SLUSCV7A July   2017  – August 2017 TPSM84203 , TPSM84205 , TPSM84212

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 Recommended Operating Conditions
    3. 6.3 ESD Ratings
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Switching Characteristics
    7. 6.7 Typical Characteristics (VOUT = 3.3 V)
    8. 6.8 Typical Characteristics (VOUT = 5 V)
    9. 6.9 Typical Characteristics (VOUT = 12 V)
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Input Capacitors
      2. 7.3.2 Output Capacitors
      3. 7.3.3 Drop-Out Voltage
      4. 7.3.4 Internal Soft-Start
      5. 7.3.5 Safe Startup into Pre-Biased Outputs
      6. 7.3.6 Over-Current Protection
      7. 7.3.7 Output Over-Voltage Protection
      8. 7.3.8 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Operation
      2. 7.4.2 Eco-mode 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 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Input and Output Capacitors
      3. 8.2.3 Application Curves
        1. 8.2.3.1 EMI
  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 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Custom Design With WEBENCH® Tools
    2. 11.2 Related Links
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7 Detailed Description

7.1 Overview

The TPSM84203, TPSM84205, and TPSM84212 devices are 28 V input, 1.5 A, synchronous step down converters with PWM, MOSFETs, inductor, and control circuitry integrated into a TO-220 footprint package. The device integration enables small designs, while improving efficiency over a traditional linear regulator design. The TPSM842xx family provides fixed output voltages of 3.3 V, 5.0 V and 12.0 V. The fixed 400 kHz (typ) switching frequency allows small size and low output voltage ripple. Under light load conditions, these devices are designed to operate in high-efficiency pulse-skipping mode. These devices provide accurate voltage regulation for a variety of loads by using a precision internal voltage reference. These devices have been designed to safely start up into a pre-biased output voltage. Thermal shutdown and current limit features protect the device during an overload condition. The 3-pin, TO-220 footprint package offers improved performance over traditional linear regulators packaged in the standard footprint.

7.2 Functional Block Diagram

TPSM84203 TPSM84205 TPSM84212 block_luscv7.gif

7.3 Feature Description

7.3.1 Input Capacitors

The TPSM842xx devices require a minimum input capacitance of 10 μF of ceramic type. High-quality ceramic type X5R or X7R capacitors with sufficient voltage rating are recommended. An additional 100 μF of non-ceramic capacitance is recommended for applications with transient load requirements. The voltage rating of input capacitors must be greater than the maximum input voltage.

Table 1. Recommended Input Capacitors(1)

VENDOR SERIES PART NUMBER CAPACITOR CHARACTERISTICS
WORKING VOLTAGE
(V)		 CAPACITANCE (3)
(µF)		 ESR(2)
(mΩ)
Murata X7R GRM32ER71H475KA88L 50 4.7 2
TDK X5R C3225X5R1H106K250AB 50 10 3
Murata X7R GRM32ER71H106KA12 50 10 2
TDK X7R C3225X7R1H106M250AB 50 10 3
Panasonic ZA EEHZA1H101P 50 100 28
(1) Consult capacitor suppliers regarding availability, material composition, RoHS and lead-free status, and manufacturing process requirements for any capacitors identified in this table.
(2) Maximum ESR @ 100kHz, 25°C.
(3) Standard capacitance values

7.3.2 Output Capacitors

The TPSM84203 and TPSM84205 devices require a minimum output capacitance of 94 μF (2x 47 μF) of ceramic type. The TPSM84212 device requires a minimum output capacitance of 47 μF of ceramic type. High-quality X5R or X7R ceramic capacitors with sufficient voltage rating are recommended. Additional output capacitance is recommended for applications with transient load requirements. The voltage rating of output capacitors must be greater than the maximum output voltage.

