SNVS782C October   2010  – August 2015 LM3243

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 System Characteristics
    7. 6.7 Timing Requirements
    8. 6.8 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 ACB
      2. 7.3.2 Bypass Operation
      3. 7.3.3 Mode Pin
      4. 7.3.4 Dynamic Adjustment Of Output Voltage
      5. 7.3.5 Internal Synchronous Rectification
      6. 7.3.6 Current Limit
      7. 7.3.7 Timed Current Limit
      8. 7.3.8 Thermal Overload Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 PWM Operation
      2. 7.4.2 PFM Mode
      3. 7.4.3 Mode Selection
      4. 7.4.4 Shutdown Mode
  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 Inductor Selection
        2. 8.2.2.2 Capacitor Selection
        3. 8.2.2.3 Setting The Output Voltage
          1. 8.2.2.3.1 DAC Control
          2. 8.2.2.3.2 PDM-Based VCON Signal
          3. 8.2.2.3.3 VCON Pin
        4. 8.2.2.4 EN Input Control
        5. 8.2.2.5 Start-Up
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 PCB Considerations
        1. 10.1.1.1 Energy Efficiency
        2. 10.1.1.2 EMI
      2. 10.1.2 Manufacturing Considerations
    2. 10.2 Layout Example
      1. 10.2.1 LM3243 RF Evaluation Board
      2. 10.2.2 DC-DC Converter Section
      3. 10.2.3 VBATT Star Supply Connection
    3. 10.3 DSBGA Package Assembly and Use
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 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
VDD, PVIN to SGND −0.2 6 V
PGND to SGND −0.2 0.2 V
EN, FB, VCON, BP, MODE (SGND − 0.2) (VDD + 0.2) V
SW, ACB (PGND − 0.2) (PVIN + 0.2) V
PVIN to VDD −0.2 0.2 V
Continuous power dissipation(4) Internally limited
Junction temperature, TJ-MAX 150 °C
Maximum lead temperature  (soldering, 10 sec) 150 °C
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) Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Recommended Operating Conditions are conditions under which operation of the device is specified. Operating Ratings do not imply verified performance limits. For performance limits and associated test conditions, see Electrical Characteristics.
(3) All voltages are with respect to the potential at the GND pins. The LM3243 is designed for mobile phone applications where turnon after power-up is controlled by the system controller and where requirements for a small package size overrule increased die size for internal undervoltage lock-out (UVLO) circuitry. Thus, it should be kept in shutdown by holding the EN pin LOW until the input voltage exceeds 2.7 V.
(4) Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ = 150°C (typical) and disengages at TJ = 130°C (typical).

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)(1)(2)
MIN NOM MAX UNIT
Input voltage 2.7 5.5 V
Recommended load current 2.5 A
Junction temperature, TJ −30 125 °C
Ambient temperature, TA(3) −30 90 °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 the potential at the GND pins. The LM3243 is designed for mobile phone applications where turnon after power up is controlled by the system controller and where requirements for a small package size overrule increased die size for internal undervoltage lock-out (UVLO) circuitry. Thus, it should be kept in shutdown by holding the EN pin LOW until the input voltage exceeds 2.7 V.
(3) In applications where high-power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may have to be de-rated. Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP = 125°C), the maximum power dissipation of the device in the application (PD-MAX), and the junction-to ambient thermal resistance of the part/package in the application (RθJA), as given by the following equation: TA-MAX = TJ-MAX-OP – (RθJA × PD-MAX). At higher power levels duty cycle usage is assumed to drop (that is, max power 12.5% usage is assumed) for 2G mode.

