Datasheet
Package Availability, Models, Samples & Pricing
General Description
The LM5642 series consists of two current mode synchronous buck regulator controllers operating 180° out of phase with each
other at a normal switching frequency of 200kHz for the LM5642 and at 375kHz for the LM5642X.
Out of phase operation reduces the input RMS ripple current, thereby significantly reducing the required input capacitance.
The switching frequency can be synchronized to an external clock between 150kHz and 250kHz for the LM5642 and between 200
kHz and 500 kHz for the LM5642X. The two switching regulator outputs can also be paralleled to operate as a dual-phase, single
output regulator.
The output of each channel can be independently adjusted from 1.3V to 90% of Vin. An internal 5V rail is also available externally
for driving bootstrap circuitry.
Current-mode feedback control assures excellent line and load regulation and wide loop bandwidth for excellent response to
fast load transients. Current is sensed across either the Vds of the top FET or across an external current-sense resistor
connected in series with the drain of the top FET.
The LM5642 features analog soft-start circuitry that is independent of the output load and output capacitance making the soft-start
behavior more predictable and controllable than traditional soft-start circuits.
Over-voltage protection is available for both outputs. A UV-Delay pin is also available to allow delayed shut off time for
the IC during an output under-voltage event.
Reliability Metrics
| Part Number |
Process |
EFR Reject |
EFR Sample Size |
PPM |
LTA Rejects |
LTA Device Hours |
FITS |
MTTF (Hours) |
|
LM5642MH | ABCD150 | 0 | 31520 | 0 | 0 | 3739000 | 1 | 1060951459
|
|
LM5642MHX | ABCD150 | 0 | 31520 | 0 | 0 | 3739000 | 1 | 1060951459
|
|
LM5642MTC | ABCD150 | 0 | 31520 | 0 | 0 | 3739000 | 1 | 1060951459
|
|
LM5642MTCX | ABCD150 | 0 | 31520 | 0 | 0 | 3739000 | 1 | 1060951459
|
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 |
 |
|
|
| Power Reference Design Library |
0 Kbytes |
28-Mar-2006 |
View |
|
|
| Reducing Buck Converter Input Capacitance through Multi-Phasing and Clock Synchronization |
|
|
View |
|
|
| Mathcad Design Tools |
|
|
View |
|
|
Application Notes
| Title | Size in Kbytes |
Date |
|
| AN-1292: Application Note 1292 LM5642 Evaluation Board |
2111 Kbytes |
2-Sep-03 |
Download |
[Information as of 3-Jul-2009]
| 
RoHS Compliance Information
