SNVS250F November   2004  – February 2016 LM3670

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Connection Diagram
  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
      1. 7.3.1 Circuit Operation
      2. 7.3.2 Soft Start
      3. 7.3.3 LDO - Low Dropout Operation
    4. 7.4 Device Functional Modes
      1. 7.4.1 PWM Operation
        1. 7.4.1.1 Internal Synchronous Rectification
        2. 7.4.1.2 Current Limiting
      2. 7.4.2 PFM Operation
      3. 7.4.3 Shutdown
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Typical Application: Fixed Output
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Inductor Selection
            1. 8.2.1.2.1.1 Method 1
            2. 8.2.1.2.1.2 Method 2
          2. 8.2.1.2.2 Input Capacitor Selection
          3. 8.2.1.2.3 Output Capacitor Selection
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Typical Application: Adjustable Output
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Output Voltage Selection for Adjustable LM3670
        3. 8.2.2.3 Application Curves
  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 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 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 pin: voltage to GND –0.2 6 V
EN pin: voltage to GND –0.2 6 V
FB, SW pins (GND −0.2) VIN + 0.2 V
Junction temperature, TJ-MAX –45 125 °C
Maximum lead temperature  (soldering, 10 seconds) 260 °C
Storage temperature, Tstg –45 150 °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.

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±200
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)(1)
MIN NOM MAX UNIT
Input voltage 2.5 5.5 A
Recommended load current 0 350 mA
Junction temperature, TJ –40 125 °C
Ambient temperature, TA –40 85 °C
(1) All voltages are with respect to the potential at the GND pin.

6.4 Thermal Information

THERMAL METRIC(1) LM3670 UNIT
DBV (SOT-23)
5 PINS
RθJA Junction-to-ambient thermal resistance 163.3 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 114.3 °C/W
RθJB Junction-to-board thermal resistance 26.8 °C/W
ψJT Junction-to-top characterization parameter 12.4 °C/W
ψJB Junction-to-board characterization parameter 26.3 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953.

