LM3668 - 1A, High Efficiency Dual Mode Single Inductor Buck-Boost DC/DC Converter

LM3668

1A, High Efficiency Dual Mode Single Inductor Buck-Boost DC/DC Converter from the PowerWise® Family

Overview

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Reliability

Obsolete

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Features

• 45µA typical quiescent current

• For 2.8V/3.3V and 3.0/3.4V versions:
• - 1A maximum load current for V_IN = 2.8V to 5.5V
• - 800mA maximum load current for V_IN = 2.7V
• - 600mA maximum load current for V_IN = 2.5V

• For 4.5/5V
• - 1A maximum load current for V_IN = 3.9V to 5.5V
• - 800mA maximum load current for V_IN = 3.4V to 3.8V
• - 700mA maximum load current for V_IN = 3.0V to 3.3V
• - 600mA maximum load current for V_IN = 2.7V to 2.9V

• 2.2MHz PWM fixed switching frequency (typ.)

• Automatic PFM-PWM Mode or Forced PWM Mode

• Wide Input Voltage Range: 2.5V to 5.5V

• Internal synchronous rectification for high efficiency

• Internal soft start: 600µs Maximum start-up time after V_IN settled

• 0.01µA typical shutdown current

• Current overload and Thermal shutdown protection

• Frequency Sync Pin: 1.6MHz to 2.7MHz

Description
The LM3668 is a synchronous buck-boost DC-DC converter optimized for powering low voltage circuits from a Li-Ion battery and input voltage rails between 2.5V and 5.5V. It has the capability to support up to 1A output current over the output voltage range. The LM3668 regulates the output voltage over the complete input voltage range by automatically switching between buck or boost modes depending on the input voltage.

The LM3668 has 2 N-channel MOSFETS and 2 P-channel MOSFETS arranged in a topology that provides continuous operation through the buck and boost operating modes. There is a MODE pin that allows the user to choose between an intelligent automatic PFM-PWM mode operation and forced PWM operation. During PWM mode, a fixed-frequency 2.2MHz (typ.) is used. PWM mode drives load up to 1A. Hysteretic PFM mode extends the battery life through reduction of the quiescent current to 45µA (typ.) at light loads during system standby. Internal synchronous rectification provides high efficiency. In shutdown mode (Enable pin pulled low) the device turns off and reduces battery consumption to 0.01µA (typ.).

The LM3668 is available in a 12-pin LLP package. A high switching frequency of 2.2MHz (typ.) allows the use of tiny surface-mount components including a 2.2µH inductor, a 10µF input capacitor, and a 22µF output capacitor.

Applications

• Handset Peripherals

• MP3 players

• Pre-Regulation for linear regulators

• PDAs

• Portable Hard Disk Drives

• WiMax Modems

LM3668

2.50 <= V in Lower
V
<= V in Upper
V
<= 5.50

V out 2.80 <= V <= 3.30

I out A <= 1.60

Ambient Temperature °C <= 100

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LM3668

Typical Application *click for larger image

Block Diagram *click for larger image

Typical Performance click for larger image

Parameters Values

Switch Current 1, 1000 Amp

Output Min 3, 2.8 Volt

Output Max 3.3, 5 Volt

Output Range 2.8/3.3

Input Min Voltage 2.5 Volt

Input Max Voltage 5.5 Volt

Frequency Min 1600 kHz

Frequency Max 2700 kHz

Efficiency (peak) 93 %

Sync Pin Yes

Adj Switch Frequency No, Yes

On/Off Pin Yes

Error Flag No

SoftStart Yes

Special Features Buck-Boost, Aut

PWM Mode Auto PFM-PWM & Forced PWM

Topology Voltage Mode

RegType LDO, Switching Regulator

Adjustable Output No

Temperature Min -40 deg C

Temperature Max 85 deg C

PowerWise Yes

Datasheet
Title Size Date Other
Language

LM3668 1A, High Efficiency Dual Mode Single Inductor Buck-Boost DC/DC Converter 4770
Kbytes 24-Mar-09 日本語

Featured Application Notes
Title Size Date Other
Language

AN-1623: Application Note 1623 LM3668 Evaluation Board 394
Kbytes 24-Mar-09 日本語

More Application Notes
Title Size Date Other
Language

AN-1623: Application Note 1623 LM3668 Evaluation Board 394
Kbytes 24-Mar-09 日本語

Part Number(s)
(NSID)

