SNVS087AE October   2000  – May 2015 LP3985

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 Performance Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 No-Load Stability
      2. 7.3.2 On/Off Input Operation
      3. 7.3.3 Fast On-Time
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation with VOUT(TARGET) + 0.3 V ≤ VIN ≤ 6 V
      2. 7.4.2 Operation Using the EN Pin
  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 External Capacitors
        2. 8.2.2.2 Input Capacitor
        3. 8.2.2.3 Output Capacitor
        4. 8.2.2.4 Capacitor Characteristics
        5. 8.2.2.5 Noise Bypass Capacitor
        6. 8.2.2.6 Thermal Considerations
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
    3. 10.3 DSBGA Mounting
    4. 10.4 DSBGA Light Sensitivity
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 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)(3)
MIN MAX UNIT
IN, EN –0.3 6.5 V
OUT −0.3 (VIN + 0.3) < 6.5
Junction temperature 150 °C
Lead temperature 235
Pad temperature(4) 235
Maximum power dissipation SOT-23(5) 364 mW
DSBGA(5) 314
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) All voltages are with respect to potential at the GND pin.
(3) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and specifications.
(4) Additional information on lead temperature and pad temperature can be found in Texas Instruments Application Note AN-1187 Leadless Leadframe Package (LLP) (SNOA401).
(5) The Absolute Maximum power dissipation depends on the ambient temperature and can be calculated using the formula: PD = (TJ - TA)/RθJA,where TJ is the junction temperature, TA is the ambient temperature, and RθJA is the junction-to-ambient thermal resistance. The 364-mW rating for SOT23-5 appearing under Absolute Maximum Ratings results from substituting the Absolute Maximum junction temperature, 150°C for TJ, 70°C for TA, and 220°C/W for RθJA. More power can be dissipated safely at ambient temperatures below 70°C . Less power can be dissipated safely at ambient temperatures above 70°C. The Absolute Maximum power dissipation can be increased by 4.5 mW for each degree below 70°C, and it must be derated by 4.5 mW for each degree above 70°C.

6.2 ESD Ratings

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

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN MAX UNIT
VIN Supply input voltage 2.5(1) 6 V
VEN ON/OFF input voltage 0 VIN V
IOUT Output current 150 mA
TJ Operating junction temperature −40 125 °C
(1) Recommended minimum VIN is the greater of 2.5-V or VOUT(MAX) + rated dropout voltage (max) for operating load current.

6.4 Thermal Information

THERMAL METRIC(1) LP3985 UNIT
SOT-23 (DBV) DSBGA (YZR)
5 PINS
RθJA Junction-to-ambient thermal resistance 220 255 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 79.8 0.8
RθJB Junction-to-board thermal resistance 31.6 107.9
ψJT Junction-to-top characterization parameter 3.1 0.5
ψJB Junction-to-board characterization parameter 31.1 107.9
RθJC(bot) Junction-to-case (bottom) thermal resistance N/A N/A
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

6.5 Electrical Characteristics

Unless otherwise specified: VIN = VOUT(nom) + 0.5 V, CIN = 1 μF, IOUT = 1 mA, COUT = 1 μF, CBYPASS = 0.01 μF. Minimum (MIN) and Maximum (MAX) values apply over –40°C ≤ TJ ≤ 125°C and typical values are TA = 25°C, unless otherwise indicated. (1)(2)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
ΔVOUT Output voltage tolerance IOUT = 1 mA –2(3)
–3		 2(3)
3		 % of VOUT(nom)
Line regulation error VIN = (VOUT(nom) + 0.5 V) to 6 V,
For 4.7-V to 5-V options
For all other options		  
–0.19
–0.1		  
0.19
0.1		 %/V
Load regulation error(4) IOUT = 1 mA to 150 mA
LP3985IM5 (SOT23-5)		 0.0025 0.005 %/mA
LP3985 (DSBGA) 0.0004 0.002 %/mA
Output AC line regulation VIN = VOUT(nom) + 1 V,
IOUT = 150 mA (Figure 1)		 1.5 mVP-P
PSRR Power supply rejection ratio VIN = VOUT(nom) + 0.2 V,
f = 1 kHz,
IOUT = 50 mA (Figure 2)		 50 dB
VIN = VOUT(nom) + 0.2 V,
ƒ = 10 kHz,
IOUT = 50 mA (Figure 2)		 40 dB
IQ Quiescent current VEN = 1.4 V, IOUT = 0 mA
For 4.7-V to 5-V options
For all other options		  
100
85		  
165
150		 µA
VEN = 1.4 V, IOUT = 0 to 150 mA
For 4.7-V to 5-V options
For all other options		  
155
140		  
250
200
VEN = 0.4 V 0.003 1.5
Dropout voltage(5) IOUT = 1 mA 0.4 2 mV
IOUT = 50 mA 20 35 mV
IOUT = 100 mA 45 70 mV
IOUT = 150 mA 60 100 mV
ISC Short circuit current limit Output Grounded
(Steady State)		 600 mA
IOUT(PK) Peak output current VOUT ≥ VOUT(nom) – 5% 300 550 mA
TON Turnon time(6) CBYPASS = 0.01 µF 200 µs
en Output noise voltage(7) BW = 10 Hz to 100 kHz,
COUT = 1 µF		 30 µVRMS
Output noise density CBP = 0 230 nV/ √Hz
IEN Maximum input current at EN VEN = 0.4 V and VIN = 6 V ±1 nA
VIL Maximum low-level input voltage at EN VIN = 2.5 V to 6 V 0.4 V
VIH Minimum high-level input voltage at EN VIN = 2.5 V to 6 V 1.4 V
TSD Thermal shutdown temperature 160 °C
Thermal shutdown hysteresis 20 °C
(1) All limits are verified. All electrical characteristics having room-temperature limits are tested during production with TA = 25°C or correlated using Statistical Quality Control (SQC) methods. All hot and cold limits are specified by correlating the electrical characteristics to process and temperature variations and applying statistical process control.
(2) The target output voltage, which is labeled VOUT(NOM), is the desired voltage option.
(3) TA = 25°C only.
(4) An increase in the load current results in a slight decrease in the output voltage and vice versa.
(5) Dropout voltage is the input-to-output voltage difference at which the output voltage is 100mV below its nominal value. This specification does not apply for input voltages below 2.5V.
(6) Turnon time is time measured between the enable input just exceeding VIH and the output voltage just reaching 95% of its nominal value.
(7) The output noise varies with output voltage option. The 30 µVRMS is measured with 2.5-V voltage option. To calculate an approximated output noise for other options, use the equation: (30µVRMS)(X)/2.5, where X is the voltage option value.
LP3985 10136408.pngFigure 1. Line Transient Input Test Signal
LP3985 10136409.pngFigure 2. PSRR Input Test Signal

