SNVS191F November   2002  – October 2016 LM2705

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Inductor Selection - Boost Regulator
        2. 8.2.2.2 Inductor Selection - SEPIC Regulator
        3. 8.2.2.3 Diode Selection
        4. 8.2.2.4 Capacitor Selection
      3. 8.2.3 Application Curves
    3. 8.3 Additional Applications
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)(2)
MIN MAX UNIT
VIN 7.5 V
SW voltage 21 V
FB voltage 2 V
SHDN voltage 7.5 V
Maximum junction temperature, TJ(3) 150 °C
Lead temperature Soldering (10 seconds) 300 °C
Vapor phase (60 seconds) 215 °C
Infrared (15 seconds) 220 °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) The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(MAX), the junction-to-ambient thermal resistance, RθJA, and the ambient temperature, TA. See Thermal Information for the thermal resistance. The maximum allowable power dissipation at any ambient temperature is calculated using: PD(MAX) = (TJ(MAX) − TA) / RθJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature.

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V
Machine model(2) ±200
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) ESD susceptibility using the machine model is 150 V for SW pin.

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNIT
Supply voltage 2.2 7 V
SW voltage, maximum 20.5 V
Junction temperature(1) –40 125 °C
(1) All limits specified at room temperature and at temperature extremes. All room temperature limits are 100% production tested or specified through statistical analysis. All limits at temperature extremes are specified via correlation using standard statistical quality control (SQC) methods. All limits are used to calculate average outgoing quality level (AOQL).

6.4 Thermal Information

THERMAL METRIC(1) LM2705 UNIT
DBV (SOT-23)
5 PINS
RθJA Junction-to-ambient thermal resistance 164.9 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 116.8 °C/W
RθJB Junction-to-board thermal resistance 27.8 °C/W
ψJT Junction-to-top characterization parameter 13.6 °C/W
ψJB Junction-to-board characterization parameter 27.3 °C/W
(1) For more information about traditional and new thermal metrics, see Semiconductor and IC Package Thermal Metrics.

6.5 Electrical Characteristics

Unless otherwise specified, specifications apply for TJ = 25°C and VIN = 2.2 V.
PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX
(1)		 UNIT
IQ Device disabled FB = 1.3 V 40 µA
FB = 1.3 V, –40°C to 125°C 70
Device enabled FB = 1.2 V 235
FB = 1.2 V, –40°C to 125°C 300
Shutdown SHDN = 0 V 0.01 2.5
VFB Feedback trip point 1.237 V
–40°C to 125°C 1.189 1.269
ICL Switch current limit 150 mA
–40°C to 125°C 100 180
IB FB pin bias current FB = 1.23 V(3) 30 nA
FB = 1.23 V, –40°C to 125°C(3) 120
VIN Input voltage –40°C to 125°C 2.2 7 V
RDSON Switch RDSON 0.7 Ω
–40°C to 125°C 1.6
TOFF Switch off time 400 ns
ISD SHDN pin current SHDN = VIN, TJ = 25°C 0 80 nA
SHDN = VIN, TJ = 125°C 15
SHDN = GND 0
IL Switch leakage current VSW = 20 V 0.05 5 µA
UVP Input undervoltage lockout ON/OFF threshold 1.8 V
VFB hysteresis Feedback hysteresis 8 mV
SHDN threshold SHDN low 0.7 V
–40°C to 125°C 0.3
SHDN high 0.7
–40°C to 125°C 1.1
(1) All limits specified at room temperature and at temperature extremes. All room temperature limits are 100% production tested or specified through statistical analysis. All limits at temperature extremes are specified via correlation using standard statistical quality control (SQC) methods. all limits are used to calculate average outgoing quality level (AOQL).
(2) Typical numbers are at 25°C and represent the most likely norm.
(3) Feedback current flows into the pin.

6.6 Typical Characteristics

LM2705 20039705.png
Figure 1. Enable Current vs VIN (Device Switching)
LM2705 20039713.png
Figure 3. SHDN Threshold vs VIN
LM2705 20039715.png
Figure 5. Switch RDSON vs VIN
LM2705 20039727.png
Figure 7. Output Voltage vs Load Current
LM2705 20039728.png
1) Load: 0.5 mA to 5 mA to 0.5 mA, DC VOUT = 20 V
2) VOUT: 200 mV/div, AC VIN = 3 V
3. IL: 100 mA/div, DC T = 100 µs/div
Figure 9. Step Response
LM2705 20039730.png
1. VSW: 20 V/div, DC VIN = 2.7 V VOUT = 20 V
2. Inductor Current: 100 mA/div, DC IOUT = 2.5 mA
3. VOUT, 200 mV/div, AC
Figure 11. Typical Switching Waveform
LM2705 20039706.png
Figure 2. Disable Current vs VIN (Device Not Switching)
LM2705 20039737.png
Figure 4. Switch Current Limit vs VIN
LM2705 20039723.gif
Figure 6. FB Trip Point and FB Pin Current vs Temperature
LM2705 20039741.png
Figure 8. Off Time vs Temperature
LM2705 20039729.png
1) SHDN: 1 V/div, DC VIN = 3 V VOUT = 20 V
2) VOUT: 10 V/div, AC T = 100 µs/div RL = 3.9 kΩ
3. IL: 100 mA/div, DC
Figure 10. Start-Up and Shutdown