6.4 Thermal Information

THERMAL METRIC(1) LM3243 UNIT
TMD (DSBGA)
16 PINS
RθJA Junction-to-ambient thermal resistance 50 °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 noted, all specifications apply to Typical System Application Diagram with: PVIN = VDD = EN = 3.8 V,
BP = 0 V. All typical (TYP) limits apply for TA = TJ = 25°C, and all minimum (MIN) and maximum (MAX) apply over the full operating ambient temperature range (−30°C ≤ TA = TJ ≤ +90°C), unless otherwise specified.(1)(2)(3)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
VFB, LOW Feedback voltage at low setting VCON = 0.16 V, MODE = LOW(3) 0.35 0.40 0.45 V
VFB, HIGH Feedback voltage at high setting VCON = 1.44 V, VIN = 3.9 V,
MODE = LOW(3)		 3.492 3.6 3.708 V
ISHDN Shutdown supply current EN = SW = VCON = 0 V(4) 0.02 4 µA
Iq_PFM DC bias current into VDD No switching(5)
MODE = HIGH		 260 310 µA
Iq_PWM DC bias current into VDD No switching(5)
MODE = LOW		 975 1100 µA
ILIM,PFET,Transient Positive transient peak current limit VCON = 0.6 V(6) 1.9 2.1 A
ILIM,PFET,Steady State Positive steady-state peak current limit VACB = 3.05 V
VCON = 0.6 V(6)		 1.34 1.45 1.65 A
ILIM, P_ACB Positive active current assist peak current limit VCON = 0.6 V, VACB = 2.8 V(6) 1.4 1.7 2 A
ILIM, NFET NFET switch negative peak current limit VCON = 1 V(6) −1.69 −1.50 −1.31 A
FOSC Average Internal oscillator frequency VCON = 1 V 2.43 2.7 2.97 MHz
VIH Logic HIGH input threshold BP, EN, MODE 1.2 V
VIL Logic LOW input threshold BP, EN, MODE 0.5 V
IEN EN pin pulldown current EN = 3.6 V 0 5 10 µA
IIN Pin input current BP, MODE –1 1 µA
IVCON VCON pin leakage current VCON = 1 V –1 1 µA
Gain VCON to VOUT Gain 0.16 V ≤ VCON ≤ 1.44 V(7) 2.5 V/V
(1) All voltages are with respect to the potential at the GND pins. The LM3243 is designed for mobile phone applications where turnon after power up is controlled by the system controller and where requirements for a small package size overrule increased die size for internal undervoltage lock-out (UVLO) circuitry. Thus, it should be kept in shutdown by holding the EN pin LOW until the input voltage exceeds 2.7 V.
(2) Minimum and Maximum limits are specified by design, test, or statistical analysis.
(3) The parameters in the electrical characteristics table are tested under open loop conditions at PVIN = VDD = 3.8 V. For performance over the input voltage range and closed-loop results, refer to the datasheet curves.
(4) Shutdown current includes leakage current of PFET.
(5) Iq specified here is when the part is not switching. For operating input current at no load, refer to datasheet curves.
(6) Current limit is built-in, fixed, and not adjustable.
(7) Linearity limits are ±3% or ±50 mV, whichever is larger.

