Analog Devices ADP1878

Description

The ADP1878/ADP1879 are versatile current-mode, synchronous step-down controllers. They provide superior transient response, optimal stability, and current-limit protection by using a constant on time, pseudo fixed frequency with a programmable current-limit,current control scheme. These devices offer optimum performanceat low duty cycles by using a valley, current-mode control architecture allowing the ADP1878/ADP1879 to drive all N-channel power stages to regulate output voltages to as low as 0.6 V.

The ADP1879 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 ADP1879 Power Saving Mode (PSM) section for more information).

Available in three frequency options (300 kHz, 600 kHz, and 1.0 MHz) plus the PSM option, the ADP1878/ADP1879 are well suited for a wide range of applications that require a single input power supply range from 2.95 V to 20 V. Low voltage biasing is supplied via a 5 V internal low dropout regulator (LDO). In addition, soft start programmability is included to limit input inrush current from the input supply during startup and to provide reverse current protection during precharged output conditions. The low-side current sense, current gain scheme and integration of a boost diode, together with the PSM/forced pulse-width modulation (PWM) option, reduce the external device count and improve efficiency.

The ADP1878/ADP1879 operate over the −40°C to +125°C junction temperature range and are available in a 14-lead LFCSP_WD package.

Features

• Power input voltage range: 2.95 V to 20 V
• On-board bias regulator
• 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 (ADP1879 only)
• Resistor programmable current limit
• Power good with internal pull-up resistor
• Externally programmable soft start
• Thermal overload protection
• Short-circuit protection
• Standalone precision enable input
• Integrated bootstrap diode for high-side drive
• Starts into a precharged output
• Available in a 14-lead LFCSP_WD package

Remarks:1.Table 8,11. Recommended InductorsRefer page no.24,32.

2.Table 10. External Component ValuesRefer page no.31

Typical applications

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

More information

• Datasheet
• IC product information