SNVS225H February   2003  – June 2015 LP3871 , LP3874

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 Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 Shutdown (SD)
      2. 7.3.2 Short-Circuit Protection
      3. 7.3.3 Low Dropout Voltage
      4. 7.3.4 SENSE Pin
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Active Mode
      3. 7.4.3 ERROR Flag Operation
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Reverse Current Path
      2. 8.1.2 Turnon Characteristics for Output Voltages Programmed To 2 V or Below
    2. 8.2 Typical Applications
      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 Selecting a Capacitor
        3. 8.2.2.3 Capacitor Characteristics
          1. 8.2.2.3.1 Ceramic
          2. 8.2.2.3.2 Tantalum
          3. 8.2.2.3.3 Aluminum
        4. 8.2.2.4 RFI/EMI Susceptibility
        5. 8.2.2.5 Output Noise
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Power Dissipation
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Related Links
    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

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6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)(2)
MIN MAX UNIT
Input supply voltage (survival) −0.3 7.5 V
Shutdown input voltage (survival) −0.3 7.5 V
Output voltage (survival)(3)(4) −0.3 6 V
IOUT (survival) Short-circuit protected
Maximum voltage for ERROR Pin VIN V
Maximum voltage for SENSE Pin VOUT V
Power dissipation(5) 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) If Military/Aerospace specified devices are required, please contact the TI Sales Office/Distributors for availability and specifications.
(3) If used in a dual-supply system where the regulator load is returned to a negative supply, the output must be diode-clamped to ground.
(4) The output PMOS structure contains a diode between the IN and OUT pins. This diode is normally reverse biased. This diode will get forward biased if the voltage at the output terminal is forced to be higher than the voltage at the input terminal. This diode can typically withstand 200 mA of DC current and 1 A of peak current.
(5) Internal thermal shutdown circuitry protects the device from permanent damage.

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) ±500
(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)
MIN MAX UNIT
Input supply voltage(1) 2.5 7 V
Shutdown input voltage −0.3 7 V
Maximum operating current (DC) 0.8 A
Junction temperature −40 125 °C
(1) The minimum operating value for VIN is equal to either [VOUT(NOM) + VDROPOUT] or 2.5 V, whichever is greater.

