Analog Devices ADP1872

Description

The ADP1872/ADP1873 are versatile current-mode, synchronous step-down controllers that provide superior transient response, optimal stability, and current limit protection by using a constant on-time, pseudo-fixed frequency with a programmable current-sense gain, current-control scheme. In addition, these devices offer optimum performance at low duty cycles by using valley current-mode control architecture. This allows the ADP1872/ADP1873 to drive all N-channel power stages to regulate output voltages as low as 0.6 V.

The ADP1873 is the power saving mode (PSM) version of the device and is capable of pulse skipping to maintain output regulation while achieving improved system efficiency at light loads (see the Power Saving Mode (PSM) Version (ADP1873) section for more information).Available in three frequency options (300 kHz, 600 kHz, and 1.0 MHz, plus the PSM option), the ADP1872/ADP1873 are well suited for a wide range of applications. These ICs not only operate from a 2.75 V to 5.5 V bias supply, but can also accept a power input as high as 20 V.In addition, an internally fixed, soft start period is included to limit input in-rush current from the input supply during startup and to provide reverse current protection during soft start for a pre-charged output. The low-side current-sense, current-gain scheme and integration of a boost diode, along with the PSM/forced pulse-width modulation (PWM) option, reduce the external part count and improve efficiency.The ADP1872/ADP1873 operate over the −40°C to +125°C junction temperature range and are available in a 10-lead MSOP.

Features

• Power input voltage as low as 2.75 V to 20 V
• Bias supply voltage range: 2.75 V to 5.5 V
• Minimum output voltage: 0.6 V
• 0.6 V reference voltage with ±1.0% accuracy
• Supports all N-channel MOSFET power stages
• Available in 300 kHz, 600 KHz, and 1.0 MHz options
• No current-sense resistor required
• Power saving mode (PSM) for light loads (ADP1873 only)
• Resistor-programmable current-sense gain
• Thermal overload protection
• Short-circuit protection
• Precision enable input
• Integrated bootstrap diode for high-side drive
• 140 μA shutdown supply current
• Starts into a precharged load
• Small, 10-lead MSOP package

Remarks:1.Table 7. Recommended InductorsRefer page no.23 And 31

2.Table 8. External Component Values RecommendedRefer page no.30

Typical applications

• Set-top boxes
• DSP core power supplies
• Mid to high end servers
• Telecom and networking systems

More information

• Datasheet
• IC product information