SNVS482F January   2007  – December 2015

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 Timing Requirements
    7. 6.7 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 Undervoltage Lockout (UVLO)
      2. 7.3.2 Supply Sequencing
      3. 7.3.3 Reverse Voltage
      4. 7.3.4 Soft-Start
      5. 7.3.5 Setting The Output Voltage
      6. 7.3.6 Enable (EN)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Input Voltage
      2. 7.4.2 Bias Voltage
      3. 7.4.3 Enable (EN) Operation
  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
          1. 8.2.2.1.1 Input Capacitor
          2. 8.2.2.1.2 Output Capacitor
          3. 8.2.2.1.3 Bias Capacitor
          4. 8.2.2.1.4 Setting the Output Voltage
          5. 8.2.2.1.5 Feed Forward Capacitor, CFF
        2. 8.2.2.2 Power Dissipation and Heat Sinking
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    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 supply voltage (survival) −0.3 6 V
VBIAS supply voltage (survival) −0.3 6 V
VSS soft-start voltage (survival) −0.3 6 V
VOUT voltage (survival) −0.3 6 V
IOUT current (survival) Internally Limited
Junction temperature −40 150 °C
Power dissipation(3) 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, contact the TI Sales Office/ Distributors for availability and specifications.
(3) Device power dissipation must be de-rated based on device power dissipation (PD), ambient temperature (TA), and package junction to ambient thermal resistance (RθJA). Additional heat-sinking may be required to ensure that the device junction temperature (TJ) does not exceed the maximum operating rating. See the Application and Implementation section for details.

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 NOM MAX UNIT
VIN supply voltage (survival) (VOUT + VDO) to VBIAS V
VBIAS supply voltage (survival)(1) 0.8 V ≤ VOUT ≤ 1.2 V 3 5.5 V
1.2 V < VOUT ≤ 1.8 V 4.5 5.5 V
VEN voltage 0 VBIAS V
IOUT 0 3 mA
Junction temperature(2) −40 125 °C
(1) VIN cannot exceed either VBIAS or 4.5 V, whichever value is lower.
(2) Device power dissipation must be de-rated based on device power dissipation (PD), ambient temperature (TA), and package junction-to-ambient thermal resistance (RθJA). Additional heat sinking may be required to ensure that the device junction temperature (TJ) does not exceed the maximum operating rating. See the Application and Implementation section for details.

6.4 Thermal Information

THERMAL METRIC(1) LP38852-ADJ UNIT
KTW (DDPAK/TO-263) NDZ (TO-220) DDA (SO PowerPAD)
7 PINS 7 PINS 8 PINS
RθJA Junction-to-ambient thermal resistance 34.3 34.0 48.4 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 37.6 36.4 54.6 °C/W
RθJB Junction-to-board thermal resistance 25.3 25.0 29.1 °C/W
ψJT Junction-to-top characterization parameter 6.6 6.3 9.6 °C/W
ψJB Junction-to-board characterization parameter 24.0 23.6 29.0 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance n/a n/a 4.3 °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: VOUT = 0.8 V, VIN = VOUT(NOM) + 1 V, VBIAS = 3 V, VEN = VBIAS, IOUT = 10 mA, CIN = COUT = 10 µF, CBIAS = 1 µF, CSS = open; typical (TYP) limits are for TJ = 25°C only, and minimum (MIN) and maximum (MAX) limits apply over the junction temperature (TJ) range of –40°C to +125°C. Minimum and maximum limits are specified through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
VADJ VADJ accuracy VOUT(NOM)+1 V ≤ VIN ≤ VBIAS ≤ 4.5 V(1)
3 V ≤ VBIAS ≤ 5.5 V, 10 mA ≤ IOUT ≤ 1.5 A
TJ = 25°C		 492.5 500. 507.5 mV
VOUT(NOM)+1 V ≤ VIN ≤ VBIAS ≤ 4.5 V(1)
3 V ≤ VBIAS ≤ 5.5 V, 10 mA ≤ IOUT ≤ 1.5 A		 485 515
VOUT(NOM)+1 V ≤ VIN ≤ VBIAS ≤ 4.5 V(1)
3 V ≤ VBIAS ≤ 5.5 V,
10 mA ≤ IOUT ≤ 1.5 A,
0°C ≤ TJ ≤ +125°C		 490 500. 510
VOUT VOUT range 3 V ≤ VBIAS ≤ 5.5 V 0.8 1.2 V
4.5 V ≤ VBIAS ≤ 5.5 V 0.8 1.8
ΔVOUT/ΔVIN Line regulation, VIN(2) VOUT(NOM)+1 V ≤ VIN ≤ VBIAS 0.04 %/V
ΔVOUT/ΔVBIAS Line regulation, VBIAS(2) 3 V ≤ VBIAS ≤ 5.5 V 0.1 %/V
ΔVOUT/ΔIOUT Output voltage load regulation(3) 10 mA ≤ IOUT ≤ 1.5 A 0.2 %/A
VDO Dropout voltage(4) IOUT = 1.5 A, TJ = 25°C 130 165 mV
IOUT = 1.5 A 180
IGND(IN) Quiescent current drawn from VIN supply VOUT = 0.8 V, VBIAS = 3 V
10 mA ≤ IOUT ≤ 1.5 A
TJ = 25°C		 7 8.5 mA
VOUT = 0.8 V, VBIAS = 3 V
10 mA ≤ IOUT ≤ 1.5 A		 9
VEN ≤ 0.5 V, TJ = 25°C 1 100 μA
VEN ≤ 0.5 V 300
IGND(BIAS) Quiescent current drawn from VBIAS supply 10 mA ≤ IOUT ≤ 1.5 A, TJ = 25°C 3 3.8 mA
10 mA ≤ IOUT ≤ 1.5 A 4.5
VEN ≤ 0.5 V, TJ = 25°C 100 170 μA
VEN ≤ 0.5 V 200
UVLO Undervoltage lockout threshold VBIAS rising until device is functional
TJ = 25°C		 2.2 2.45 2.7 V
VBIAS rising until device is functional 2 2.9
UVLO(HYS) Undervoltage lockout hysteresis VBIAS falling from UVLO threshold until device is non-functional
TJ = 25°C		 60 150 300 mV
VBIAS falling from UVLO threshold until device is non-functional 50 350
ISC Output short-circuit current VIN = VOUT(NOM) + 1 V, VBIAS = 3 V,
VOUT = 0 V		 4.5 A
SOFT-START
rSS Soft-start internal resistance 11 13.5 16 kΩ
tSS Soft-start time
tSS = CSS × rSS × 5		 CSS = 10 nF 675 μs
ENABLE
IEN ENABLE pin current VEN = VBIAS 0.01 μA
VEN = 0 V, VBIAS = 5.5 V, TJ = 25°C –19 –30 –40
VEN = 0 V, VBIAS = 5.5 V –13 –51
VEN(ON) Enable voltage threshold VEN rising until output = ON, TJ = 25°C 1 1.25 1.5 V
VEN rising until output = ON 0.9 1.55
VEN(HYS) Enable voltage hysteresis VEN falling from VEN(ON) until Output = OFF
TJ = 25°C		 50 100 150 mV
VEN falling from VEN(ON) until Output = OFF 30 200
AC PARAMETERS
PSRR (VIN) Ripple rejection for VIN input voltage VIN = VOUT(NOM) + 1 V,
ƒ = 120 Hz		 80 dB
VIN = VOUT(NOM) + 1 V,
ƒ = 1 kHz		 65
PSRR (VBIAS) Ripple rejection for VBIAS voltage VBIAS = VOUT(NOM) + 3 V,
ƒ= 120 Hz		 58 dB
VBIAS = VOUT(NOM) + 3 V,
ƒ = 1 kHz		 58
en Output noise density ƒ = 120 Hz 1 µV/√Hz
Output noise voltage BW = 10 Hz − 100 kHz 150 µVRMS
BW = 300 Hz − 300 kHz 90
THERMAL PARAMETERS
TSD Thermal shutdown junction temperature 160 °C
TSD(HYS) Thermal shutdown hysteresis 10 °C
(1) VIN cannot exceed either VBIAS or 4.5 V, whichever value is lower.
(2) Output voltage line regulation is defined as the change in output voltage from nominal value resulting from a change in input voltage.
(3) Output voltage load regulation is defined as the change in output voltage from nominal value as the load current increases from no load to full load.
(4) Dropout voltage is defined as the input to output voltage differential (VIN – VOUT) where the input voltage is low enough to cause the output voltage to drop 2% from the nominal value.