6.6 Typical Performance Characteristics

Unless otherwise specified, CIN = COUT = 1 µF ceramic, CBYPASS = 0.01 µF, VIN = VOUT + 0.2 V, TA = 25°C, EN pin is tied to VIN.
LP3985 10136441.gif
Figure 3. Output Voltage Change vs Temperature
LP3985 10136440.png
Figure 5. Ground Current vs Load Current
LP3985 10136437.png
Figure 7. Ground Current vs VIN at −40°C
LP3985 10136445.png
Figure 9. Short Circuit Current (DSBGA)
LP3985 10136447.png
Figure 11. Short Circuit Current (SOT)
LP3985 10136449.png
Figure 13. Short Circuit Current (SOT)
LP3985 10136451.png
Figure 15. Short Circuit Current (DSBGA)
LP3985 10136410.png
Figure 17. Output Noise Spectral Density
LP3985 10136412.png
VIN = VOUT + 1 V
Figure 19. Ripple Rejection
LP3985 10136414.png
VIN = VOUT + 0.2 V
Figure 21. Start-up Time
LP3985 10136417.png
VIN = 4.2 V
Figure 23. Start-up Time
LP3985 10136419.png
VIN = 4.2 V
Figure 25. Start-up Time
LP3985 10136421.png
Figure 27. Line Transient Response
LP3985 10136422.png
VIN = 4.2 V
Figure 29. Load Transient Response
LP3985 10136425.png
VIN = 4.2 V
Figure 31. Load Transient Response
LP3985 10136455.png
VIN = VOUT + 0.2 V
Figure 33. Enable Response
LP3985 10136465.png
VIN = 4.2 V
Figure 35. Output Impedance

LP3985 10136433.png
Figure 4. Dropout Voltage vs Load Current
LP3985 10136435.png
Figure 6. Ground Current vs VIN at 25°C
LP3985 10136439.png
Figure 8. Ground Current vs VIN at 125°C
LP3985 10136446.png
Figure 10. Short Circuit Current (DSBGA)
LP3985 10136448.png
Figure 12. Short Circuit Current (SOT)
LP3985 10136450.png
Figure 14. Short Circuit Current (SOT)
LP3985 10136452.png
Figure 16. Short Circuit Current (DSBGA)
LP3985 10136411.png
VIN = VOUT + 0.2 V
Figure 18. Ripple Rejection
LP3985 10136413.png
VIN = 5 V
Figure 20. Ripple Rejection
LP3985 10136416.png
VIN = VOUT + 0.2 V
Figure 22. Start-up Time
LP3985 10136418.png
VIN = VOUT + 0.2 V
Figure 24. Start-up Time
LP3985 10136420.png
Figure 26. Line Transient Response
LP3985 10136423.png
VIN = 3.2 V
Figure 28. Load Transient Response
LP3985 10136424.png
VIN = 3.2 V
Figure 30. Load Transient Response
LP3985 10136453.png
VIN = VOUT + 0.2 V
Figure 32. Enable Response
LP3985 10136456.png
VIN = 4.2 V
Figure 34. Enable Response
LP3985 10136466.png
VIN = VOUT + 0.2 V
Figure 36. Output Impedance