SLVSI74A July 2025 – November 2025 TLV61290
PRODUCTION DATA
The first step of circuit and stability evaluation is to look from a steady-state perspective at the following signals:
These are the basic signals that need to be measured when evaluating a switching converter. Signs of instability in the regulation loop include switching waveforms showing large duty cycle jitter, or the output voltage or inductor current showing oscillations. This is often a result of board layout and/or L-C combination.
As a next step in the evaluation of the regulation loop, the load transient response is tested. The time between the application of the load transient and the turn on of the P-channel MOSFET, enable the output capacitor to supply all of the current required by the load. VOUT immediately shifts by an amount equal to ΔI(LOAD) x ESR, where ESR is the effective series resistance of COUT. ΔI(LOAD) begins to charge or discharge COUT generating a feedback error signal used by the regulator to return VOUT to its steady-state value. The results are most easily interpreted when the device operates in PWM mode.
During this recovery time, monitor VOUT for settling time, overshoot or ringing that helps judge the stability of the converter. Without any ringing, the loop has usually more than 45° of phase margin. Because the damping factor of the circuitry is directly related to several resistive parameters (that is, MOSFET rDS(on)) that are temperature dependent, the loop stability analysis has to be done over the input voltage range, load current range, and temperature range.
The TLV61290 series of step-up converters have been optimized to operate with a effective inductance in the range of 330nH to 560nH and with output capacitors in the range of 11µF to 100µF. The internal compensation is optimized for an output filter of L = 0.47µH and effective CO = 14µF.
| REFERENCE | DESCRIPTION | PART NUMBER, MANUFACTURER(1) |
|---|---|---|
| CIN | 22μF, 10V, 0603, X5R ceramic | GRM187R61A226ME15D |
| COUT | 2 x 22μF, 10V, 0603, X5R ceramic | 2 x GRM187R61A226ME15D |
| L | 450nH, 13.8mΩ, 4.0mm x 4.0mm x 1.2mm | XGL4012-451 |