6.6 System Characteristics

The following spec table entries are specified by design and verifications providing the component values in the Typical System Application Diagram are used (L = 1.5 µH, DCR = 120 mΩ, TOKO DFE201610C-1R5N, CIN = 10 µF, 6.3 V, 0402, Samsung CL05A106MQ5NUN, COUT = 10 µF + 4.7 µF + 3 × 1 µF + 3300 pF: 6.3 V, 0402, Samsung CL05A106MQ5NUN, CL05A475MQNRN; 6.3 V, 0201 Samsung CL03A105MQ3CSN; 6.3 V, 01005 Murata GRM022R60J332K). These parameters are not verified by production testing. Minimum (MIN) and maximum (MAX) values are specified over the ambient temperature range TA = −30°C to 90°C. Typical (TYP) values are specified at PVIN = VDD = EN = 3.8 V, BP = 0 V and TA = 25°C unless otherwise stated.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Rtot_drop Total dropout resistance in bypass mode VCON = 1.5 V
Max value at VIN = 3.1 V
Inductor ESR ≤ 151 mΩ		 45 55 mΩ
CIN Pin input capacitance for BP, EN, MODE Test frequency = 100 KHz 5 pF
IOUT Maximum load current in PWM mode Switcher + ACB 2.5 A
IOUT, PU Maximum output transient pullup current limit Switcher + ACB(1) 3
IOUT, PD, PWM PWM maximum output transient pulldown current limit −3
IOUT, MAX-PFM Maximum output load current in PFM mode VIN = 3.8 V, VCON < 1
MODE = HIGH(1)		 85 mA
Linearity Linearity in control range of
VCON = 0.16 V to 1.44 V 		VIN = 4.2 V(2)
Monotonic in nature		 −3% 3%
−50 50 mV
η Efficiency VIN = 3.8 V, VOUT = 1.8 V
IOUT = 10 mA
MODE = HIGH (PFM)		 79% 82%
VIN = 3.8 V, VOUT = 0.5 V
IOUT = 5 mA
MODE = HIGH (PFM) 		58% 60%
VIN = 3.8 V, VOUT = 3.5 V
IOUT = 1900 mA
MODE = LOW (PWM) 		89% 92%
VIN = 3.8 V, VOUT = 2.5 V
IOUT = 250 mA
MODE = LOW (PWM)		 90% 93%
VIN = 3.8 V, VOUT = 1.6 V
IOUT = 130 mA
MODE = LOW (PWM)		 83% 86%
VIN = 3.8 V, VOUT = 1 V
IOUT = 400 mA
MODE = LOW (PWM)		 81% 84%
VRIPPLE Ripple voltage at no pulse skipping condition VIN = 0.4 V to 3.6 V
VOUT = 0.4 V to 3.6 V,
ROUT = 1.9 Ω(3)
MODE = LOW 		1 3 mVpp
Ripple voltage at pulse skipping condition VIN = 5.5 V to dropout, VOUT = 3.6 V, ROUT = 1.9 Ω(3) 8
PFM ripple voltage VIN = 3.2 V, VOUT < 1.125 V
IOUT =10 mA, MODE = HIGH		 50
VIN = 3.2 V, VOUT ≤ 0.5 V,
IOUT = 5 mA
MODE = HIGH		 50
Line_tr Line transient response VIN = 3.6 V to 4.2 V, TR = TF = 10 µs, VOUT = 1 V
IOUT = 600 mA, MODE = LOW		 50 mVpk
Load_tr Load transient response VOUT = 3 V, TR = TF = 10 µs
IOUT = 0 A to 1.2 A
MODE = LOW		 40 mVpk
Maximum Duty Cycle Maximum duty cycle MODE = LOW 100%
PFM_Freq Minimum PFM frequency VIN = 3.2 V, VOUT = 1 V
IOUT = 10 mA, MODE = HIGH		 100 160 kHz
VIN = 3.2 V, VOUT = 0.5 V
IOUT = 5 mA, MODE = HIGH		 34 55
(1) Current limit is built-in, fixed, and not adjustable.
(2) Linearity limits are ±3% or ±50 mV, whichever is larger.
(3) Ripple voltage should be measured at COUT electrode on a well-designed PC board and using the suggested inductor and capacitors.

