Quad, 1 A, 5.5 V, Synchronous Step-Down Regulators with One RF LDO Regulator

The ADP5138 integrates four high performance synchronous step-down regulators and one low noise radio frequency (RF) low dropout (LDO) regulator. The device runs from PVINx input voltages of 3 V to 5.5 V. The output voltage of each channel is factory set or can be programmed down to 0.8 V with a resistor. Each step-down regulator can provide up to 1 A of continuous output current and the LDO can provide 250 mA of output current.

The ADP5138 runs at the fixed PWM switching frequency, 3.2 MHz, or can be synchronized to the external clock from 2.8 MHz to 3.5 MHz, which is outside the amplitude modulation (AM) band. The four buck regulators run at 90° out of phase to reduce the input ripple current and the input capacitor size, thereby helping to lower system electromagnetic interference (EMI).

The ADP5138 integrates internal compensation to simplify the design. The internal soft start circuitry and power-up sequencing help reduce the input inrush current.

The ADP5138 monitors the input voltage and provides input overvoltage lockout (OVLO), undervoltage monitor (UVM), and undervoltage lockout (UVLO) features. It also monitors the undervoltage and overvoltage of the outputs. The power-on reset (POR) signal is asserted when the input or output voltage fault occurs.

Additional protection includes overcurrent protection (OCP) and thermal shutdown (TSD).

The ADP5138 operates over the −40°C to +125°C operating temperature range (junction), and is available in a 28-lead LFCSP package.

APPLICATIONS

* Automotive

* Industrial and instrumentation

* DC-to-dc point of load application

* PVINx voltage range: 3 V to 5.5 V

* Continuous output current

* Channel 1 to Channel 4 (buck): 1 A

* Channel 5 (LDO): 250 mA

* 3.2 MHz fixed PWM switching frequency

* Synchronization input function

* Buck regulators run at 90° out of phase

* Individual precision enable input

* Power-on reset output