SLLS636N December   2004  – January 2015 MC33063A , MC34063A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Description
  3. 3 Simplified Schematic
  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—Oscillator
    6. 6.6 Electrical Characteristics—Output Switch
    7. 6.7 Electrical Characteristics—Comparator
    8. 6.8 Electrical Characteristics—Total Device
    9. 6.9 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
      1. 7.4.1 Standard operation
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 External Switch Configurations for Higher Peak Current
    2. 8.2 Typical Application
      1. 8.2.1 Voltage-Inverting Converter Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Performance
      2. 8.2.2 Step-Up Converter Application
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Performance
      3. 8.2.3 Step-Down Converter Application
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
        3. 8.2.3.3 Application Performance
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Related Links
    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

8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

8.1 Application Information

8.1.1 External Switch Configurations for Higher Peak Current

up_i_boost_lls636.gif
A. If the output switch is driven into hard saturation (non-Darlington configuration) at low switch currents (≤300 mA) and high driver currents (≥30 mA), it may take up to 2 μs to come out of saturation. This condition will shorten the off time at frequencies ≥30 kHz and is magnified at high temperatures. This condition does not occur with a Darlington configuration because the output switch cannot saturate. If a non-Darlington configuration is used, the output drive configuration in Figure 7b is recommended.
Figure 5. Boost Regulator Connections for IC Peak Greater Than 1.5 A
down_i_boost_lls636.gifFigure 6. Buck Regulator Connections for IC Peak Greater Than 1.5 A
ext_curr_boost_icpeak_gt_1p5a_lls636.gifFigure 7. Inverting Regulator Connections for IC Peak Greater Than 1.5 A

8.2 Typical Application

8.2.1 Voltage-Inverting Converter Application

inverting_lls636.gifFigure 8. Voltage-Inverting Converter

8.2.1.1 Design Requirements

The user must determine the following desired parameters:

Vsat = Saturation voltage of the output switch

VF = Forward voltage drop of the chosen output rectifier

The following power-supply parameters are set by the user:

Vin = Nominal input voltage

Vout = Desired output voltage

Iout = Desired output current

fmin = Minimum desired output switching frequency at the selected values of Vin and Iout

Vripple = Desired peak-to-peak output ripple voltage. The ripple voltage directly affects the line and load regulation and, thus, must be considered. In practice, the actual capacitor value should be larger than the calculated value, to account for the capacitor's equivalent series resistance and board layout.

8.2.1.2 Detailed Design Procedure

CALCULATION VOLTAGE INVERTING
ton/toff q_tonoff_inv_lls636.gif
(ton + toff) q_ton_off_in_lls636.gif
toff q_toff_inv_lls636.gif
ton q_ton_inv_lls636.gif
CT q_ct_inv_lls636.gif
Ipk(switch) q_ipk_inv_lls636.gif
RSC q_rsc_inv_lls636.gif
L(min) q_lmin_inv_lls636.gif
CO q_co_inv_lls636.gif
Vout q_vout_inv_lls636.gif
See Figure 8

8.2.1.3 Application Performance

g_vipk_ta_lls636.gifFigure 9. Current-Limit Sense Voltage vs Temperature
TEST CONDITIONS RESULTS
Line regulation VIN = 4.5 V to 6 V, IO = 100 mA 3 mV ± 0.12%
Load regulation VIN = 5 V, IO = 10 mA to 100 mA 0.022 V ± 0.09%
Output ripple VIN = 5 V, IO = 100 mA 500 mVPP
Short-circuit current VIN = 5 V, RL = 0.1 Ω 910 mA
Efficiency VIN = 5 V, IO = 100 mA 62.2%
Output ripple with optional filter VIN = 5 V, IO = 100 mA 70 mVPP

8.2.2 Step-Up Converter Application

stepup_lls636.gifFigure 10. Step-Up Converter

8.2.2.1 Design Requirements

The user must determine the following desired parameters:

Vsat = Saturation voltage of the output switch

VF = Forward voltage drop of the chosen output rectifier

The following power-supply parameters are set by the user:

Vin = Nominal input voltage

Vout = Desired output voltage

Iout = Desired output current

fmin = Minimum desired output switching frequency at the selected values of Vin and Iout

Vripple = Desired peak-to-peak output ripple voltage. The ripple voltage directly affects the line and load regulation and, thus, must be considered. In practice, the actual capacitor value should be larger than the calculated value, to account for the capacitor's equivalent series resistance and board layout.

8.2.2.2 Detailed Design Procedure

CALCULATION STEP UP
ton/toff q_tonoff_up_lls636.gif
(ton + toff) q_ton_off_up_lls636.gif
toff q_toff_up_lls636.gif
ton q_ton_up_lls636.gif
CT q_ct_up_lls636.gif
Ipk(switch) q_ipk_up_lls636.gif
RSC q_rsc_up_lls636.gif
L(min) q_lmin_up_lls636.gif
CO q_co_up_lls636.gif
Vout q_vout_up_lls636.gif
See Figure 10

8.2.2.3 Application Performance

TEST CONDITIONS RESULTS
Line regulation VIN = 8 V to 16 V, IO = 175 mA 30 mV ± 0.05%
Load regulation VIN = 12 V, IO = 75 mA to 175 mA 10 mV ± 0.017%
Output ripple VIN = 12 V, IO = 175 mA 400 mVPP
Efficiency VIN = 12 V, IO = 175 mA 87.7%
Output ripple with optional filter VIN = 12 V, IO = 175 mA 40 mVPP

8.2.3 Step-Down Converter Application

stepdown_lls636.gifFigure 11. Step-Down Converter

8.2.3.1 Design Requirements

The user must determine the following desired parameters:

Vsat = Saturation voltage of the output switch

VF = Forward voltage drop of the chosen output rectifier

The following power-supply parameters are set by the user:

Vin = Nominal input voltage

Vout = Desired output voltage

Iout = Desired output current

fmin = Minimum desired output switching frequency at the selected values of Vin and Iout

Vripple = Desired peak-to-peak output ripple voltage. The ripple voltage directly affects the line and load regulation and, thus, must be considered. In practice, the actual capacitor value should be larger than the calculated value, to account for the capacitor's equivalent series resistance and board layout.

8.2.3.2 Detailed Design Procedure

CALCULATION STEP DOWN
ton/toff q_tonoff_dwn_lls636.gif
(ton + toff) q_ton_off_dn_lls636.gif
toff q_toff_dwn_lls636.gif
ton q_ton_dwn_lls636.gif
CT q_ct_dwn_lls636.gif
Ipk(switch) q_ipk_dwn_lls636.gif
RSC q_rsc_dwn_lls636.gif
L(min) q_lmin_dwn_lls636.gif
CO q_co_dwn_lls636.gif
Vout q_vout_dwn_lls636.gif
See Figure 11

8.2.3.3 Application Performance

TEST CONDITIONS RESULTS
Line regulation VIN = 15 V to 25 V, IO = 500 mA 12 mV ± 0.12%
Load regulation VIN = 25 V, IO = 50 mA to 500 mA 3 mV ± 0.03%
Output ripple VIN = 25 V, IO = 500 mA 120 mVPP
Short-circuit current VIN = 25 V, RL = 0.1 Ω 1.1 A
Efficiency VIN = 25 V, IO = 500 mA 83.7%
Output ripple with optional filter VIN = 25 V, IO = 500 mA 40 mVPP