LM3691 - High Accuracy, Miniature 1A, Step-Down DC-DC Converter for Portable Applications

LM3691

High Accuracy, Miniature 1A, Step-Down DC-DC Converter for Portable Applications from the PowerWise® Family

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Features

• V_OUT = 0.75V to 3.3V

• ±1% DC output voltage precision

• 2.3 ≤ V_IN ≤ 5.5V

• 4 MHz switching frequency

• 64 μA (typ.) quiescent current in ECO mode

• 1A maximum load capability

• Automatic ECO/PWM mode switching

• Mode Pin to select ECO/Forced PWM mode

• 1 μH inductor, 4.7 μF input capacitor (0603(1608) case size) and 4.7 μF output capacitor (0603(1608) case size)

• Current overload and thermal shutdown protections

• Only three tiny surface-mount external components required (solution size less than 15 mm 2)

Description
The LM3691 step-down DC-DC converter is optimized for powering ultra-low voltage circuits from a single Li-Ion cell or 3 cell NiMH/NiCd batteries. It provides up to 1A load current, over an input voltage range from 2.3V to 5.5V. There are several different fixed voltage output options available.

LM3691 has a mode-control pin that allows the user to select Forced PWM mode or ECO mode that changes modes between gated PWM mode and PWM automatically depending on the load. In ECO, LM3691 offers superior efficiency and very low I_q under light load conditions. ECO mode extends the battery life through reduction of the quiescent current during light load conditions and system standby.

The LM3691 is available in a 6–bump micro SMD package. Only three external surface-mount components, a 1 μH inductor, a 4.7 μF input capacitor and a 4.7 μF output capacitor, are required.

Applications

• Mobile Phones

• Hand-Held Radios

• MP3 players

• Portable Hard Disk Drives

revised typ application diagram

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LM3691

Typical Application *click for larger image

revised typ application diagram

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Typical Performance *click for larger image

Parameters Values

Output Current 1000 mA

Input Min Voltage 2.3 Volt

Input Max Voltage 5.5 Volt

Output Min 0.75 Volt

Output Max 1.8 Volt

Frequency Min 4000 kHz

Frequency Max 4000 kHz

Efficiency (peak) 95 %

On/Off Pin Yes

Error Flag No

SoftStart Yes

Sync Pin No

Inverting No

Flyback No

RegType Switching Regulator

Temperature Min -30 deg C

Temperature Max 85 deg C

Adjustable Output No

Adj Switch Frequency No

PWM Mode Voltage

Topology Synchronous Buck

Special Features Pin-selectable PWM/ECO mode, Typ. Iq in shutdown is 0.03uA, 1% output accuracy, only 3external components

Step-Down Yes

Multiple Output Capability No

Output Range 0.75V to 1.8V

Switching Frequency 4000 kHz

Feedback Voltage Undefined Volt

Regulator Family Undefined

Automotive No

PowerWise Yes

Synchronous Rectification Yes

Datasheet
Title Size Date Other
Language

LM3691 High Accuracy, Miniature 1A, Step-Down DC-DC Converter for Portable Applications 1897
Kbytes 20-Jan-09

Featured Application Notes
Title Size Date Other
Language

AN-1772: Application Note 1772 LM3691 Evaluation Board 567
Kbytes 14-May-08

More Application Notes
Title Size Date Other
Language

AN-87: Application Note 87 Comparing the High Speed Comparators 249
Kbytes 1-Oct-02

AN-1772: Application Note 1772 LM3691 Evaluation Board 567
Kbytes 14-May-08

AN-271: Application Note 271 Applying the New CMOS MICRO-DAC 230
Kbytes 4-Oct-04 日本語

AN-294: Application Note 294 Special Sample and Hold Techniques 233
Kbytes 4-Oct-04

Part Number(s)
(NSID)

Top View

Availability

Current Reported Stock

Budgetary Pricing

Standard Pack Size

LM3691TL-0.75/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	496

$2.00 each at 1K+ pcs

reel
of
250

LM3691TL-1.2/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	880
FUTURE		Worldwide	500

$2.00 each at 1K+ pcs

reel
of
250

LM3691TL-1.5/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	500
FUTURE		Worldwide	250

$2.00 each at 1K+ pcs

reel
of
250

LM3691TL-1.8/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor	Region	Qty
ARROW	Worldwide	250
AVNET-EM	Worldwide	250
DIGIKEY	Worldwide	168
FUTURE	Worldwide	250

$2.00 each at 1K+ pcs

reel
of
250

LM3691TL-2.5/NOPB

RoHS

Full production
Lead Time: 12 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	697

