SNOSCT6F March   2013  – January 2017 LP38798

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
      1. 7.3.1 Noise Filter
      2. 7.3.2 Enable Input Operation
      3. 7.3.3 Undervoltage Lockout (UVLO)
      4. 7.3.4 Output Current Limiting
      5. 7.3.5 Thermal Shutdown
    4. 7.4 Device Functional Modes
    5. 7.5 Programming
      1. 7.5.1 Programming the Output Voltage
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application: VOUT = 5 V
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Input Capacitor Recommendations
        3. 8.2.2.3 Output Capacitor Recommendations
        4. 8.2.2.4 Charge Pump
        5. 8.2.2.5 Setting the Output Voltage
        6. 8.2.2.6 Device Dissipation
      3. 8.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
    4. 10.4 Estimating the Junction Temperature
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Suppport
        1. 11.1.1.1 Custom Design With WEBENCH® Tools
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 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)
MIN MAX UNIT
VIN, VIN(CP) –0.3 22 V
VOUT, VOUT(FB) –0.3 VIN + 0.3 V
VSET –0.3 VIN + 0.3 V
VFB –0.3 VIN + 0.3 V
VEN –0.3 6 V
Power dissipation(2) Internally Limited
IOUT (Survival) Internally Limited
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) The value of RθJA for the WSON package is dependent on PCB copper area, copper thickness, the number of copper layers in the PCB, and the number of thermal vias under the exposed thermal pad (DAP). Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator may go into thermal shutdown. See Thermal Considerations.

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) ±250
(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

MIN MAX UNIT
Input voltage, VIN 3 20 V
Output voltage, VOUT 1.2 (VIN – VDO) V
Enable voltage, VEN 0 5 V
Junction temperature, TJ –40 125 °C

6.4 Thermal Information

THERMAL METRIC(1) LP38798 UNIT
DNT (WSON)
12 PINS
RθJA Junction-to-ambient thermal resistance 35.4 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 29.4 °C/W
RθJB Junction-to-board thermal resistance 12.6 °C/W
ψJT Junction-to-top characterization parameter 0.2 °C/W
ψJB Junction-to-board characterization parameter 12.8 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance 2.6 °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 stated the following conditions apply: VIN = 5.5 V, VSET = 5 V, CCP = 10 nF X7R, CIN = 10 μF, 50-mΩ tantalum, COUT = 10 μF X7R MLCC, IOUT = 10 mA, and TJ = –40°C to +125°C.
PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX(1) UNIT
VFB Feedback voltage VIN = 5.5 V
TJ = 25°C		 1.188 1.2 1.212 V
5.5 V ≤ VIN ≤ 20 V 1.176 1.2 1.224
VOS VOUT – VSET 0 3.5 16 mV
IFB Feedback pin current VFB = 1.2 V 0 1 µA
ISET SET pin internal current sink VIN = 3 V, VSET = 2.5 V 46 μA
VIN = 5.5 V, VSET = 5 V 25.2 52 67.8
VIN = 12.5 V, VSET = 12 V 71
ΔVOUT / ΔVIN Line regulation(3) 5.5 V ≤ VIN ≤ 20 V
IOUT = 10 mA		 0.005 %/V
ΔVOUT / ΔIOUT Load regulation(4) VIN = 5.5 V
10 mA ≤ IOUT ≤ 800 mA		 –0.2 %/A
VDO Dropout voltage(5) IOUT = 800 mA 200 420 mV
UVLO Undervoltage lock-out VIN Rising until output is On 2.47 2.65 2.83 V
ΔUVLO UVLO hysteresis VIN Falling from > UVLO threshold until output is Off 180 mV
IGND Ground pin current(6) IOUT = 800 mA 1.4 2.25 mA
VIN = 20 V, IOUT = 800 mA 1.6 2.51
IQ Ground pin current, quiescent(6) IOUT = 0 mA 1.4 2.1 mA
VIN = 20 V, IOUT = 0 mA 1.5 2.2
ISD Ground pin current, shutdown(6) VEN = 0 V 9 20 µA
VIN = 20 V, VEN = 0 V 12 40
ISC Short-circuit current RLOAD = 0 Ω 850 1200 1600 mA
ΔVCP VCP – VIN 2.8 V
VIN = 20 V 2.3
tSTART Start-up time From VEN > VEN(ON) to VOUT ≥ 98% of VOUT(NOM) 155 300 µs
PSRR Power Supply Rejection Ratio VOUT = 1.2 V, f = 10 kHz 110 dB
VOUT = 5 V, f = 10 kHz 90
VOUT = 1.2 V, f = 100 kHz 90
VOUT = 5 V, f = 100 kHz 60
VOUT = 1.2 V, f = 1 MHz 70
VOUT = 5 V, f = 1 MHz 60
eN Output noise voltage (RMS) VIN = 3 V, VOUT = 1.2 V
COUT = 1 µF X7R
BW = 10 Hz to 100 kHz		 4.96 µV(RMS)
VIN = 3 V, VOUT = 1.2 V
BW = 10 Hz to 100 kHz		 5.21
VIN = 3 V, VOUT = 1.2 V
BW = 10 Hz to 10 MHz		 11.53
VIN = 6 V, VOUT = 5 V
COUT = 1 µF X7R
BW = 10 Hz to 100 kHz		 5.38
VIN = 6 V, VOUT = 5 V
BW = 10 Hz to 100 kHz		 5.43
VIN = 6 V, VOUT = 5 V
BW = 10 Hz to 10 MHz		 11.58
ENABLE INPUT
VEN(ON) Enable ON threshold voltage VEN rising from 500 mV until Output is ON 1.14 1.24 1.34 V
ΔVEN Enable threshold voltage hysteresis VEN falling from VEN(ON) 110 mV
IEN(IL) EN pin pullup current VEN = 500 mV 2 3 µA
IEN(IH) EN pin pullup current VEN = 2 V 2 3
VEN(CLAMP) Enable pin clamp voltage EN pin = Open 5 V
THERMAL SHUTDOWN
TSD Thermal shutdown Junction temperature (TJ) rising 170 °C
ΔTSD Thermal shutdown hysteresis Junction temperature (TJ) falling from TSD 12
(1) Minimum and maximum limits are ensured through test, design, or statistical correlation over the operating junction temperature (TJ ) range of –40°C to 125°C, unless otherwise stated.
(2) Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only.
(3) Line Regulation: % change in VOUT(NOM) for every 1V change in VIN= (( ΔVOUT / VOUT(NOM)) / ΔVIN ) × 100%
(4) Load Regulation: % change in VOUT(NOM) for every 1A change in IOUT = (( ΔVOUT / VOUT(NOM) ) / ΔIOUT ) × 100%
(5) Dropout voltage (VDO) is defined as the differential voltage measured between VOUT and VIN when VIN, falling from VIN = VOUT + 1 V, causes VOUT to drop 2% below the value measured with VIN = VOUT + 1 V. Dropout voltage specification does not apply when the programmed output voltage is below the Minimum Operating Input Voltage.
(6) Ground pin current is the sum of the current in both GND pins (pin 4 and pin 5) only, and does not include current from the SET pin.

