LM2650
Synchronous Step-Down DC/DC Converter
Overview
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Parametrics
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Reliability
Features
Ultra high efficiencies (95% possible)
High efficiency over a 3A to milliamperes load range
Synchronous switching of internal NMOS power FETs
Wide input voltage range (4.5V to 18V)
Output voltage adjustable from 1.5V to 16V
Automatic low-power sleep mode
Logic-controlled micropower shutdown (IQSD
< 25 µA)
Frequency adjustable up to 300 kHz
Frequency synchronization with external signal
Programmable soft-start
Short-circuit current limiting
Thermal shutdown
Available in 24-lead Small-Outline package
Description
The LM2650 is a step-down DC/DC converter featuring high efficiency over a 3A to milliamperes load range. This feature makes the LM2650 an ideal fit in battery-powered applications that demand long battery life in both run and standby modes.
The LM2650 also features a logic-controlled shutdown mode in which it draws at most 25µA from the input power supply.
The LM2650 employs a fixed-frequency pulse-width modulation (PWM) and synchronous rectification to achieve very high efficiencies. In many applications, efficiencies reach 95%+ for loads around 1A and exceed 90% for moderate to heavy loads from 0.2A to 2A.
A low-power hysteretic or "sleep" mode keeps efficiencies high at light loads. The LM2650 enters and exits sleep mode automatically as the load crosses "sleep in" and "sleep out" thresholds. The LM2650 provides nodes for programming both thresholds via external resistors. A logic input allows the user to override the automatic sleep feature and keep the LM2650 in PWM mode regardless of the load level.
An optional soft-start feature limits current surges from the input power supply at start up and provides a simple means of sequencing multiple power supplies.
Applications
Notebook and palmtop personal computers
Portable data terminals
Modems
Portable Instruments
Global positioning devices (GPSs)
Battery-powered digital devices
Also Recommended
LM25576▲ 3A Integrated Switching Converter With 42V Max Input Voltage
LM2679▲ 5A 40V Integrated Buck Regulator
LM2853▲ 3A Integrated Synchronous Buck For Low Voltage Applications
LM3100▲ 36V 1.5A Integrated Synchronous Buck Regulator
LM5576▲ 3A Integrated Buck Regulator With 75V Input Capability
Parameters / Values LM2650 LM25576 LM2679 LM2853 LM3100 LM5576
Output Current 3000 mA
3000 mA
5000 mA
3000 mA
1500 mA
3000 mA
Input Min Voltage 4.5 Volt
6 Volt
15, 8 Volt
3 Volt
4.5 Volt
6 Volt
Input Max Voltage 18 Volt
42 Volt
40 Volt
5.5 Volt
36 Volt
75 Volt
Output Min 1.5 Volt
1.23 Volt
3.3, 1.23, 12, 5 Volt
1.8, 1, 2.5, 1.2, 0.8, 3.3, 3, 1.5 Volt
0.8 Volt
1.23 Volt
Output Max 16 Volt
40 Volt
3.3, 12, 37, 5 Volt
1.8, 1, 2.5, 1.2, 0.8, 3.3, 3, 1.5 Volt
7 Volt
70 Volt
Frequency Min 90 kHz
50 kHz
260 kHz
550 kHz
Undefined kHz
50 kHz
Frequency Max 300 kHz
1000 kHz
260 kHz
550 kHz
1000 kHz
500 kHz
Efficiency (peak) 95 %
91 %
84, 92, 82 %
95 %
86 %
88 %
Integrated Inductor No
No
No
PowerGood / Error Flag No
No
No
No
No
No
SoftStart Yes
Yes
Yes
Yes
Yes
Yes
Sync Pin Yes
Yes
No
No
No
Yes
Inverting No
Yes
No
No
Yes
Flyback No
No
No
No
No
No
RegType Switching Regulator
Switching Regulator
Switching Regulator
Switching Regulator
Switching Regulator
Switching Regulator
Temperature Min -40 deg C
-40 deg C
-40 deg C
-40 deg C
-40 deg C
-40 deg C
Temperature Max 125 deg C
125 deg C
125 deg C
125 deg C
125 deg C
125 deg C
Adjustable Output Yes
Yes
Yes, No
No
Yes
Yes
Adj Switch Frequency Yes
Yes
No
No
Yes
Yes
PWM Mode Current Mode Control
Current
Voltage with Vin Feedforward
Voltage Mode Control
Constant On-time
Current
Topology Synchronous Buck
Buck
Buck
Synchronous Buck
Synchronous Buck
Buck
Special Features Max. Iq at shutdown is 25uA over full temp. range
1.5% feedback voltage accuracy, emulated current mode
Programmable current limit, 2% output voltage accuracy, SIMPLE SWITCHER regulator
Internal compensation, low standby current
Vin feed forward and Current Injection compensation, SIMPLE SWITCHER synchronous regulator
1.5% feedback voltage accuracy, emulated current mode
Step-Down Yes
Yes
Yes
Yes
Yes
Yes
Multiple Output Capability No
No
No
No
No
No
Output Power Undefined Watt
Undefined Watt
Undefined Watt
Undefined Watt
Undefined Watt
Undefined Watt
Output Range 1.5V to16V
1.23V to 37V
12V, 1.23V to 37V, 3.3V, 5V
1.8, 1, 2.5, 1.2, 0.8, 3.3, 3, 1.5
0.8V to 7V
1.23V to 70V
Switching Frequency 90 kHz
1000 kHz
260 kHz
Undefined kHz
1000 kHz
500 kHz
Feedback Voltage Undefined Volt
Undefined Volt
Undefined Volt
On/Off Pin Yes
Yes
No
Yes
Yes
Yes
Regulator Family Undefined
SIMPLE SWITCHER
SIMPLE SWITCHER
SIMPLE SWITCHER
SIMPLE SWITCHER
SIMPLE SWITCHER
AEC Q-100 Automotive Grade Undefined
1
Undefined
Undefined
1
Synchronous Rectification Yes
No
No
Yes
Yes
No
Datasheets
Application Notes
Part Number(s) (NSID) Top View Availability Current Reported Stock Budgetary Pricing Pack Size
LM2650M-ADJ/NOPB LM2650M-ADJ
RoHS Status SOIC WIDE Full production Lead Time: 6 weeks
$3.93 each at 1K+ pcs rail of 30
LM2650MX-ADJ/NOPB LM2650MX-ADJ
RoHS Status SOIC WIDE Full production Lead Time: 6 weeks
$3.93 each at 1K+ pcs reel of 1000
All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html .
Moisture Sensitivity Level Data for LM2650 .
A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html .
National's certificate of product compliance for LM2650 is located at RoHS Status .
All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html .
Moisture Sensitivity Level Data for LM2650 .
A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html .
National's certificate of product compliance for LM2650 is located at RoHS Status .
CAD Symbols and Models
Models
Reliability Metrics
Part Number
Process
EFR Reject
EFR Sample Size
PPM
LTA Rejects
LTA Device Hours
FITS
MTTF (Hours)
LM2650M-ADJ LMDMOS 0 18295 0 0 2650000 2 751944735
LM2650MX-ADJ LMDMOS 0 18295 0 0 2650000 2 751944735
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 .
All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html .
Moisture Sensitivity Level Data for LM2650 .
A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html .
National's certificate of product compliance for LM2650 is located at RoHS Status .
[Information as of 9-Feb-2012]
Copyright © 2011 National Semiconductor Corporation