6.6 Timing Requirements

MIN NOM MAX UNIT
tOFF Turnoff delay time, RLOAD x COUT << tOFF 20 µs
tON Turnon delay time, RLOAD x COUT << tON 15 µs

6.7 Typical Characteristics

Refer to the Typical Application Circuit. Unless otherwise specified: TJ = 25°C, R1 = 1.4 kΩ, R2 = 1 kΩ, CFF= 0.01 µF,
VIN = VOUT(NOM) + 1 V, VBIAS = 3 V, IOUT = 10 mA, CIN = 10-µF ceramic, COUT = 10-µF ceramic, CBIAS = 1-µF Ceramic, CSS = open.
LP38852-ADJ 20213987.png
Figure 1. VBIAS Ground Pin Current (IGND(BIAS)) vs VBIAS
LP38852-ADJ 20213962.png
Figure 3. VIN Ground Pin Current vs Temperature
LP38852-ADJ 20213965.png
Figure 5. Dropout Voltage (VDO) vs Temperature
LP38852-ADJ 20213967.png
Figure 7. VOUT vs Temperature
LP38852-ADJ 20213968.png
Figure 9. UVLO Thresholds vs Temperature
LP38852-ADJ 20213976.png
10 nF To 47 nF
Figure 11. VOUT vs CSS
LP38852-ADJ 20213989.png
Figure 13. Enable Pulldown Current (IEN) vs Temperature
LP38852-ADJ 20213977.png
Figure 15. VIN Line Transient Response
LP38852-ADJ 20213979.png
Figure 17. VBIAS Line Transient Response
LP38852-ADJ 20213970.png
Figure 19. VBIAS PSRR
LP38852-ADJ 20213969.png
Figure 21. Output Noise
LP38852-ADJ 20213961.png
Figure 2. VBIAS Ground Pin Current (IGND(BIAS)) vs Temperature
LP38852-ADJ 20213963.png
Figure 4. Load Regulation vs Temperature
LP38852-ADJ 20213966.png
Figure 6. Output Current Limit (ISC) vs Temperature
LP38852-ADJ 20213972.png
Figure 8. VOUT vs VIN
LP38852-ADJ 20213975.png
Figure 10. Soft-Start RSS Variation vs Temperature
LP38852-ADJ 20213988.png
Figure 12. Enable Thresholds (VEN) vs Temperature
LP38852-ADJ 20213990.png
Figure 14. Enable Pullup Resistor (REN) vs Temperature
LP38852-ADJ 20213978.png
Figure 16. VIN Line Transient Response
LP38852-ADJ 20213980.png
Figure 18. VBIAS Line Transient Response
LP38852-ADJ 20213971.png
Figure 20. VIN PSRR