SLUSC78A November   2015  – December 2015 TPS548A20

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 Electrical Characteristics
    5. 6.5 Thermal Information
    6. 6.6 Typical Characteristics
    7. 6.7 Thermal Performance
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1  Powergood
      2. 7.3.2  D-CAP3 Control and Mode Selection
      3. 7.3.3  D-CAP3 Mode
      4. 7.3.4  Sample and Hold Circuitry
      5. 7.3.5  Adaptive Zero-Crossing
      6. 7.3.6  Forced Continuous-Conduction Mode
      7. 7.3.7  Current Sense and Overcurrent Protection
      8. 7.3.8  Overvoltage and Undervoltage Protection
      9. 7.3.9  Out-of-Bounds Operation (OOB)
      10. 7.3.10 UVLO Protection
      11. 7.3.11 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Auto-Skip Eco-Mode Light-Load Operation
      2. 7.4.2 Forced Continuous-Conduction 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 Choose the Switching Frequency
        2. 8.2.2.2 Choose the Operation Mode
        3. 8.2.2.3 Choose the Inductor
        4. 8.2.2.4 Choose the Output Capacitor
        5. 8.2.2.5 Determine the Value of R1 and R2
      3. 8.2.3 Application Curves
  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 Documentation Support
    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

5 Pin Configuration and Functions

28-PIN
QFN
(TOP VIEW)
TPS548A20 pinout_rve28_slusc78.gif

Pin Functions

PIN I/O(1) DESCRIPTION
NAME NO.
EN 3 I The enable pin turns on the DC-DC switching converter.
FB 23 I VOUT feedback input. Connect this pin to a resistor divider between the VOUT pin and GND.
GND 22 G This pin is the ground of internal analog circuitry and driver circuitry. Connect GND to the PGND plane with a short trace (For example, connect this pin to the thermal pad with a single trace and connect the thermal pad to PGND pins and PGND plane).
GND1 27 G Connect this pin to ground. GND1 is the input of unused internal circuitry and must connect to ground.
GND2 28
MODE 21 I The MODE pin sets the forced continuous-conduction mode (FCCM) or auto-skip mode operation. It also selects the ramp coefficient of D-CAP3 mode.
NC 5 — Not connected. These pins are floating internally.
18
26
PGND 10 G These ground pins are connected to the return of the internal low-side MOSFET.
11
12
13
14
PGOOD 2 O Open-drain power-good status signal which provides startup delay after the FB voltage falls within the specified limits. After the FB voltage moves outside the specified limits, PGOOD goes low within 2 µs.
RF 1 I
SW 6 I/O SW is the output switching terminal of the power converter. Connect this pin to the output inductor.
7
8
9
TRIP 25 I/O TRIP is the OCL detection threshold setting pin. ITRIP = 10 µA at TA = 25°C, 3000 ppm/°C current is sourced and sets the OCL trip voltage. See the Current Sense and Overcurrent Protection section for detailed OCP setting.
VBST 4 P VBST is the supply rail for the high-side gate driver (boost terminal). Connect the bootstrap capacitor from this pin to the SW node. Internally connected to VREG via bootstrap PMOS switch.
VDD 19 P Power-supply input pin for controller. Input of the VREG LDO. The input range is from 4.5 to 25 V.
VIN 15 P VIN is the conversion power-supply input pins.
16
17
VREG 20 O VREG is the 5-V LDO output. This voltage supplies the internal circuitry and gate driver.
VO 24 I VOUT voltage input to the controller.
(1) I = Input, O = Output, P = Supply, G = Ground