6.4 Thermal Information

THERMAL METRIC(1) LP3871, LP3874 UNIT
NC (SOT-223) KTT (DDPAK/TO-263)
5 PINS 5 PINS
RθJA Junction-to-ambient thermal resistance 65.2 40.3 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 47.2 43.4 °C/W
RθJB Junction-to-board thermal resistance 9.9 23.1 °C/W
ψJT Junction-to-top characterization parameter 3.4 11.5 °C/W
ψJB Junction-to-board characterization parameter 9.7 22 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance — 1 °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: TJ = 25°C, VIN = VO(NOM) + 1 V, IL = 10 mA, COUT = 10 µF, VSD = 2 V.
PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX(1) UNIT
VOUT Output voltage tolerance(3) VOUT + 1 V ≤ VIN ≤ 7 V, 10 mA ≤ IL ≤ 0.8 A –1.5% 0% 1.5%
VOUT + 1 V ≤ VIN ≤ 7 V, 10 mA ≤ IL ≤ 0.8 A, –40°C ≤ TJ ≤ 125°C –3% 3%
ΔVOL Output voltage line regulation(3) VOUT + 1 V ≤ VIN ≤ 7 V 0.02%
VOUT + 1 V ≤ VIN ≤ 7 V, –40°C ≤ TJ ≤ 125°C 0.06%
ΔVO/ ΔIOUT Output voltage load regulation(3) 10 mA ≤ IL ≤ 0.8 A 0.04%
10 mA ≤ IL ≤ 0.8 A, –40°C ≤ TJ ≤ 125°C 0.1%
VIN – VOUT Dropout voltage(4) IL = 80 mA 24 35 mV
IL = 80 mA, –40°C ≤ TJ ≤ 125°C 40
IL = 0.8 A 240 300
IL = 0.8 A, –40°C ≤ TJ ≤ 125°C 350
IGND Ground pin current in normal operation mode IL = 150 mA 5 9 mA
IL = 150 mA, –40°C ≤ TJ ≤ 125°C 10
IL = 0.8 A 6 14
IL = 0.8 A, –40°C ≤ TJ ≤ 125°C 15
IGND Ground pin current in shutdown mode VSD ≤ 0.3 V 0.01 10 µA
–40°C ≤ TJ ≤ 85°C 50
IO(PK) Peak output current VOUT ≥ VO(NOM) – 4% 1 A
SHORT CIRCUIT PROTECTION
ISC Short-circuit current 2.3 A
SHUTDOWN INPUT
VSDT Shutdown threshold Output = High VIN V
Output = High, –40°C ≤ TJ ≤ 125°C 2
Output = Low 0
Output = Low, –40°C ≤ TJ ≤ 125°C 0.3
TdOFF Turnoff delay IL = 0.8 A 20 µs
TdON Turnon delay IL = 0.8 A 25 µs
ISD SD input current VSD = VIN 1 nA
ERROR FLAG
VT Threshold See(5) 10%
See(5), –40°C ≤ TJ ≤ 125°C 5% 16%
VTH Threshold hysteresis See(5) 5%
See(5), –40°C ≤ TJ ≤ 125°C 2% 8%
VEF(Sat) ERROR flag saturation Isink = 100 µA 0.02 V
Isink = 100 µA, –40°C ≤ TJ ≤ 125°C 0.1
Td Flag reset delay 1 µs
Ilk ERROR flag pin leakage current 1 nA
Imax ERROR flag pin sink current VError = 0.5 V 1 mA
AC PARAMETERS
PSRR Ripple rejection VIN = VOUT + 1 V, COUT = 10 µF
VOUT = 3.3 V, ƒ = 120 Hz		 73 dB
VIN = VOUT + 0.5 V, COUT = 10 µF
VOUT = 3.3 V, ƒ = 120 Hz		 57
ρn(l/f) Output noise density ƒ = 120 Hz 0.8 µV
en Output noise voltage BW = 10 Hz – 100 kHz, VOUT = 2.5 V 150 µVRMS
BW = 300 Hz – 300 kH, VOUT = 2.5 V 100
(1) Limits are specified by testing, design, or statistical correlation.
(2) Typical numbers are at 25°C and represent the most likely parametric norm.
(3) Output voltage line regulation is defined as the change in output voltage from the nominal value due to change in the input line voltage. Output voltage load regulation is defined as the change in output voltage from the nominal value due to change in load current. The line and load regulation specification contains only the typical number. However, the limits for line and load regulation are included in the output voltage tolerance specification.
(4) Dropout voltage is defined as the minimum input to output differential voltage at which the output drops 2% below the nominal value. Dropout voltage specification applies only to output voltages of 2.5 V and above. For output voltages below 2.5 V, the dropout voltage is nothing but the input to output differential, because the minimum input voltage is 2.5 V.
(5) ERROR Flag threshold and hysteresis are specified as percentage of regulated output voltage. See ERROR Flag Operation.

6.6 Typical Characteristics

Unless otherwise specified: TJ = 25°C, COUT = 10 µF, CIN = 10 µF, SD pin is tied to VIN, VOUT = 2.5 V, VIN = VO(NOM) + 1 V,
IL = 10 mA.
LP3871 LP3874 20063160.gif
Figure 1. Dropout Voltage vs Output Load Current
LP3871 LP3874 20063155.gif
Figure 3. Shutdown IQ vs Junction Temperature
LP3871 LP3874 20063158.gif
Figure 5. DC Load Regulation vs Junction Temperature
LP3871 LP3874 20063154.gif
IL = 800 mA
Figure 2. Ground Current vs Output Voltage
LP3871 LP3874 20063157.gif
Figure 4. ERROR Flag Threshold vs Junction Temperature
LP3871 LP3874 20063159.gif
Figure 6. DC Line Regulation vs Temperature