LM34919 - Ultra Small 40V, 600 mA Constant On-Time Buck Switching Regulator

LM34919 - Ultra Small 40V, 600 mA Constant On-Time Buck Switching Regulator from the PowerWise® Family

Datasheet	Packaging	Samples & Pricing	Eval. Boards	Reliability	Design Tools	Application Notes	Knowledge Base

Features

•	Integrated N-Channel buck switch
•	Integrated start-up regulator
•	Input Voltage Range: 8V to 40V
•	No loop compensation required
•	Ultra-Fast transient response
•	Operating frequency remains constant with load current and input voltage
•	Maximum switching frequency: 2.0 MHz
•	Maximum Duty Cycle Limited During Start-Up
•	Adjustable output voltage
•	Valley Current Limit At 0.64A
•	Precision internal reference
•	Low bias current
•	Highly efficient operation
•	Thermal shutdown

General Description

The LM34919 Step Down Switching Regulator features all of the functions needed to implement a low cost, efficient, buck bias regulator capable of supplying 0.6A to the load. More...

Typical Application

*click for larger image

Parameters Values

Output Current 600 mA

Input Min Voltage 8 Volt

Input Max Voltage 40 Volt

Output Min 2.5 Volt

Output Max 35 Volt

Frequency Min Undefined kHz

Frequency Max 1600 kHz

Efficiency (peak) 90 %

On/Off Pin Yes

Error Flag No

SoftStart Yes

Sync Pin No

Inverting Yes

Flyback No

RegType Switching Regulator

Temperature Min -40 deg C

Temperature Max 125 deg C

Adjustable Output Yes

Adj Switch Frequency Yes

PWM Mode Constant on-time

Topology Buck

Special Features No compensation req'd; ultra fast transient response

Step-Down Yes

Multiple Output Capability No

Output Power Undefined Watt

Output Voltage Undefined Volt

Output Range 2.5V to 35V

Feedback Voltage 2.5 Volt

Regulator Family Undefined

Automotive Yes

PowerWise Yes

Synchronous Rectification No

Typical Performance

*click for larger image

Additional Resources

Design Tools

Application Notes

Block Diagram

*click for larger image

Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LM34919 Ultra Small 40V, 600 mA Constant On-Time Buck Switching Regulator	377 Kbytes	2-Jun-08	Download

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Package Availability, Models, Samples & Pricing

Part Number

Package

Factory Lead Time

Models

Samples &
Electronic
Orders

Budgetary Pricing

Std
Pack
Size

Package
Marking
Format

Type

Pins

Spec.

MSL
Rating

Peak
Reflow

RoHS
Report

CAD
Symbols

Weeks

Qty

$US each

LM34919EVAL

Evaluation Board for the LM34919

Full production

N/A

$45.00

8 weeks

N/A

LM34919ATL

MICRO SMD

NOPB

260

RoHS

N/A

Preliminary

N/A

CALL

reel
of
N/A

XYTT
I SRYA

N/A

LM34919ATLX

MICRO SMD

NOPB

260

RoHS

N/A

Preliminary

N/A

CALL

reel
of
N/A

XYTT
I SRYA

N/A

LM34919TL

MICRO SMD

NOPB

260

RoHS

N/A

Full production

N/A

1K+

$1.05

reel
of
250

XYTT
I SRYB

6 weeks

N/A

LM34919TLX

MICRO SMD

NOPB

260

RoHS

N/A

Full production

N/A

1K+

$1.05

reel
of
3000

XYTT
I SRYB

6 weeks

N/A

General Description

The LM34919 Step Down Switching Regulator features all of the functions needed to implement a low cost, efficient, buck bias regulator capable of supplying 0.6A to the load. This buck regulator contains an N-Channel Buck Switch, and is available in a micro SMD package. The constant on-time feedback regulation scheme requires no loop compensation, results in fast load transient response, and simplifies circuit implementation. The operating frequency remains constant with line and load variations due to the inverse relationship between the input voltage and the on-time. The valley current limit results in a smooth transition from constant voltage to constant current mode when current limit is detected, reducing the frequency and output voltage, without the use of foldback. Additional features include: VCC under-voltage lockout, thermal shutdown, gate drive under-voltage lockout, and maximum duty cycle limiter.

Reliability Metrics

Part Number	Process	EFR Sample Size	LTA Device Hours	FITS	MTTF (Hours)
LM34919ATL	ABCD150	34175	4234000	1	1201409060
LM34919ATLX	ABCD150	34175	4234000	1	1201409060
LM34919TL	ABCD150	34175	4234000	1	1201409060
LM34919TLX	ABCD150	34175	4234000	1	1201409060

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.

Design Tools

Title	Size in Kbytes	Date
LM34919 Quick Start Calculator	365 Kbytes	3-Aug-2009	View

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Application Notes

Title	Size in Kbytes	Date
AN-1650: Application Note 1650 LM34919 Evaluation Board	338 Kbytes	8-Jun-07	Download
AN-1650 (Chinese): Application Note 1650 LM34919 Evaluation Board	366 Kbytes

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More Application Notes

Title	Size in Kbytes	Date
AN-1349: Application Note 1349 LM34910 Evaluation Board	562 Kbytes	18-Nov-04	Download
AN-1549: Application Note 1549 LM34914 Evaluation Board	319 Kbytes	17-Mar-07	Download
AN-1601: Application Note 1601 LM34917A Evaluation Board	1142 Kbytes	10-Apr-08	Download

If you have trouble printing or viewing PDF file(s), see Printing Problems.

[Information as of 7-Nov-2009]