Top View

Availability

Current Reported Stock

Budgetary Pricing

Standard Pack Size

LM3668SD-2833/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor	Region	Qty
AVNET-EM	Worldwide	1000
DIGIKEY	Worldwide	1797
FUTURE	Worldwide	1100

$2.25 each at 1K+ pcs

reel
of
1000

LM3668SD-3034/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	1619

$2.25 each at 1K+ pcs

reel
of
1000

LM3668SD-4550/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	1265

$2.25 each at 1K+ pcs

reel
of
1000

LM3668SDX-2833/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	0

$2.25 each at 1K+ pcs

reel
of
4500

LM3668SDX-3034/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	0

$2.25 each at 1K+ pcs

reel
of
4500

LM3668SDX-4550/NOPB

RoHS

Full production
Lead Time: 6 weeks

Distributor		Region	Qty
DIGIKEY		Worldwide	0

$2.25 each at 1K+ pcs

reel
of
4500

Obsolete Versions

Obsolete Part Alternate Part or Supplier Source Last Time Buy Date

LM3668SD-3.3
LM3668SD-2833

27 May 2009

LM3668SDX-3.3
LM3668SD-2833

27 May 2009

Part Number(s)
(NSID)

Description

Availability

Current Reported Stock

Budgetary Pricing

Standard Pack Size

LM3668SD-2833EV

LM3668SD-2833 Evaluation Board

Full production

Distributor		Region	Qty
DIGIKEY		Worldwide	0
NATIONAL		Worldwide	2

$75.00 each

Description:

The LM3668 is a synchronous buck-boost DC-DC converter optimized for powering low voltage circuits from a Li-Ion battery and input voltage rails between 2.5V and 5.5V. It has the capability to support up to 1A output current over the output voltage range. The LM3668 regulates the output voltage over the complete input voltage range by automatically switching between buck or boost modes depending on the input voltage.

The LM3668 evaluation board is a working demonstration of a synchronous buck-boost Dc-Dc converter. The application note contains information about the evaluation board. For more details and electrical characteristics about the converter operation, please refer to the datasheet.

Features:

45 µ A typical quiescent current
For 2.8V/3.3V and 3.0/3.4V versions:
     --1A maximum load current for V_IN = 2.8V to 5.5V
     --800mA maximum load current for V_IN = 2.7V
     --600mA maximum load current for V_IN = 2.5V
For 4.5/5V
     --1A maximum load current for V_IN = 3.9V to 5.5V
     --800mA maximum load current for V_IN = 3.4V to 3.8V
     --700mA maximum load current for V_IN = 3.0V to 3.3V
     --600mA maximum load current for V_IN = 2.7V to 2.9V
2.2MHz PWM fixed switching frequency (typ.)
Automatic PFM-PWM Mode or Forced PWM Mode
Wide Input Voltage Range: 2.5V to 5.5V
Internal synchronous rectification for high efficiency
Internal soft start: 600 µ s Maximum start-up time after V_IN settled.
0.01 µ A typical shutdown current
Current overload and Thermal shutdown protection
Frequency Sync Pin: 1.6MHz to 2.7MHz

Applications:

Handset Peripherals
MP3 players
Pre-regulation for linear regulators
PDAs
Portable Hard Disk Drives
WiMax Modems

Part Number(s)
(NSID)

Description

Availability

Current Reported Stock

Budgetary Pricing

Standard Pack Size

LM3668SD-3034EV

LM3668SD-3034 Evaluation Board

Full production

Distributor		Region	Qty
DIGIKEY		Worldwide	0
NATIONAL		Worldwide	13

$75.00 each

General Description:

Features:

45 µ A typical quiescent current
For 2.8V/3.3V and 3.0/3.4V versions:
  --1A maximum load current for V_IN = 2.8V to 5.5V
  --800mA maximum load current for V_IN = 2.7V
  --600mA maximum load current for V_IN = 2.5V
For 4.5/5V
  --1A maximum load current for VI_IN = 3.9V to 5.5V
  --800mA maximum load current for V_IN = 3.4V to 3.8V
  --700mA maximum load current for V_IN = 3.0V to 3.3V
  --600mA maximum load current for V_IN = 2.7V to 2.9V
2.2MHz PWM fixed switching frequency (typ.)
Automatic PFM-PWM Mode or Forced PWM Mode
Wide Input Voltage Range: 2.5V to 5.5V
Internal synchronous rectification for high efficiency
Internal soft start: 600 µ s Maximum start-up time after V_IN settled.
0.01 µ A typical shutdown current
Current overload and Thermal shutdown protection
Frequency Sync Pin: 1.6MHz to 2.7MHz