6.6 Typical Characteristics

Unless otherwise specified: VIN = 5.5 V, VOUT = 5 V, IOUT = 10 mA, COUT = 10 µF MLCC 16 V X7R, and TJ = 25°C.
LP38798 C007_SNOSCT6.png
Figure 1. PSRR
LP38798 C009_SNOSCT6.png
Figure 3. Noise Density
LP38798 C001_SNOSCT6.png
Figure 5. PSRR
LP38798 C003_SNOSCT6.png
Figure 7. PSRR
LP38798 C005_SNOSCT6.png
Figure 9. PSRR
LP38798 C023_SNOSCT6.png
Figure 11. UVLO Thresholds vs TJ
LP38798 C025_SNOSCT6.png
Figure 13. Enable Thresholds vs VIN
LP38798 C027_SNOSCT6.png
Figure 15. Start-Up Time
LP38798 C038_SNOSCT6.png
Figure 17. VOUT vs Rising VIN
LP38798 C030_SNOSCT6.png
Figure 19. IN Pin Current vs VIN
LP38798 C032_SNOSCT6.png
Figure 21. Enable Pin Pull-Up Current vs VIN
LP38798 C034_SNOSCT6.png
Figure 23. Dropout Voltage vs Output Current
LP38798 C036_SNOSCT6.png
Figure 25. Load Regulation vs TJ
LP38798 C039_SNOSCT6.png
Figure 27. Current Limit, ISC vs TJ
LP38798 C021_SNOSCT6.png
Figure 29. Line Transient
LP38798 C019_SNOSCT6.png
Figure 31. Line Transient
LP38798 C017_SNSOCT6.png
Figure 33. Line Transient
LP38798 C015_SNSOCT6.png
Figure 35. Load Transient
LP38798 C013_SNSOCT6.png
Figure 37. Load Transient
LP38798 C011_SNSOCT6.png
Figure 39. Load Transient
LP38798 C008_SNOSCT6.png
Figure 2. PSRR
LP38798 C010_SNOSCT6.png
Figure 4. Noise Density
LP38798 C002_SNOSCT6.png
Figure 6. PSRR
LP38798 C004_SNOSCT6.png
Figure 8. PSRR
LP38798 C006_SNOSCT6.png
Figure 10. PSRR
LP38798 C024_SNOSCT6.png
Figure 12. Enable Thresholds vs TJ
LP38798 C026_SNOSCT6.png
Figure 14. Start-Up Time
LP38798 C028_SNOSCT6.png
Figure 16. Start-Up Time
LP38798 C029_SNOSCT6.png
Figure 18. VFB Variation vs TJ
LP38798 C031_SNOSCT6.png
Figure 20. VEN(CLAMP) vs VIN
LP38798 C033_SNOSCT6.png
Figure 22. Dropout Voltage vs Output Current
LP38798 C035_SNOSCT6.png
Figure 24. VOUT Variation vs TJ
LP38798 C037_SNOSCT6.png
Figure 26. Line Regulation vs TJ
LP38798 C022_SNOSCT6.png
Figure 28. Line Transient
LP38798 C020_SNOSCT6.png
Figure 30. Line Transient
LP38798 C018_SNOSCT6.png
Figure 32. Line Transient
LP38798 C016_SNSOCT6.png
Figure 34. Load Transient
LP38798 C014_SNSOCT6.png
Figure 36. Load Transient
LP38798 C012_SNSOCT6.png
Figure 38. Load Transient