6.7 Timing Requirements

MIN MAX UNIT
tSETUP Time for SW pin to become active upon power up; EN = LOW-to-HIGH 30 µs
tON Turnon time (time for output to reach 90% of final value after EN LOW-to-HIGH transition)
EN = LOW-to-HIGH, VIN = 4.2 V, VCON = 1.36 V, VOUT = 3.4 V, IOUT ≤ 1 mA		 50 µs
tRESPONSE Time for VOUT to rise from 0 V to 3 V (90% or 2.7 V);
VIN = 4.2 V, RLOAD = 6.8 Ω, VCON = 0 V to 1.2 V		 20 µs
Time for VOUT to fall from 3.6 V to 2.6 V (10% or 2.7 V)
VIN = 4.2 V, RLOAD = 6.8 Ω, VCON = 1.44 V to 1.04 V		 20
Time for VOUT to rise from 1.8 V to 2.8 V (90% or 2.7 V)
VIN = 4.2 V, RLOAD = 1.9 Ω, VCON = 0.72 V to 1.12 V		 15
Time for VOUT to fall from 2.8 V to 1.8 V (10% or 1.9 V)
VIN = 4.2 V, RLOAD = 1.9 Ω, VCON = 1.12 V to 0.72 V		 15
Time for VOUT to rise from 0 V to 3.4 V (90% or 3.1 V)
VIN = 4.2 V, RLOAD = 1.9 Ω, VCON = 0 V to 1.36 V		 20
Time for VOUT to fall from 3.4 V to 0.4 V (10% or 0.7 V)
VIN = 4.2 V, RLOAD = 1.9 Ω, VCON = 1.36 V to 0.16 V		 20
tBypass Time for VOUT to rise from 0 V to PVIN after BP LOW-to-HIGH transition (90%)
VCON = 0 V, IOUT ≤ 1 mA		 20 µs
tBypass, ON Bypass turnon time. Time for VOUT to rise from 0 V to PVIN after EN LOW-to-HIGH transition (90% or 3.24)
EN = VIN= 3.8 V, IOUT ≤ 1 mA		 50 µs

6.8 Typical Characteristics

LM3243 30132135.gif
VOUT = 3.4 V VIN = 4.3 V down to Dropout
Figure 1. Output Voltage vs. Supply Voltage
LM3243 30132137.gif
VIN = 3.8 V VOUT = 2.5 V IOUT = 700 mA
Figure 3. Center-Switching Frequency vs. Supply Voltage
LM3243 30132139.gif
2.7 V < VIN< 5.5 V (No Load) VOUT = 2.5 V
Figure 5. Quiescent Current (PWM) vs. Supply Voltage
LM3243 30132120.gif
VIN = 4.2 V RLOAD = 1.9 Ω VOUT = 1.4 V to 3.4 V
Figure 7. VCON Transient (PWM)
LM3243 30132123.gif
VIN = 3.8 V VOUT = 2.5 V IOUT = 0 mA to 300 mA
Figure 9. Load Transient In PWM Mode
LM3243 30132125.gif
VIN = 4.2 V VOUT = 3 V IOUT = 0 mA to 1.2 A
Figure 11. Load Transient In PWM Mode
LM3243 30132127.gif
VIN = 3.6 V to 4.2 V RLOAD = 6.8 Ω VOUT = 1 V
Figure 13. Line Transient
LM3243 30132129.gif
VIN = 4.2 V VOUT = 3.4 V No load, EN = Low-to-High
Figure 15. Start-up In PWM Mode
LM3243 30132136.gif
VIN = 4.2 V RLOAD = 6.8 Ω 0.16 V < VCON < 1.4 V
Figure 2. Output Voltage vs. VCON Voltage
LM3243 30132138.gif
2.7 V < VIN< 5.5 V (No Load) VOUT = 1 V
Figure 4. Quiescent Current (PFM) vs. Supply Voltage
LM3243 30132119.gif
VIN = 3.8 V RLOAD = 6.8 Ω VOUT = 0 V to 3 V
Figure 6. VCON Transient (3G/4G)
LM3243 30132122.gif
VIN = 3.6 V VOUT = 1 V IOUT = 0 mA to 60 mA
Figure 8. Load Transient In PFM Mode
LM3243 30132124.gif
VIN = 3.8 V VOUT = 3 V IOUT = 0 mA to 700 mA
Figure 10. Load Transient In PWM Mode
LM3243 30132126.gif
VIN = 3.6 V to 4.2 V RLOAD = 6.8 Ω VOUT = 2.5 V
Figure 12. Line Transient
LM3243 30132128.gif
VIN = 3.8 V VOUT = 1 V No load, EN = Low-to-High
Figure 14. Start-up in PFM Mode
LM3243 30132130.gif
VIN = 4.2 V RLOAD = 6.8 Ω to VOUT Shorted VOUT = 2.5 V
Figure 16. Timed-Current Limit