ADP3156

Features:

Active Voltage Positioning with Gain and Offset Adjustment
Optimal Compensation for Superior Load Transient Response
Fixed 1.5 V, 1.8 V and 2.5 V Output Versions
Dual N-Channel Synchronous Driver
On-Board Linear Regulator Controller
Total Output Accuracy 61% Over Temperature
High Efficiency, Current-Mode Operation
Short Circuit Protection
Overvoltage Protection Crowbar Protects Loads with No Additional External Components
Power Good Output
SO-16 Package


Application

Desktop Computer Supplies
ACPI-Compliant Power Systems
General Purpose DC-DC Converters


Pinout




Specifications

Input Supply Voltage (V_CC)  . . . . . . . . . . . . . . .0.3 V to +16 V
Shutdown Input Voltage  . . . . . . . . . . . . . . . .  0.3 V to +16 V
Operating Ambient Temperature Range  . . . . . .  0°C to +70°C
Junction Temperature Range  . . . . . . . . . . . . . . 0°C to +150°C
_JA  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .      90°C/W
Storage Temperature Range  . . . . . . . . . . .   65°C to +150°C
Lead Temperature (Soldering, 10 sec)  . . . . . . . . . .  .  +300°C


Description

The ADP3156 is a highly efficient synchronous buck switching regulator controller optimized for converting the 3.3 V or 5 V main supply into lower supply voltages required on the motherboards of Pentium® III and other high performance processor systems. The ADP3156 uses a current mode, constant off-time architecture to drive two external N-channel MOSFETs at a programmable switching frequency that can be optimized for size and efficiency. It also uses a unique supplemental regulation technique called active voltage positioning to enhance load transient performance. Active voltage positioning results in a
DC/DC converter that provides the best possible transient response using the minimum number of output capacitors and smallest footprint. Unlike voltage-mode and standard currentmode architectures, active voltage positioning adjusts the output voltage of ADP3156 as a function of the load current so that it is always optimally positioned for a system transient.

The ADP3156 provides accurate and reliable short circuit protection and adjustable current limiting. It also includes an integrated overvoltage crowbar function to protect the microprocessor from destruction in case the core supply exceeds the nominal programmed voltage by more than 15%.