SMB110 datasheet(3/34 Pages) SUMMIT

3 / 34 page

SMB110

Preliminary Information

Summit Microelectronics, Inc

2099 2.3 5/3/2005

The SMB110 is a fully programmable DC-DC controller

that monitors, margins, and cascade sequences. It has 5

voltage outputs, consisting of: two synchronous “buck”

step-down controllers, one “boost” step-up controller,

one “boost-buck” negative DC-DC controller, and one

LDO.

The SMB110 uses a fixed 800 kHz Pulse Width

Modulation (PWM) control circuit. A type three voltage

mode compensation network is used offering a cost

effective solution without compromising the transient

response. By utilizing external n and p–type MOSFET

transistors the efficiency and load current can be

customized to fit a wide array of system requirements.

The SMB110 integrates two buck outputs that are

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 less than the battery can

be produced without the need to change external

components.

In addition, the SMB110 integrates one boost output

capable of producing an output voltage greater than the

input voltage. The boost topology is asynchronous, using

a rectifying Schottky diode and eliminating the need for

an additional external MOSFET driver. An external p-

channel sequencing MOSFET’s accompanies the boost

channel in order to isolate the switching MOSFET from

the battery when disabled.

The SMB110 also contains one inverting buck-boost

output capable of producing a negative output voltage

less than or greater than, the input voltage. The buck

boost output is asynchronous and drives an external p-

channel MOSFET.

A Low DropOut linear regulator with fixed 3.3 volt output

provides a low current supply for “always on”

microcontrollers. The LDO has a special input supply

that is internally multiplexed between the LDO supply pin

and the battery. This ensures that the LDO will always

be active over the recommended operating voltages

(2.7V – 6.0V).

The SMB110 is 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 sequence position is guaranteed to

reach its programmed output voltage before the

channel(s) occupying the next sequence position initiate

their

respective

soft-start

sequence.

unique

programmable delay exists between each power on/off

sequence

position.

In addition

power

on/off

sequencing all supplies can be powered on/off

individually through an I

2C command or by assertion of

an 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. An

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 one of two output status pins

can be asserted. The current system status is always

accessible via internal registers containing the status of

all four channels.

The SMB110 possesses an Undervoltage Lockout

(UVLO) circuit to ensure the SMB110 will not power up

until the battery 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 SMB110 provides margining control over all of its

output voltages. Through an I

2C command, all outputs

can be margined to any voltage setting within the

nominal output voltage rage. Margining creates three

pre-programmed settings that each channel can be set

to via an I

2C command. Margining is ideal when used

with the boost channel configured as an LED driver

where margining provides three brightness settings.

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 SMB110 are stored in

non-volatile registers and are easily accessed and

modified over an industry standard I

2C serial bus. For

fastest prototype development times Summit offers an

evaluation card and a Graphical User Interface (GUI).

GENERAL DESCRIPTION

SMB110 датащи(PDF) 3 Page - Summit Microelectronics, Inc.

SMB110 датащи(HTML) 3 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 33 34

датащи скачать

ссылки URL