6.5 Electrical Characteristics

Unless otherwise specified, limits for typical values are TJ = 25°C, and minimum and maximum limits apply over the full operating junction temperature range (−40°C ≤ TJ ≤ +125°C); VIN = 3.6 V, VOUT = 1.8 V, IOUT = 150 mA, EN = VIN.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
VIN Input voltage See(1) 2.5 5.5 V
VOUT Fixed output voltage: 1.2 V 2.5 V ≤ VIN ≤ 5.5 V
IOUT = 10 mA		 –2% 4%
2.5 V ≤ VIN ≤ 5.5 V
0 mA ≤ IOUT ≤ 150 mA		 –4.5% 4%
Fixed output voltage: 1.5 V 2.5 V ≤ VIN ≤ 5.5 V
IOUT = 10 mA		 –2.5% 4%
2.5 V ≤ VIN ≤ 5.5 V
0 mA ≤ IOUT ≤ 350 mA		 –5% 4%
Fixed output voltage: 1.6 V, 1.875 V 2.5 V ≤ VIN ≤ 5.5 V
IOUT = 10 mA		 –2.5% 4%
2.5 V ≤ VIN ≤ 5.5V
0 mA ≤ IOUT ≤ 350 mA		 –5.5% 4%
Fixed output voltage: 1.8 V 2.5 V ≤ VIN ≤ 5.5 V
IOUT = 10 mA		 –1.5% 3%
2.5 V ≤ VIN ≤ 5.5 V
0 mA ≤ IOUT ≤ 350 mA		 –4.5% 3%
Fixed output voltage: 3.3 V 3.6 V ≤ VIN ≤ 5.5 V
IOUT = 10 mA		 –2% 4%
3.6V ≤ VIN ≤ 5.5V
0 mA ≤ IOUT ≤ 350 mA		 –6% 4%
Adjustable output voltage(2) 2.5 V ≤ VIN ≤ 5.5 V
IOUT = 10 mA		 –2.5% 4.5%
2.5 V ≤ VIN ≤ 5.5 V
0 mA ≤ IOUT ≤ 150 mA		 –4% 4.5%
Line_reg Line regulation 2.5 V ≤ VIN ≤ 5.5 V
IOUT = 10 mA		 0.26 %/V
Load_reg Load regulation 150 mA ≤ IOUT ≤ 350 mA 0.0014 %/mA
VREF Internal reference voltage 0.5 V
IQ_SHDN Shutdown supply current TA = 85ºC 0.1 1 µA
IQ DC bias current into VIN No load, device is not switching (VOUT forced higher than programmed output voltage) 15 30 µA
VUVLO Minimum VIN below which VOUT is disabled TA = −40°C ≤ TJ ≤ 125°C 2.4 V
RDSON (P) Pin-pin resistance for PFET VIN = VGS= 3.6V 360 690 mΩ
RDSON (N) Pin-pin resistance for NFET VIN = VGS= 3.6 V 250 660 mΩ
ILKG (P) P channel leakage current VDS = 5.5 V, TA = 25°C 0.1 1 µA
ILKG (N) N channel leakage current VDS = 5.5 V, TA = 25°C 0.1 1.5 µA
ILIM Switch peak current limit 400 620 750 mA
η Efficiency VIN = 3.6 V, VOUT = 1.8 V
ILOAD = 1 mA		 91%
VIN = 3.6 V, VOUT = 1.8 V
ILOAD = 10 mA		 94%
VIN = 3.6 V, VOUT = 1.8 V
ILOAD = 100 mA		 94%
VIN = 3.6 V, VOUT = 1.8 V
ILOAD = 200 mA		 94%
VIN = 3.6 V, VOUT = 1.8 V
ILOAD = 300 mA		 92%
VIN = 3.6 V, VOUT = 1.8 V
ILOAD = 350 mA		 90%
VIH Logic high input 1.3 V
VIL Logic low input 0.4 V
IEN Enable (EN) input current 0.01 1 µA
ƒOSC Internal oscillator frequency PWM mode 550 1000 1300 kHz
(1) The input voltage range recommended for the specified output voltages are given below: VIN = 2.5 V to 5.5 V for 0. 7 V ≤ VOUT < 1.875 V, VIN = ( VOUT + VDROPOUT) to 5.5 for 1.875 ≤ VOUT ≤ 3.3 V, where VDROPOUT = ILOAD × (RDSON (P) + RINDUCTOR).
(2) Output voltage specification for the adjustable version includes tolerance of the external resistor divider.

6.6 Typical Characteristics

Unless otherwise stated, VIN = 3.6 V and VOUT= 1.8 V.
LM3670 20075804.gif
Figure 1. IQ (Non-Switching) vs VIN
LM3670 20075806.gif
Figure 3. VOUT vs VIN
LM3670 20075808.gif
Figure 5. Efficiency vs IOUT
LM3670 20075810.gif
Figure 7. Frequency vs Temperature
LM3670 20075812_nvs250.gif
VIN = 2.6 V to 3.6 V ILOAD = 100 mA
Figure 9. Line Transient
LM3670 20075816.gif
ILOAD = 3 mA to 280 mA
Figure 11. Load Transient
LM3670 20075822.gif
Figure 13. PFM Mode VSW, VOUT, IINDUCTOR vs Time
LM3670 20075824.gif
ILOAD = 350 mA
Figure 15. Soft Start VIN, VOUT, IINDUCTOR vs Time
LM3670 20075805.gif
Figure 2. IQ vs Temperature
LM3670 20075807.gif
Figure 4. VOUT vs IOUT
LM3670 20075809.gif
Figure 6. Efficiency vs VIN
LM3670 20075811.gif
Figure 8. RDSON vs. VIN P and N Channels
LM3670 20075813_nvs250.gif
VIN = 3.6 V to 4.6 V ILOAD = 100 mA
Figure 10. Line Transient
LM3670 20075817.gif
ILOAD = 0 mA to 70 mA
Figure 12. Load Transient
LM3670 20075823.gif
Figure 14. PWM Mode VSW, VOUT, IINDUCTOR vs Time