SMB117 datasheet(2/32 Pages) SUMMIT

2 / 32 page

SMB113A/B/SMB117/A

Preliminary Information

Summit Microelectronics, Inc.

2111 2.4 6/24/2008

The SMB113A/B and SMB117/A are fully programmable

DC-DC controllers that incorporate power delivery and

advanced power monitoring and control functionality.

The devices integrate four synchronous “buck” step-

down controllers in a space saving package.

The SMB113A uses a fixed 800kHz whereas the

SMB113B uses a fixed 1MHz, the SMB117 a fixed

400kHz and the SMB117A a fixed 250kHz Pulse Width

Modulation (PWM) control circuit. A type-three voltage

mode compensation network is used offering a cost

effective

solution

without

compromising

transient

response performance. By utilizing external N- and P–

type MOSFET transistors the efficiency and load current

level can be customized to fit a wide array of system

requirements.

The SMB113A/B and SMB117/A contain four buck

outputs capable of producing an output voltage less than

the input voltage. Each buck output voltage is set by an

internal resistor divider and a programmable voltage

reference. The integrated resistor divider eliminates the

cost and space necessary for external components and

has several programmable values.

Through the

programmability of the reference and the resistor divider,

practically any output voltage smaller than the battery

can be produced without the need to change external

components.

The SMB113A/B and SMB117/A are capable of power-

on/off cascade sequencing where each channel can be

assigned one of four unique sequence positions. During

sequencing each channel in a given sequencing position

is guaranteed to reach its programmed output voltage

before the channel(s) occupying the next sequence

position initiate their respective soft-start sequence. A

unique programmable delay exists between each power

on/off sequence position. In addition to power on/off

sequencing all supplies can be powered on/off

individually through an I

2C command or by assertion of

the enable pin.

Each output voltage is monitored for under-voltage and

over-voltage (UV/OV) conditions, using a comparator-

based circuit where the output voltage is compared

against an internal programmable reference.

additional feature of the output voltage monitoring is a

programmable glitch filter capable of digitally filtering a

transient OV/UV fault condition from a true system error.

When a fault is detected for a period in excess of the

glitch filter, all supplies may be sequenced down or

immediately disabled and an output status pin can be

asserted.

The current system status is always

accessible via internal registers containing the status of

all four channels.

The SMB113A/B and SMB117/A also possess an

Under-voltage Lockout (UVLO) circuit to ensure the

devices will not power up until the input voltage has

reached a safe operating voltage. The UVLO function

exhibits hysteresis, ensuring that noise or a brown out

voltage on the supply rail does not inadvertently lead to

a system failure.

The SMB113A/B and SMB117/A provide dynamic

voltage management over all of their output voltages.

Through an I

2C command, all output voltage levels can

be increased or decreased to a pre-programmed level.

In addition, each output is slew rate limited by soft-start

circuitry that is user-programmable and requires no

external capacitors.

All programmable settings on the SMB113A/B and the

SMB117/A are stored in non-volatile registers and are

easily accessed and modified over an industry standard

2C serial bus. For fastest prototype development times

Summit offers an evaluation card and a Graphical User

Interface (GUI).

GENERAL DESCRIPTION

SMB117 数据表(PDF) 2 Page - Summit Microelectronics, Inc.

SMB117 数据表(HTML) 2 Page - Summit Microelectronics, Inc.

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

数据表下载