Applications:

Handset Peripherals
MP3 players
Pre-regulation for linear regulators
PDAs
Portable Hard Disk Drives
WiMax Modems

Part Number(s)
(NSID)

Description

Availability

Current Reported Stock

Budgetary Pricing

Standard Pack Size

LM3668SD-4550EV

LM3668SD-4550 Evaluation Board

Full production

Distributor		Region	Qty
DIGIKEY		Worldwide	0
NATIONAL		Worldwide	22

$75.00 each

Description:

Features:

45 µ A typical quiescent current
For 2.8V/3.3V and 3.0/3.4V versions:
  --1A maximum load current for V_IN = 2.8V to 5.5V
  --800mA maximum load current for V_IN = 2.7V
  --600mA maximum load current for V_IN = 2.5V
For 4.5/5V
  --1A maximum load current for VI_IN = 3.9V to 5.5V
  --800mA maximum load current for V_IN = 3.4V to 3.8V
  --700mA maximum load current for V_IN = 3.0V to 3.3V
  --600mA maximum load current for V_IN = 2.7V to 2.9V
2.2MHz PWM fixed switching frequency (typ.)
Automatic PFM-PWM Mode or Forced PWM Mode
Wide Input Voltage Range: 2.5V to 5.5V
Internal synchronous rectification for high efficiency
Internal soft start: 600 µ s Maximum start-up time after V_IN settled.
0.01 µ A typical shutdown current
Current overload and Thermal shutdown protection
Frequency Sync Pin: 1.6MHz to 2.7MHz

Applications:

Handset Peripherals
MP3 players
Pre-regulation for linear regulators
PDAs
Portable Hard Disk Drives
WiMax Modems

Part Number(s) (NSID)	Type	Pins	MSL Rating	Peak Reflow	RoHS	CAD Symbols	Models	Package Marking Format
LM3668SD-2833/NOPB	LLP	12	1	260	RoHS	N/A	N/A	ZXYTT S017B
LM3668SD-3034/NOPB	LLP	12	1	260	RoHS	N/A	N/A	ZXYTT S018B
LM3668SD-4550/NOPB	LLP	12	1	260	RoHS	N/A	N/A	ZXYTT S019B
LM3668SDX-2833/NOPB	LLP	12	1	260	RoHS	N/A	N/A	ZXYTT S017B
LM3668SDX-3034/NOPB	LLP	12	1	260	RoHS	N/A	N/A	ZXYTT S018B
LM3668SDX-4550/NOPB	LLP	12	1	260	RoHS	N/A	N/A	ZXYTT S019B

Design Tools
Title Size Date

Article - Enabling Multimedia in Next-Generation Handhelds

Article - Optimizing Power Consumption in the Mobile Multimedia Delivery Chain - Part One

Article - Optimizing Power Consumption in the Mobile Multimedia Delivery Chain - Part Two

Reliability Metrics

Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)

LM3668SD-2833 CMOS7 0 18406 0 0 1089000 4 309006723

LM3668SD-3034 CMOS7 0 18406 0 0 1089000 4 309006723

LM3668SD-4550 CMOS7 0 18406 0 0 1089000 4 309006723

LM3668SDX-2833 CMOS7 0 18406 0 0 1089000 4 309006723

LM3668SDX-3034 CMOS7 0 18406 0 0 1089000 4 309006723

LM3668SDX-4550 CMOS7 0 18406 0 0 1089000 4 309006723

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.

Obsolete Versions

Obsolete Part Alternate Part or Supplier Source Last Time Buy Date

LM3668SD-3.3
LM3668SD-2833

27 May 2009

LM3668SDX-3.3
LM3668SD-2833

27 May 2009

Power for Portable Applications (Boost, Buck-Boost, & Integrated)
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Power for Portable Applications (Boost, Buck-Boost, & Integrated)
Date: 01/15/08
Length: 0:4:25

[Information as of 21-Nov-2009]