Datasheet.kr   

AN-SY8105 PDF 데이터시트 ( Data , Function )

부품번호 AN-SY8105 기능
기능 Synchronous Step Down Regulator
제조업체 Silergy
로고 Silergy 로고 


이 페이지 하단에 미리보기 및 AN-SY8105 다운로드 (pdf 파일) 링크가 있습니다.




전체 10 페이지

No Preview Available !

AN-SY8105 데이터시트, 핀배열, 회로
Applications Note:AN_SY8105
High Efficiency, 500kHz, 5A, 18V Input
Synchronous Step Down Regulator
General Description
The SY8105 is a high efficiency 500 kHz synchronous
step-down DC-DC converter capable of delivering
5.0A current. The SY8105 operates over a wide input
voltage range from 4.5V to 18V and integrates main
switch and synchronous switch with very low RDS(ON)
to minimize the conduction loss.
Low output voltage ripple and small external inductor
and capacitor sizes are achieved with 500 kHz
switching frequency. It adopts the instant PWM
architecture to achieve fast transient responses for high
step down applications
Ordering Information
SY8105 (□□)
Temperature Code
Package Code
Optional Spec Code
Ordering Number Package type Note
SY8105ADC
TSOT23-6
--
Features
low RDS(ON) for internal switches (top/bottom):
40mΩ/26mΩ
4.5-18V input voltage range
5.0A output current capability
500 kHz switching frequency
Instant PWM architecture to achieve fast transient
responses.
Internal softstart limits the inrush current
Cycle-by-cycle peak current limitation
1.5% 0.6V reference
TSOT23-6 package
Applications
Set Top Box
Portable TV
Access Point Router
DSL Modem
LCD TV
Typical Applications
Figure 1. Schematic Diagram
100
90
80
70
60
50
40
30
20
10
0
0.001
Efficiency vs. Load Current
VIN=5V,VOUT=3.3V
VIN=12V,VOUT=3.3V
VIN=16V,VOUT=3.3V
0.01
0.1
1
Load Current (A)
10
Figure 2. Schematic Diagram
AN_SY8105 Rev. 0.9 Silergy Corp. Confidential- Prepared for Customer Use Only
1




AN-SY8105 pdf, 반도체, 판매, 대치품
AN_SY8105
Electrical Characteristics
(VIN = 12V, VOUT = 1.2V, L = 2.2uH, COUT = 47uF, TA = 25°C, IOUT = 1A unless otherwise specified)
Parameter
Input Voltage Range
Quiescent Current
Shutdown Current
Feedback Reference
Voltage
FB Input Current
Top FET RON
Bottom FET RON
TOP FET Peak Current
Limit
Bottom FET Valley
Current Limit
EN Rising Threshold
EN Falling Threshold
Input UVLO Threshold
UVLO Hysteresis
Min ON Time
Min OFF Time
Switching Frequency
Thermal Shutdown
Temperature
Thermal Shutdown
Hysteresis
Symbol
VIN
IQ
ISHDN
VREF
IFB
RDS(ON)1
RDS(ON)2
ILIM,TOP
ILIM,BOTTOM
VENH
VENL
VUVLO
VHYS
Test Conditions
IOUT=0, VFB=VREF*105%
EN=0
VFB=3.3V
TSD
THYS
Min
4.5
0.591
Typ
100
5
0.6
-50
40
20
5.0
1.5
0.3
80
160
500
150
15
Max
18
10
0.609
Unit
V
µA
µA
V
50 nA
m
mΩ
10 A
A
V
0.4 V
4.5 V
V
ns
ns
kHz
°C
°C
Note 1: Stresses beyond the “Absolute Maximum Ratings” may cause permanent damage to the device. These are
stress ratings only. Functional operation of the device at these or any other conditions beyond those indicated in the
operational sections of the specification is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
Note 2: θ JA is measured in the natural convection at TA = 25°C on a two-layer Silergy Evaluation Board..
Note 3: The device is not guaranteed to function outside its operating conditions
AN_SY8105 Rev. 0.9 Silergy Corp. Confidential- Prepared for Customer Use Only
4

