ZHCSFB5D July 2016 – December 2017 LM5141-Q1
PRODUCTION DATA.
The VCC regulator output current limit is 75 mA (minimum). At power-up, the regulator sources current into the capacitors connected to the VCC pin. When the voltage on the VCC pin exceeds 3.4 V the output is enabled and the soft-start sequence begins. The output remains active unless the voltage on the VCC pin falls below the VCC(UVLO) threshold of 3.2 V (typical) or the enable pin is switched to a low state. The recommended range for the VCC capacitor is 2.2 µF to 4.7 µF
An internal 5-V linear regulator generates the VDDA bias supply. Bypass VDDA with a 100-nF or greater ceramic capacitor to ensure a low noise internal bias rail. Normally VDDA is 5 V, but there are two operating conditions where it regulates at 3.3 V. The first is in skip cycle mode with VOUT of 3.3 V. The second is when VIN is less than 5 V. Under these conditions both VCC and VDD drop below 5 V. Internal power dissipation in the VCC Regulator can be minimized by connecting the VCCX pin to a 5-V output or to an external 5-V supply. If VCCX > 4.5 V, VCCX is internally connected to VCC and the internal VCC regulator is disabled. If VCCX is unused, it should be grounded. Never connect the VCCX pin to a voltage greater than 6.5 V.