Power Electronics

Power Management ICs Optimized for 32-bit Processors

Embedded system designers using advanced processors, such as Motorola's MPC500, ColdFire 5200 and 5300, and MPC824x families, can now take advantage of new power management ICs to easily implement comprehensive power management functions. The MC33997, MC33998, and MC33394 power management ICs, based on Motorola's SmartMOS technology, control the processor's operating voltage or a complete block within a system.

Motorola's new power management IC family includes engine, transmission, and high-performance auto body applications; industrial and process control; and avionics systems. In networking applications, the devices combine with MPC824x or ColdFire integrated microprocessors to support system voltage needs.

The MC33394 is a multi-output power supply with a high-speed controller area network (CAN) transceiver. The IC's unique power sequencing simplifies power control of advanced processor architectures. This feature supplies each required voltage with the correct timing and level relative to the core voltage — a requirement for many new, deep submicron processors.

This IC incorporates a step-up/step-down switching pre-regulator, which operates over a 4V to 26.5V input range (transients up to 45V). Additional features include multiple LDO regulators with current limiting, adjustable low-voltage LDO with external pass transistor, and three sensor supplies protected against short-to-battery and short-to-ground. Other features include reset signals, Power On Reset, and Serial Peripheral Interface (SPI) for control and diagnostics.

The MC33997 and MC33998 are multiple output, medium-power supply ICs that operate from 5.5V to 40V inputs. They offer features similar to the MC33394, but with no CAN transceiver. Other differences include 5V (1400mA) output provided by a sensorless current mode step-down switching regulator with soft-start. In addition, a 3.3V output (for the MC33997) or 2.6V output (for the MC33998) is provided by an LDO using an external pass transistor. An additional 3.3V or 2.6V (10mA) output is for standby use. There are also two internally protected sensor supplies with low on-resistance LDMOS 5V (200mA, typical) outputs. Separate enable inputs provide main and sensor supply output control with reset and power-on reset delay.

Existing power management IC families include the MC33389, MC33889, and MC33989, which support the high-performance HCS12 16-bit processor architecture. The newest devices will also be applicable to multivoltage 8-bit and 16-bit processors that will begin to emerge.

These new power supply ICs are based on Motorola's SMARTMOS technology — a process that integrates high-density/high-speed logic with precision analog and high-voltage/high-current power circuitry. This enables a reduction of the number of system components by using ICs that combine analog, power, and logic functions on one chip, as well as increasing the tolerance to extreme environmental conditions. Also, as every processor requires power supply supervisory functions, SMARTMOS is an excellent IC technology to monitor system inputs and control of electrical loads.

The MC33394 comes in a 44-lead HSOP (heat sink small outline package) or a 44-lead QFN (quad flat no-lead) package. Samples of the MC33997 are available in a 24-lead SOICW (small outline IC wide) package, with production quantities available as of August 2002. Samples of the MC33998 are available in a 16-lead SOICW package, with production quantities expected in May 2003.

Motorola Analog Products Div., Tempe, Ariz. CIRCLE 349 on Reader Service Card

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