MTM006 Ultra-Small and High Efficiency Power Module  for Optical Communications

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Abstract

With the growth of giant data centers and huge amounts of information delivered through global networks, traditional electronic formats of data transmission can no longer keep up with the demand on speed and capacity, hence the opto-electronic communication technology emerges as a rising star to find more applications in data transmissions. The rapid advancement of opto-electronic technology drives the performance requirements of its core component, the optical module. This paper discusses the key characteristics of M3TEK's ultra-small, high efficiency power module for advanced optical communication modules, analyzes its technical advantages in packaging, efficiency, thermal management, transient responses, and provides an outlook to future development trends.

Requirements for power management system in optical modules

The power management system in the optical module is responsible for providing stable supplies for various devices in the optical module. The load switches, DC-DC converters and LDO’s are important parts of the power management system, and each of them serves different roles. The load switches provide protections to the downstream circuits. High efficiency DC-DC converters convert the input voltage into various voltages levels required by the system; LDOs, with its low power and low noise advantages, provide supplies for systems that require high accuracy or sensitivities.

Optical modules place stringent requirements on the power system, mainly in the following areas:

1. Package Height: Preferably less than 1.1mm. While 1.6mm is also acceptable, it needs to be placed on the upper side of the double-layer PCB, or needs special opening on the construction of the module.

2. Efficiency: Higher than 92% power efficiency. Sometimes high efficiency at light load is desired to meet the idle mode power consumption spec of the optical module.

3. Thermal Management：Heat generated by the power system contributes to the temperature rise of the optical module. The temperature level of the optical module is a very important operating spec. The wavelength and power level of optical devices are strongly dependent on their temperature, and big temperature fluctuations can lead to failure of data communications.

4. Transient Response：The faster the transient response, the better for the optical module. The transient response ripple voltage is desired to be as small as possible to ensure a stable supply.

Core features of the MTM006 power module

Based on the above requirements for optical module power management systems, M3TEK has developed an ultra-small, high efficiency step-down converter module MTM006. The MTM006 integrates a high performance step-down converter and the power inductor, supporting maximum continuous output current of 3A. It operates with an input voltage from 2.5V to 5.5V and provides output voltage range from 0.6V to as high as input level. MTM006 employs a proprietary Fast-PWM control scheme that simplifies the loop compensation and offers superior load transient response. The high gain error amplifier in its control loop ensures excellent load and line regulation.

MTM006N consumes extremely low 20µA quiescent current hence achieves superior light load efficiency with PFM mode. MTM006A, working in FPWM mode, provides the best transient response and low output ripple across full load range. For fault tolerant operation, MTM006 has cycle-by-cycle current limit protection and hiccup mode for short circuit or over-load condition.

The MTM006 is available in QFN2.5x3.5mm_18L package and ideal power solution for high performance optical modules.

1. Ultra-small package

The MTM006 is packaged in a QFN2.5x3.5mm_18L package with built-in synchronous step-down converter and inductor. Compared to traditional discrete inductor power converters, the MTM006 requires only one input capacitor, one output capacitor, and voltage divider resistors for setting the output. A complete set of power supply solutions can be realized in a very small footprint. Figure 1 shows the MTM006 package.

Fig.1 MTM006 Package

Fig.2a MTM006 Application Circuit

2. High Effectively

MTM006 is a synchronous step-down converter module with built-in 24mΩ HS switch, 16mΩ LS switch, and a 37mΩ DCR inductor. With compact PCB layout reduces PCB board routing power loss, and advanced packaging technology improves the thermal performance, the MTM006 power solution achieves a conversion efficiency as high as 96%.

The MTM006 has two different modes, MTM006N with PFM mode and MTM006A in FPWM mode. In light load condition, MTM006N works in PFM mode and cuts down its quiescent current to as low as 20uA to achieve excellent light load efficiency.