概要

The controller is an integrated circuit realized in BCD5 (BiCMOS-DMOS, version 5) fabrication that provides complete control logic and protection for high performance step-down DC-DC and niPoL converters. It is designed to drive N-channel MOSFETs in a synchronous rectified buck topology. The output voltage of the converter can be precisely regulated down to 600 mV with a maximum tolerance of ±0.8 % and it is also possible to use an external reference from 0 V to 2.5 V.
The input voltage can range from 1.8 V to 14 V, while the supply voltage can range from 4.5 V to 14 V. High peak current gate drivers provide for fast switching to the external power section, and the output current can be in excess of 20 A. The PWM duty cycle can range from 0 % to 100 % with a minimum on-time (T_ON, _MIN) lower than 100 ns making possible conversions with very low duty cycle at high switching frequency. The device provides voltage-mode control that includes a selectable frequency oscillator (250 kHz or 500 kHz).
The error amplifier features a 10 MHz gain-bandwidth-product and 5 V/µs slew-rate that permits to realize high converter bandwidth for fast transient response. The device monitors the current by using the R_DS(on) of both the high-side and low-side MOSFET(s), eliminating the need for a current sensing resistor and guaranteeing an effective over-current-protection in all the application conditions. When necessary, two different current limit protections can be externally set through two external resistors.
During the soft-start phase a constant current protection is provided while after the soft-start the device enters in hiccup mode in case of over-current. During the soft-start, the sink mode capability is disabled in order to allow a proper start-up also in pre-biased output voltage conditions. After the soft-start the device can sink current. Other features are power good, master/slave synchronization (with 180° phase shift), over-voltage-protection, feed-back disconnection and thermal shutdown. The HTSSOP16 package allows the realization of really compact DC/DC converters.