Table 2. Recommended Output Capacitors(1)

VENDOR SERIES PART NUMBER CAPACITOR CHARACTERISTICS
WORKING VOLTAGE
(V)		 CAPACITANCE (1)
(µF)		 ESR(2)
(mΩ)
TDK X5R C3225X5R0J476K 6.3 47 2
Murata X5R GRM32ER61C476K 16 47 3
TDK X5R C3225X5R0J107M 6.3 100 2
Murata X5R GRM32ER60J107M 6.3 100 2
Murata X5R GRM32ER61A107M 10 100 2
Kemet X5R C1210C107M4PAC7800 16 100 2
Panasonic POSCAP 6TPE100MI 6.3 100 18
Panasonic POSCAP 6TPF220M9L 6.3 220 9
Panasonic POSCAP 6TPE220ML 6.3 220 12
Panasonic POSCAP 6TPF330M9L 6.3 330 9
Panasonic POSCAP 16TQC47MYFD 16 47 55
(1) Standard capacitance values.

7.3.3 Drop-Out Voltage

The drop-out voltage of a voltage regulator is the difference between the input voltage and the output voltage that is required to maintain regulation. Figure 16 and Figure 17 show typical drop-out voltage graphs for TPSM84205 at ambient temperatures of 25°C and 85°C. Figure 18 and Figure 19 show typical drop-out voltage graphs for TPSM84212 at ambient temperatures of 25°C and 85°C.

TPSM84203 TPSM84205 TPSM84212 5VDropout25C.gif
1.
VOUT = 5.0 V TA = 25°C
Figure 16. Drop-Out Voltage
TPSM84203 TPSM84205 TPSM84212 12VDropO25C.gif
1.
VOUT = 12 V TA = 25°C
Figure 18. Drop-Out Voltage
TPSM84203 TPSM84205 TPSM84212 5VDropout85C.gif
1.
VOUT = 5.0 V TA = 85°C
Figure 17. Drop-Out Voltage
TPSM84203 TPSM84205 TPSM84212 12VDrop85C.gif
1.
VOUT = 12 V TA = 85°C
Figure 19. Drop-Out Voltage

7.3.4 Internal Soft-Start

The device starts up under control of the internal soft-start function. The internal soft start time is set to 5 ms typically.

7.3.5 Safe Startup into Pre-Biased Outputs

The device has been designed to prevent the low-side MOSFET from discharging a pre-biased output. During monotonic pre-biased startup, both high-side and low-side MOSFETs are not allowed to be turned on until the internal soft-start voltage is higher than the internal feedback voltage.

7.3.6 Over-Current Protection

The device is protected from overcurrent conditions by cycle-by-cycle current limiting. If an output overload condition occurs for more than 1.28 ms, the device shuts down and restarts after approximately 40 ms. The hiccup mode helps to reduce the device power dissipation under severe overcurrent conditions.

7.3.7 Output Over-Voltage Protection

An output over voltage protection circuit is incorporated to minimize output voltage overshoot when recovering from output fault conditions or strong unload transients. When the output voltage goes above 108% × VOUT, the high-side MOSFET is forced off. When the output voltage falls below 104% × VOUT, the high-side MOSFET is enabled again.

7.3.8 Thermal Shutdown

The internal thermal-shutdown circuitry forces the device to stop switching if the junction temperature exceeds 165°C typically. The device reinitiates the power-up sequence when the junction temperature drops below 155°C typically.

7.4 Device Functional Modes

7.4.1 Normal Operation

The TPSM842xx devices operate in Normal operation mode when the input voltage is above the minimum input voltage. In Normal operation mode, the device operates in continuous conduction mode (CCM) which occurs when inductor peak current is above 840 mA typically. In CCM, the TPSM842xx devices operate at a fixed frequency of 400 kHz (typ). In addition, to reduce EMI, the devices introduce frequency spread spectrum. The jittering frequency range is ±6% of the switching frequency with a 780 Hz modulation rate.

7.4.2 Eco-mode™ Operation

The TPSM842xx devices operate in Eco-mode operation in light load conditions. Eco-mode is a high-efficiency, pulse-skipping mode under light load conditions. Pulse skipping initiates when the switch current falls to 840 mA typically. During pulse skipping, the low-side FET turns off when the switch current falls to 0 A. The device takes on the characteristics of discontinuous conduction mode (DCM) operation and the apparent switching frequency decreases. As the output current decreases, the perceived time between switching pulses increases.