Datasheet Linear Technology LTC1909-8

Manufacturer	Linear Technology
Series	LTC1909-8

Wide Operating Range, No RSENSE Step-Down DC/DC Controller with SMBus Programming

Datasheets

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PDF, 659 Kb, File uploaded: Sep 20, 2017

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Packaging

	LTC1909-8EG#PBF	LTC1909-8EG#TRPBF
N	1	2
Package	SSOP-28 Package Outline Drawing	SSOP-28 Package Outline Drawing
Package Code	G	G
Package Index	05-08-1640 (G28)	05-08-1640 (G28)
Pin Count	28	28

Parametrics

Parameters / Models	LTC1909-8EG#PBF	LTC1909-8EG#TRPBF
Demo Boards	DC475A	DC475A
Export Control	no	no
Features	VID, Active Voltage Positioning, Resistor Set Frequency, Power Good	VID, Active Voltage Positioning, Resistor Set Frequency, Power Good
Frequency, kHz	200	200
Integrated Inductor	no	no
Ishutdown, µA	15	15
Isupply, mA	0.9	0.9
Max Phases	2	2
Monolithic	no	no
Number of Outputs	1	1
Operating Temperature Range, °C	0 to 85	0 to 85
Output Current, A	25	25
Polyphase	no	no
Switch Current, A	25	25
Synchronous	yes	yes
Topology	Buck	Buck
Vin Max, V	36	36
Vin Min, V	4	4
Vout Max, V	3.5	3.5
Vout Min, V	1.3	1.3

Eco Plan

	LTC1909-8EG#PBF	LTC1909-8EG#TRPBF
RoHS	Compliant	Compliant

Design Notes

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Active Voltage Positioning Reduces Output Capacitors &mdash Design Solutions 10
PDF, 130 Kb, File published: Nov 1, 1999
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Design Solutions 10
November 1999
Active Voltage Positioning Reduces Output Capacitors
by Robert Sheehan
INTRODUCTION
Power supply performance, especially transient response,
is key to meeting todayвЂ™s demands for low voltage, high
current microprocessor power. In an effort to minimize
the voltage deviation during a load step, a technique that
has recently been coined вЂњactive voltage positioningвЂќ is
generating substantial interest and gaining popularity in
the portable computer market. The benefits include lower
peak-to-peak output voltage deviation for a given load
step, without having to increase the output filter capacitance. Alternatively, the output filter capacitance can be
reduced while maintaining the same peak-to-peak transient response.
BASIC PRINCIPLE
The term вЂњactive voltage positioningвЂќ (AVP) refers to
setting the power supply output voltage at a point that is
dependent on the load current. At minimum load, the
output voltage is set to a slightly higher than nominal level.
At full load, the output voltage is set to a slightly lower than
nominal level. Effectively, the DC load regulation is
degraded, but the load transient voltage deviation will be …
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Microprocessor Core Supply Voltage Set by I2C Bus Without VID Lines &mdash DN279
PDF, 75 Kb, File published: Mar 1, 2002
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advertisement Microprocessor Core Supply Voltage Set by I2C Bus
without VID Lines вЂ“ Design Note 279
Mark Gurries
Introduction
Many modern CPUs run at two different clock speeds,
where each speed requires a different core operating
voltage to assure optimum performance. These voltages
are documented in the manufacturerвЂ™s VID (voltage
identiп¬Ѓcation) section of the CPU speciп¬Ѓcation. Some
new DC/DC converters (the LTCВ®1909, for example) have
built-in VID control that supports dual programmable
output voltages, but many existing converters do not.
The LTC1699 is a precision 2-state resistive divider that
uses a simple SMBus interface to allow VID control on
non-VID-enabled DC/DC converters. No dedicated VID
lines are required.
How it Works
DC/DC converters maintain consistent output voltage
by comparing the output voltage, through an accurate
voltage divider, against an internal reference and adjusting the output to compensate for differences. The
LTC1699 is a 2-state resistive divider that replaces the
п¬Ѓxed voltage divider in the feedback circuit, thus allowing the circuit to support two different voltage outputs.
It is speciп¬Ѓcally designed to work with DC/DC PWM …

Model Line

Series: LTC1909-8 (2)

LTC1909-8EG#PBF LTC1909-8EG#TRPBF

Manufacturer's Classification

Power Management > Switching Regulator > Digitally Programmable Regulators