$2.00 each at 1K+ pcs

reel
of
250

LM3691TLX-0.75/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	0

$2.00 each at 1K+ pcs

reel
of
3000

LM3691TLX-1.2/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	0

$2.00 each at 1K+ pcs

reel
of
3000

LM3691TLX-1.5/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	0

$2.00 each at 1K+ pcs

reel
of
3000

LM3691TLX-1.8/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	0

$2.00 each at 1K+ pcs

reel
of
3000

LM3691TLX-2.5/NOPB

RoHS

Full production
Lead Time: 12 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	0

$2.00 each at 1K+ pcs

reel
of
3000

Part Number(s)
(NSID)

Description

Availability

Current Reported Stock

Budgetary Pricing

Standard Pack Size

LM3691TL-1.2EV

LM3691TL-1.2 Evaluation Board

Full production

Distributor		Region	Qty
DIGIKEY		Worldwide	0
NATIONAL		Worldwide	35

$92.00 each

Description:

The LM3691 step-down DC-DC converter is optimized for powering ultra-low voltage circuits from a single Li-Ion cell or 3 cell NiMH/NiCd batteries. It provides up to 1A load current, over an input voltage range from 2.3V to 5.5V. There are several different fixed voltage output options available.

The LM3691 evaluation board is a working demonstration of a step down DC-DC converter. This application note contains information about the evaluation board. For further information on buck converter topology, device electrical characteristics, and component selection, please refer to the datasheet.

Features:

V_OUT = 0.75V to 1.8V
± 1% DC output voltage precision
2.3 ≤ V_IN ≤ 5.5V
4 MHz switching frequency
64 µ A (typ.) quiescent current in ECO mode
1A maximum load capability
Automatic ECO/PWM mode switching
Mode Pin to select ECO/Forced PWM mode
1 µ H inductor, 4.7 µ F input capacitor (0603(1608) case size) and 4.7 µ F output capacitor (0603(1608) case size)
Current overload and thermal shutdown protections
Only three tiny surface-mount external components required (solution size less than 15 mm²)

Applications:

Mobile Phones
Hand-Held Radios
MP3 players
Portable Hard Disk Drives

Part Number(s)
(NSID)

Description

Availability

Current Reported Stock

Budgetary Pricing

Standard Pack Size

LM3691TL-1.8EV

LM3691TL-1.8 Evaluation Board

Full production

Distributor		Region	Qty
DIGIKEY		Worldwide	0
NATIONAL		Worldwide	37

$92.00 each

Description:

Features:

V_OUT = 0.75V to 1.8V
± 1% DC output voltage precision
2.3 ≤ V_IN ≤ 5.5V
4 MHz switching frequency
64 µ A (typ.) quiescent current in ECO mode
1A maximum load capability
Automatic ECO/PWM mode switching
Mode Pin to select ECO/Forced PWM mode
1 µ H inductor, 4.7 µ F input capacitor (0603(1608) case size) and 4.7 µ F output capacitor (0603(1608) case size)
Current overload and thermal shutdown protections
Only three tiny surface-mount external components required (solution size less than 15 mm²)

Applications:

Mobile Phones
Hand-Held Radios
MP3 players
Portable Hard Disk Drives

Part Number(s) (NSID)	Type	Pins	MSL Rating	Peak Reflow	RoHS	CAD Symbols	Models	Package Marking Format
LM3691TL-0.75/NOPB	MICRO SMD	6	1	260	RoHS	N/A	N/A	XV I V
LM3691TL-1.2/NOPB	MICRO SMD	6	1	260	RoHS	N/A	N/A	XV I X
LM3691TL-1.5/NOPB	MICRO SMD	6	1	260	RoHS	N/A	N/A	XV I Y
LM3691TL-1.8/NOPB	MICRO SMD	6	1	260	RoHS	N/A	N/A	XV I Z
LM3691TL-2.5/NOPB	MICRO SMD	6	1	260	RoHS	N/A	N/A	XV I 8
LM3691TLX-0.75/NOPB	MICRO SMD	6	1	260	RoHS	N/A	N/A	XV I V
LM3691TLX-1.2/NOPB	MICRO SMD	6	1	260	RoHS	N/A	N/A	XV I X
LM3691TLX-1.5/NOPB	MICRO SMD	6	1	260	RoHS	N/A	N/A	XV I Y
LM3691TLX-1.8/NOPB	MICRO SMD	6	1	260	RoHS	N/A	N/A	XV I Z
LM3691TLX-2.5/NOPB	MICRO SMD	6	1	260	RoHS	N/A	N/A	XV I 8

[Information as of 21-Nov-2009]