Texas Instruments LM5149-Q1EVM-400 Converter Evaluation Module

Texas Instruments LM5149-Q1EVM-400 Converter Evaluation Module (EVM) is designed to evaluate the features of the LM5149-Q1. The LM5149-Q1 is a synchronous buck DC/DC regulator that employs synchronous rectification to achieve high conversion efficiency in a small footprint. The free-running switching frequency of the Texas Instruments LM5149-Q1EVM-400 is 400kHz and is synchronizable to a higher or lower frequency if required. Moreover, a synchronization output signal (SYNCOUT) 180° phase-shifted relative to the internal clock is available for dual-phase leader-follower configurations. VCC and gate drive UVLO protects the regulator at low input voltage conditions and EN pins for each channel support application-specific power-up and power-down requirements.

Features

Wide input voltage (wide V_IN) range of 3.5V to 80V
Spread-spectrum modulation and active EMI filtering for lower EMI
Wide duty cycle range with low t_ON(min) and t_OFF(min)
Ultra-low shutdown and no-load standby quiescent currents
Multiphase capability

Peak current-mode control loop architecture
Integrated, high-current MOSFET gate drivers
Cycle-by-cycle overcurrent protection with hiccup
Functional-safety capable

Required Equipment

Voltage Source
- Use an input voltage source capable of supplying 0V to 80V and 12A
Multimeters
- Voltmeter 1
  - Input voltage at V_IN+ to V_IN–
  - Set the voltmeter to an input impedance of 100MΩ
- Voltmeter 2
  - Output voltage at V_OUT to GND
  - Set the voltmeter to an input impedance of 100MΩ
- Ammeter 1
  - Input current
  - Set the ammeter to a 1-second aperture time
- Ammeter 2
  - Output current
  - Set the ammeter to a 1-second aperture time
Electronic Load
- The load must be an electronic constant-resistance (CR) or constant-current (CC) mode load capable of 0A_DC to 10A_DC at 12V
- For a no-load input current measurement, disconnect the electronic load as it can draw a small residual current

Oscilloscope
- With the scope set to 20MHz bandwidth and AC coupling, measure the output voltage ripple directly across an output capacitor with a short ground lead generally provided with the scope probe
- Place the oscilloscope probe tip on the positive terminal of the output capacitor, holding the ground barrel of the probe through the ground lead to the negative terminal of the capacitor
- TI does not recommend using a long-leaded ground connection because this can induce additional noise given a large ground loop
- To measure other waveforms, adjust the oscilloscope as needed