Quad, 1 A, 5.5 V, Synchronous Step-Down

Regulators with One RF LDO Regulator

Data Sheet

ADP5138

Rev. A

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FEATURES

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

Integrated compensation

Soft start and power-up sequencing reduce inrush current

Active output discharge switch function

Stable with low ESR output ceramic capacitors

OVLO, UVM, and UVLO

TSD protection

Qualified for automotive applications

APPLICATIONS

Automotive

Industrial and instrumentation

DC to dc point of load applications

TYPICAL APPLICATION CIRCUIT

Figure 1.

GENERAL DESCRIPTION

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.

PVIN1

EN1

SW1

FB1

PGND1

SW2

FB2

PGND2

SW3

FB3

PGND3

L3

SW4

FB4

L4

PGND4

PVIN2

EN2

PVIN3

EN3

PVIN4

EN4

PVIN5

EN5

VOUT5

AVIN

POR

POR

FB5

GND

SYNC

ADP5138

L2

L1