4페이지










AN-SY8105 전자부품, 판매, 대치품
AN_SY8105
Operation
SY8105 is a synchronous buck regulator IC that integrates
the PWM control, top and bottom switches on the same die to
minimize the switching transition loss and conduction loss.
With ultra low Rds(on) power switches and proprietary PWM
control, this regulator IC can achieve the high efficiency and
fast transient response. The high switching frequency allows
using of small profile inductor and capacitor and the highest
switch frequency simultaneously to minimize the external
inductor and capacitor size, and thus achieving the minimum
solution footprint.
Applications Information
Because of the high integration in the SY8105 IC, the
application circuit based on this regulator IC is rather
simple. Only input capacitor CIN, output capacitor COUT,
output inductor L and feedback resistors (R1 and R2)
need to be selected for the targeted applications
specifications.
Feedback resistor dividers R1 and R2:
Choose R1 and R2 to program the proper output voltage.
To minimize the power consumption under light loads,
it is desirable to choose large resistance values for both
R1 and R2. A value of between 10kΩ and 1MΩ is
highly recommended for both resistors. If Vout is 3.3V,
R1=100k is chosen, then using following equation, R2
can be calculated to be 22.1k:
VOUT
R
2
=
0.6V
V
OUT
0.6V
R
1
.
R1
FB
GND
R2
Input capacitor CIN:
The ripple current through input capacitor is calculated
as
I = I CIN _ RMS
OUT
D(1D) .
To minimize the potential noise problem, place a
typical X5R or better grade ceramic capacitor really
close to the IN and GND pins. Care should be taken to
minimize the loop area formed by CIN, and IN/GND
pins. For most applications, a 10uF ceramic capacitor
in parallel with 100nF 0603 size ceramic capacitor are
recommended. And place the 100nF/0603 capacitor
close to IC to attenuate high frequency noise.
Output capacitor COUT:
The output capacitor is selected to handle the output
ripple noise requirements. Both steady state ripple and
transient requirements must be taken into consideration
when selecting this capacitor. For the best performance,
it is recommended to use X5R or better grade ceramic
capacitor greater than 47uF capacitance.
Output inductor L:
There are several considerations in choosing this
inductor.
1) Choose the inductance to provide the desired
ripple current. It is suggested to choose the ripple
current to be about 40% of the maximum output
current. The inductance is calculated as:
L = VOUT (1 VOUT /VIN,MAX )
FSW × IOUT,MAX × 40%
where Fsw is the switching frequency and IOUT,MAX is
the maximum load current.
The SY8105 regulator IC is quite tolerant of different
ripple current amplitude. Consequently, the final choice
of inductance can be slightly off the calculation value
without significantly impacting the performance.
2) The saturation current rating of the inductor must
be selected to be greater than the peak inductor
current under full load conditions.
ISAT, MIN > IOUT, MAX + VOUT(1-VOUT/VIN,MAX)
2 FSW L
3) The DCR of the inductor and the core loss at the
switching frequency must be low enough to
achieve the desired efficiency requirement. It is
desirable to choose an inductor with DCR<20mΩ
to achieve a good overall efficiency.
Soft-start
The SY8105 has a built-in soft-start to control the rise
rate of the output voltage and limit the input current
surge during IC start-up. The typical soft-start time is
800us.
Enable Operation
Pulling the EN pin low (<0.4V) will shut down the
device. During shutdown mode, the SY8105
shutdown current drops to lower than 5uA, Driving the
EN pin high (>1.5V) will turn on the IC again.
AN_SY8105 Rev. 0.9 Silergy Corp. Confidential- Prepared for Customer Use Only
7

7페이지


구       성총 10 페이지
다운로드[ AN-SY8105.PDF 데이터시트 ]


 
구매 문의
일반 IC 문의 : 샘플 및 소량 구매
-----------------------------------------------------------------------

전력 반도체 판매 ( IGBT, TR 모듈, SCR, 다이오드 모듈 )

상호 : 아이지 인터내셔날

사이트 방문 : [ 홈페이지 ] [ 블로그 1 ] [ 블로그 2 ]


 

관련 데이터시트

부품번호상세설명 및 기능제조사
AN-SY8105

Synchronous Step Down Regulator

Silergy
Silergy

DataSheet.kr    |   2020   |  연락처   |  링크모음   |   검색  |   사이트맵