Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.COM

X  

Preview PDF Download HTML

CS5165A Datasheet(PDF) 14 Page - ON Semiconductor

Part No. CS5165A
Description  5−Bit Synchronous CPU Buck Controller
Download  18 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  ONSEMI [ON Semiconductor]
Direct Link  http://www.onsemi.com
Logo ONSEMI - ON Semiconductor

CS5165A Datasheet(HTML) 14 Page - ON Semiconductor

Back Button CS5165A Datasheet HTML 10Page - ON Semiconductor CS5165A Datasheet HTML 11Page - ON Semiconductor CS5165A Datasheet HTML 12Page - ON Semiconductor CS5165A Datasheet HTML 13Page - ON Semiconductor CS5165A Datasheet HTML 14Page - ON Semiconductor CS5165A Datasheet HTML 15Page - ON Semiconductor CS5165A Datasheet HTML 16Page - ON Semiconductor CS5165A Datasheet HTML 17Page - ON Semiconductor CS5165A Datasheet HTML 18Page - ON Semiconductor  
Zoom Inzoom in Zoom Outzoom out
 14 / 18 page
background image
CS5165A
http://onsemi.com
14
Figure 27. Normal Operation Showing the Guaranteed
Non−Overlap Time Between the High and Low−Side
MOSFET Gate Drives, ILOAD = 14 A
Trace 1 = GATE(H) (5.0 V/div.)
Trace 2 = GATE(L) (5.0 V/div.)
@ 2.2 V
The CS5165A provides adaptive control of the external
NFET conduction times by guaranteeing a typical 65 ns
non−overlap between the upper and lower MOSFET gate drive
pulses. This feature eliminates the potentially catastrophic
effect of “shoot−through current”, a condition during which
both FETs conduct causing them to overheat, self−destruct, and
possibly inflict irreversible damage to the processor.
The most important aspect of FET performance is RDSON,
which effects regulator efficiency and FET thermal
management requirements.
The power dissipated by the MOSFETs may be estimated as
follows:
Switching MOSFET:
Power
+ ILOAD2
RDSON
duty cycle
Synchronous MOSFET:
Power
+ ILOAD2
RDSON
(1
* duty cycle)
Duty Cycle =
VOUT ) (ILOAD
RDSON OF SYNCH FET)
VIN)(ILOAD
RDSON OF SYNCH FET)
* (ILOAD
RDSON OF SWITCH FET)
Off Time Capacitor (COFF)
The COFF timing capacitor sets the regulator off time:
TOFF + COFF
4848.5
The preceding equations for duty cycle can also be used
to calculate the regulator switching frequency and select the
COFF timing capacitor:
COFF +
Perioid
(1
* duty cycle)
4848.5
where:
Period
+
1
switching frequency
Schottky Diode for Synchronous FET
For synchronous operation, a Schottky diode may be placed
in parallel with the synchronous FET to conduct the inductor
current upon turn off of the switching FET to improve
efficiency. The CS5165A reference circuit does not use this
device due to it’s excellent design. Instead, the body diode of
the synchronous FET is utilized to reduce cost and conducts the
inductor current. For a design operating at 200 kHz or so, the
low non−overlap time combined with Schottky forward
recovery time may make the benefits of this device not worth
the additional expense. The power dissipation in the
synchronous MOSFET due to body diode conduction can be
estimated by the following equation:
Power
+ VBD
ILOAD
conduction time
switching frequency
Where VBD = the forward drop of the MOSFET body
diode. For the CS5165A demonstration board:
Power
+ 1.6 V
14.2 A
100 ns
200 kHz
+ 0.45 W
This is only 1.1% of the 40 W being delivered to the load.
“Droop” Resistor for Adaptive Voltage Positioning
Adaptive voltage positioning is used to help keep the output
voltage within specification during load transients. To
implement adaptive voltage positioning a “Droop Resistor”
must be connected between the output inductor and output
capacitors and load. This resistor carries the full load current
and should be chosen so that both DC and AC tolerance limits
are met. An embedded PC trace resistor has the distinct
advantage of near zero cost implementation. However, this
droop resistor can vary due to three reasons: 1) the sheet
resistivity variation causes the thickness of the PCB layer to
vary. 2) the mismatch of L/W, and 3) temperature variation.
1. Sheet Resistivity for one ounce copper, the thickness
variation typically 1.15 mil to 1.35 mil. Therefore the
error due to sheet resistivity is:
1.35
* 1.15
1.25
+ 16%
2. Mismatch due to L/W. The variation in L/W is
governed by variations due to the PCB manufacturing
process that affect the geometry and the power
dissipation capability of the droop resistor. The error
due to L/W mismatch is typically 1.0%.
3. Thermal Considerations. Due to I2
× R power losses
the surface temperature of the droop resistor will
increase causing the resistance to increase. Also, the
ambient temperature variation will contribute to the
increase of the resistance, according to the formula:
R
+ R20[1 ) a20(T * 20)]
where:
R20 = resistance at 20°C
a + 0.00393
°C
T = operating temperature
R = desired droop resistor value
For temperature T = 50
°C, the % R change = 12%


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18 


Datasheet Download

Go To PDF Page

Related Electronics Part Number

Part No.DescriptionHtml ViewManufacturer
CS5159 CPU 5−Bit Synchronous Buck Controller 1  2  3  4  5  More ON Semiconductor
CS5160 CPU 5−Bit Synchronous Buck Controller 1  2  3  4  5  More ON Semiconductor
CS5161 CPU 5−Bit Synchronous Buck Controller 1  2  3  4  5  More ON Semiconductor
Z16C01 CPU CENTRAL PROCESSING UNIT 1  2  3  4  5  More Zilog, Inc.
IS61SF25616 256K x 16 256K x 18 SYNCHRONOUS FLOW-THROUGH STATIC RAM 1  2  3  4  5  More Integrated Silicon Solution, Inc
IS61SP6464 64K x 64 SYNCHRONOUS PIPELINE STATIC RAM 1  2  3  4  5  More Integrated Silicon Solution, Inc
MT9LSDT872 SYNCHRONOUS DRAM MODULE 1  2  3  4  5  More Micron Technology
AP3842 High Performance Current Mode PWM Controller 1  2  3  4  5  More Anachip Corp
BI3101A DUAL RWM CCFL CONTROLLER 1  2  3  4  5  More List of Unclassifed Manufacturers
M306V5ME-XXXSP SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER and ON-SCREEN DISPLAY CONTROLLER 1  2  3  4  5  More Mitsubishi Electric Semiconductor

Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn