Overview
The PM6686 is a dual step-down controller designed by STMicroelectronics to provide high-efficiency power conversion with a lossless current sensing technique. This controller is optimized for applications requiring multiple regulated output voltages, particularly in portable electronic devices. It features a constant on-time architecture, which ensures fast load transient response and nearly constant switching frequency operation. The PM6686 also incorporates pulse skipping at light loads to enhance efficiency and includes a minimum switching frequency of 33 kHz to avoid audio noise issues.
Key Specifications
| Parameter | Value | Description |
|---|---|---|
| Input Voltage Range | 5.5 V to 28 V | Operating input voltage range |
| Output Voltages | OUT1: 1.5 V / 5 V (fixed) or 0.7 V to 5.5 V (adjustable) OUT2: 1.05 V / 3.3 V (fixed) or 0.7 V to 2.5 V (adjustable) | Output voltage options with ±1.5% accuracy |
| Output Voltage Accuracy | ±1.5% | Accuracy over valley regulation |
| Switching Frequency | Selectable | Three different values of switching frequencies for the two switching sections |
| Minimum Switching Frequency in Pulse Skip Mode | 33 kHz | To avoid audio noise issues |
| Linear Regulator Output | 3.3 V / 5 V (fixed) or 0.7 V to 4.5 V (adjustable) | Up to 100 mA output current |
| Package | VFQFPN-32 (5x5 mm) | Package type and dimensions |
Key Features
- Lossless current sensing technique
- Constant on-time architecture for fast load transient response
- Pulse skipping at light loads to increase efficiency
- Selectable switching frequency to avoid audio noise issues
- Embedded voltage feed-forward for nearly constant switching frequency operation
- Soft-start and soft-stop capabilities
- Independent Power Good and EN signals
- Latched OVP and UVP protection
- Optional external charge pump monitoring
- Linear regulator with switchover function to source up to 200 mA
Applications
- Notebook computers
- Main power supply (3.3 V/5 V), chipset power supply (1.5 V/1.05 V), DDR1/2/3, and graphic cards
- PDAs, mobile devices, tablet PCs, or slates
- 3-4 cells Li+ battery powered devices
Q & A
- What is the input voltage range of the PM6686?
The input voltage range of the PM6686 is from 5.5 V to 28 V.
- What are the possible output voltages for OUT1 and OUT2?
OUT1 can be set to 1.5 V / 5 V (fixed) or 0.7 V to 5.5 V (adjustable), and OUT2 can be set to 1.05 V / 3.3 V (fixed) or 0.7 V to 2.5 V (adjustable).
- What is the accuracy of the output voltages?
The output voltages have an accuracy of ±1.5% over valley regulation.
- Can the switching frequency be adjusted?
- What is the minimum switching frequency in pulse skip mode?
The minimum switching frequency in pulse skip mode is 33 kHz to avoid audio noise issues.
- What are the features of the linear regulator?
The linear regulator can provide fixed outputs of 3.3 V / 5 V or an adjustable output from 0.7 V to 4.5 V, with up to 100 mA output current.
- What kind of protection does the PM6686 offer?
The PM6686 offers latched OVP (Overvoltage Protection) and UVP (Undervoltage Protection).
- Can the PM6686 monitor an external charge pump?
- What is the package type and dimensions of the PM6686?
The PM6686 comes in a VFQFPN-32 package with dimensions of 5x5 mm.
- What are some typical applications of the PM6686?
The PM6686 is typically used in notebook computers, PDAs, mobile devices, tablet PCs, and other 3-4 cells Li+ battery powered devices.
