Date: 29/01/2012

Switching regulator and two LDOs in single chip for powering FPGAs

Analog Devices, Inc. has introduced ADP5041 and ADP5040 multi-output regulators. The regulators combine high-efficiency, 3-MHz, 1.2-A buck-type switching regulator and two 300-mA LDOs (low dropout regulators) in a small 20-lead LFCSP package. ADI says unlike discrete power solutions that require up to 14 components and 126 mm2 of board space, these regulators provide a more integrated circuit solution using only nine components and 50 mm2 of board space, to increase performance and reliability and lower system cost.

The ADP5041 and ADP5040 are suggested as ideal power management companions to mid-range FPGAs, microprocessor and DSP systems where core, IO and memory voltages are necessary. The ADP5041 regulator features on-chip watchdog timer and a ±1.5% accurate over temperature reset generator to monitor low voltage power supply rails. A wide range of ordering options also is available to address multiple reset and watchdog timings.

The ADP5041 has a special circuit that detects a three-state condition when applied to the watchdog refresh input at the WDI pin typically controlled by a processor/DSP output port. When the processor sets this port in three-state mode, the watchdog refresh timer is disabled, preventing a watchdog reset to the processor. As per ADI this feature is important when supporting processor/DSP sleep operation where the core is disabled and watchdog timer cannot be refreshed.

The ADP5040 and ADP5041 has switching regulators with up 96 percent buck power efficiency. For low-noise analog circuit applications, the LDOs maintain a power supply rejection greater than 60 dB for frequencies up to 10 kHz while operating with a low headroom voltage. The ADP5041 and ADP5040 also provide a three-rail system power supply (1.2-A buck regulator and two 300-mA LDOs) with adjustable output voltages, which allows output voltages to be easily set using an external resistor divider network. The 3-MHz buck regulator switching frequency allows small ceramic inductors to be used to further reduce solution size and cost.

ADP5041 andADP5040 Multi-output Regulator Key Features:
One 1.2-A buck regulator
Output voltage range = 0.8 V to 3.8 V
Current mode topology for excellent transient response
3-MHz operating frequency
Peak efficiency up to 96 percent
Regulator total accuracy: ±3 percent
Two 300-mA LDOs
Output voltage range = 0.8 V to 4.75 V
Low input supply voltage from 1.7 V to 5.5 V
Stable with 2.2-µF ceramic output capacitors
High PSRR = 60-dB up to 10 kHz
Low output noise = 60 µV rms typical output noise at 1.2 V
Low dropout voltage = 150-mV at 300-mA load

Product Availability Junction Temperature Range Price Each Per 1,000 Packaging
ADP5041 Now -40°C to 125°C $1.79 20-lead, 4 mm × 4 mm LFCSP package
ADP5040 Now -40°C to 125°C $1.39 20-lead, 4 mm × 4 mm LFCSP package