SNVS434M July   2006  – November 2016 LM3673

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Voltage Options
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Ratings
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Circuit Operation
      2. 8.3.2 PWM Operation
      3. 8.3.3 Internal Synchronous Rectification
      4. 8.3.4 Current Limiting
      5. 8.3.5 Soft Start
      6. 8.3.6 Low Drop Out Operation (LDO)
    4. 8.4 Device Functional Modes
      1. 8.4.1 PFM Operation
      2. 8.4.2 Shutdown Mode
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Output Voltage Selection for LM3673-ADJ
        2. 9.2.2.2 Inductor Selection
          1. 9.2.2.2.1 Method 1
          2. 9.2.2.2.2 Method 2
        3. 9.2.2.3 Input Capacitor Selection
        4. 9.2.2.4 Output Capacitor Selection
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 DSBGA Package Assembly and Use
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7 Specifications

7.1 Absolute Maximum Ratings(1)(2)

MIN MAX UNIT
VIN pin: voltage to GND –0.2 6 V
FB, SW, EN pins GND−0.2 (VIN + 0.2 V
Continuous power dissipation(3) Internally Limited
Junction temperature, TJ-MAX 125 °C
Maximum lead temperature  (soldering, 10 sec.) 260 °C
Storage temperature, Tstg –65 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) If Military/Aerospace specified devices are required, contact the TI Sales Office/Distributors for availability and specifications.
(3) Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ= 150°C (typical) and disengages at TJ= 130°C (typical).

7.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V
Machine model ±200
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.

7.3 Recommended Operating Ratings

over operating free-air temperature range (unless otherwise noted)(1)(2)
MIN NOM MAX UNIT
Input voltage(3) 2.7 5.5 V
Recommended load current 0 350 mA
Junction temperature, TJ –30 125 °C
Ambient temperature, TA(4) –30 85 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) All voltages are with respect to the potential at the GND pin.
(3) The input voltage range recommended for ideal applications performance for the specified output voltages are as follows: VIN = 2.7 V to 4.5 V for 1.1 V ≤ VOUT < 1.5 V; VIN = 2.7 V to 5.5 V for 1.5 V ≤ VOUT < 1.8 V; VIN = (VOUT + VDROPOUT) to 5.5 V for 1.8 V ≤ VOUT ≤ 3.3 V where VDROPOUT = ILOAD × (RDSON, PFET + RINDUCTOR)
(4) 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 (RθJA) in the application, as given by the following equation:TA-MAX = TJ-MAX− (RθJA × PD-MAX).

7.4 Thermal Information

THERMAL METRIC(1) LM3673 UNIT
YZR (DSBGA)
5 PINS
RθJA Junction-to-ambient thermal resistance(2) 181.0 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 0.9 °C/W
RθJB Junction-to-board thermal resistance 110.3 °C/W
ψJT Junction-to-top characterization parameter 7.4 °C/W
ψJB Junction-to-board characterization parameter 110.3 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics.
(2) 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.

7.5 Electrical Characteristics

Typical limits apply for TJ = 25°C. Unless otherwise specified, minimum and maximum limits apply over the full operating ambient temperature range (−30°C ≤ TA ≤ +85°C). Unless otherwise noted, specifications apply to the LM3673TL with VIN = EN = 3.6 V.(1)(2)(3)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
VIN Input voltage See(4) 2.7 5.5 V
VFB Feedback voltage (fixed / ADJ) PWM mode(5) –2.5% 2.5%
Line regulation 2.7 V ≤ VIN ≤ 5.5 V
IOUT = 20 mA		 0.025 %/V
Load regulation 150 mA ≤ IOUT ≤ 350 mA
VIN= 3.6 V		 0.0015 %/mA
VREF Internal reference voltage 0.5 V
ISHDN Shutdown supply current EN = 0V 0.01 1 µA
IQ DC bias current into VIN No load, device is not switching (FB forced higher than programmed output voltage) 16 35 µA
RDSON (P) Pin-pin resistance for PFET VIN= VGS= 3.6 V, TA = 25°C 350 450 mΩ
RDSON (N) Pin-pin resistance for NFET VIN= VGS= 3.6 V, TA = 25°C 150 250 mΩ
ILIM Switch peak current limit Open loop(6) 590 750 855 mA
VIH Logic high input 1 V
VIL Logic low input 0.4 V
IEN Enable (EN) input current 0.01 1 µA
ƒOSC Internal oscillator frequency PWM mode(5) 1.6 2 2.6 MHz
(1) All voltages are with respect to the potential at the GND pin.
(2) Minimum and maximum limits are specified by design, test or statistical analysis. Typical numbers are not verified, but do represent the most likely norm.
(3) The parameters in the electrical characteristic table are tested at VIN= 3.6 V unless otherwise specified. For performance over the input voltage range refer to datasheet curves.
(4) The input voltage range recommended for ideal applications performance for the specified output voltages are as follows: VIN = 2.7 V to 4.5 V for 1.1 V ≤ VOUT < 1.5 V; VIN = 2.7 V to 5.5 V for 1.5 V ≤ VOUT < 1.8 V; VIN = (VOUT+ VDROPOUT) to 5.5 V for 1.8 V ≤ VOUT ≤ 3.3 V, where VDROPOUT = ILOAD × (RDSON, PFET + RINDUCTOR).
(5) Test condition: for VOUT less than 2.5 V, VIN = 3.6 V; for VOUT greater than or equal to 2.5 V, VIN = VOUT + 1 V.
(6) Refer to for closed-loop data and its variation with regards to supply voltage and temperature. Electrical Characteristics reflects open-loop data (FB = 0 V 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%.

7.6 Typical Characteristics

LM3673TL typical application (Figure 17), VIN = 3.6 V, VOUT= 1.5 V, TA = 25°C, unless otherwise noted.
LM3673 20183304.gif Figure 1. Quiescent Supply Current vs. Supply Voltage
LM3673 20183340.png Figure 3. Feedback Bias Current vs. Temperature
LM3673 20183333.gif Figure 5. RDSON vs. Temperature
LM3673 20183329.gif
VOUT = 1.5 V
Figure 7. Output Voltage vs. Supply Voltage
LM3673 20183359.png
VOUT = 1.5 V
Figure 9. Output Voltage vs. Output Current
LM3673 20183355.png
VOUT = 1.5 V (PWM to PFM)
Figure 11. Mode Change by Load Transients
LM3673 20183356.png
VOUT = 1.5 V Output Current= 5 mA
Figure 13. Start-Up into PFM Mode
LM3673 20183305.gif Figure 2. Shutdown Current vs. Temperature
LM3673 20183347.png Figure 4. Switching Frequency vs. Temperature
LM3673 20183348.gif Figure 6. Open/Closed Loop Current Limit vs. Temperature
LM3673 20183306.gif
VOUT = 1.5 V
Figure 8. Output Voltage vs. Temperature
LM3673 20183354.png
VOUT = 1.5 V (PFM to PWM)
Figure 10. Mode Change by Load Transients
LM3673 20183324.png
VOUT = 1.5 V Output Current= 150 mA
Figure 12. Start-Up into PWM Mode