA to 350 mA
−30°C to +125°C
−30°C to +85°C
Resistance (θJA) (MicroSMD)
for 4 layer board (Note 6)
Electrical Characteristics (Notes 2, 8, 9) Limits in standard typeface are for TJ = 25°C. Limits in boldface type
apply over the full operating ambient temperature range (−30°C ≤ TA ≤ +85°C). Unless otherwise noted, specifications apply to
the LM3673TL with VIN = EN = 3.6V
Min Typ Max Units
Feedback Voltage (Fixed / ADJ) TL
Internal Reference Voltage
Shutdown Supply Current
DC Bias Current into VIN
PWM mode (Note 11)
2.7V ≤ VIN ≤ 5.5V
IO = 20 mA
150 mA ≤ IO ≤ 350 mA
EN = 0V
No load, device is not switching (FB
forced higher than programmed
Pin-Pin Resistance for PFET
Pin-Pin Resistance for NFET
Switch Peak Current Limit
Logic High Input
Logic Low Input
Enable (EN) Input Current
Internal Oscillator Frequency
VIN= VGS= 3.6V
VIN= VGS= 3.6V
Open Loop (Note 7)
PWM Mode (Note 11)
350 450 mΩ
150 250 mΩ
590 750 855 mA
0.01 1 µA
1.6 2 2.6 MHz
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. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see
the Electrical Characteristics tables.
Note 2: All voltages are with respect to the potential at the GND pin.
Note 3: Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ= 150°C (typ.) and disengages at
TJ= 130°C (typ.).
Note 4: The Human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200 pF capacitor discharged
directly into each pin. MIL-STD-883 3015.7
Note 5: In Applications where high power dissipation and/or poor package resistance is present, the maximum ambient temperature may have to be derated.
Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX), the maximum power dissipation of the device in
the application (PD-MAX) and the junction to ambient thermal resistance of the package (θJA) in the application, as given by the following equation:TA-MAX= TJ-MAX
− (θJAx PD-MAX). Refer to Dissipation rating table for PD-MAX values at different ambient temperatures.
Note 6: Junction to ambient thermal resistance is highly application and board layout dependent. In applications where high power dissipation exists, special care
must be given to thermal dissipation issues in board design. Specified value of 85 °C/W for µSMD is based on a 4 layer, 4" x 3", 2/1/1/2 oz. Cu board as per
JEDEC standards is used.
Note 7: Refer to datasheet curves for closed loop data and its variation with regards to supply voltage and temperature. Electrical Characteristic table reflects
open loop data (FB=0V and current drawn from SW pin ramped up until cycle by cycle current limit is activated). Closed loop current limit is the peak inductor
current measured in the application circuit by increasing output current until output voltage drops by 10%.
Note 8: Min and Max limits are guaranteed by design, test or statistical analysis. Typical numbers are not guaranteed, but do represent the most likely norm.
Note 9: The parameters in the electrical characteristic table are tested at VIN= 3.6V unless otherwise specified. For performance over the input voltage range
refer to datasheet curves.