48-V Output Low-Noise Phantom Power Reference Design

1 Description

This reference design delivers a 48-V output, low-noise power supply for the phantom power application using the TPS61391 and TPS7A4101 devices. The TPS61391 is a 700-kHz PWM step-up converter that converts
3.3 V or 5 V to 48.5 V. The TPS7A4101 is a 50-V tolerant input and 0.29-V drop LDO that steps 48.5 V down to 48 V and minimizes the output ripple. The design supports 48-V, 20-mA output power at 5-V input. The output ripple is only around 8.4 mV, which is pretty low for phantom power applications.

Figure 1-1 Top Photo

Figure 1-2 Block Diagram

2 Test Prerequisites

2.1 Voltage and Current Requirements

Table 2-1 Voltage and Current Requirements

Parameter	Specifications
Input Voltage	3.3-5 VDC
Output Voltage	48 VDC
Output Current	10-mA at 3.3-VDC input 20-mA at 5-VDC input

Parameter

Specifications

Input Voltage

3.3-5 VDC

Output Voltage

48 VDC

Output Current

10-mA at 3.3-VDC input

20-mA at 5-VDC input

2.2 Required Equipment

Multimeter (current): Fluke 287C
Multimeter (voltage): Fluke 287C
DC Source: Chroma MODEL 62012P-100-50
E-Load: Chroma 63110A
Oscilloscope: Tektronix DPO3054
Electrical Thermography: Fluke TiS65

2.3 Dimensions

The board dimensions are 58.4 mm (length) × 30.5 mm (width) × 8.4 mm (height).