- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄377752 > LTC1539IGW (LINEAR TECHNOLOGY CORP) Dual High Efficiency, Low Noise, Synchronous Step-Down Switching Regulators PDF資料下載
參數(shù)資料
| 型號： | LTC1539IGW |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Dual High Efficiency, Low Noise, Synchronous Step-Down Switching Regulators |
| 中文描述： | 2 A SWITCHING CONTROLLER, 400 kHz SWITCHING FREQ-MAX, PDSO36 |
| 封裝： | 0.300 INCH, PLASTIC, SSOP-36 |
| 文件頁數(shù)： | 10/32頁 |
| 文件大?。?/td> | 451K |
| 代理商： | LTC1539IGW |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁當(dāng)前第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁
10
LTC 1538-AUX/LTC 1539
OPERATIO
Main Control Loop
U
The LTC1538-AUX/LTC1539 use a constant frequency,
current mode step-down architecture. During normal op-
eration, the top MOSFET is turned on each cycle when the
oscillator sets the RS latch and turned off when the main
current comparator I1 resets the RS latch. The peak
inductor current at which I1 resets the RS latch is con-
trolled by the voltage on the I
TH1
(I
TH2
) pin, which is the
output of each error amplifier (EA). The V
PROG1
pin,
described in the Pin Functions, allows the EA to receive a
selectively attenuated output feedback voltage V
FB1
from
the SENSE
–
1 pin while V
PROG2
and V
OSENSE2
allow EA to
receive an output feedback voltage V
FB2
from either inter-
nal or external resistive dividers on the second controller.
When the load current increases, it causes a slight de-
crease in V
FB
relative to the 1.19V reference, which in turn
causes the I
TH1
(I
TH2
) voltage to increase until the average
inductor current matches the new load current. After the
large top MOSFET has turned off, the bottom MOSFET is
turned on until either the inductor current starts to reverse,
as indicated by current comparator I2, or the beginning of
the next cycle.
The top MOSFET drivers are biased from floating boot
strap capacitor C
B
, which normally is recharged during
each Off cycle. When V
IN
decreases to a voltage close to
V
OUT
, however, the loop may enter dropout and attempt to
turn on the top MOSFET continuously. The dropout detec-
tor counts the number of oscillator cycles that the top
MOSFET remains on and periodically forces a brief off
period to allow C
B
to recharge.
The main control loop is shut down by pulling the RUN/
SS1 (RUN/SS2) pin low. Releasing RUN/SS1 (RUN/SS2)
allows an internal 3
μ
A current source to charge soft start
capacitor C
SS
. When C
SS
reaches 1.3V, the main control
loop is enabled with the I
TH1
(I
TH2
) voltage clamped at
approximately 30% of its maximum value. As C
SS
contin-
ues to charge, I
TH1
(I
TH2
) is gradually released allowing
normal operation to resume. When both RUN/SS1 and
RUN/SS2 are low, all LTC1538-AUX/LTC1539 functions
are shut down except for the 5V standby regulator, internal
reference and a comparator. Refer to the LTC1438/LTC1439
for applications which do not require a 5V standby regulator.
Comparator OV guards against transient overshoots
> 7.5% by turning off the top MOSFET and keeping it off
until the fault is removed.
Low Current Operation
Adaptive Power Mode allows the LTC1539 to automati-
cally change between two output stages sized for different
load currents. The TGL1 (TGL2) and BG1 (BG2) pins drive
large synchronous N-channel MOSFETs for operation at
high currents, while the TGS1 (TGS2) pin drives a much
smaller N-channel MOSFET used in conjunction with a
Schottky diode for operation at low currents. This allows
the loop to continue to operate at normal operating fre-
quency as the load current decreases without incurring the
large MOSFET gate charge losses. If the TGS1 (TGS2) pin
is left open, the loop defaults to Burst Mode operation in
which the large MOSFETs operate intermittently based on
load demand. Adaptive Power mode provides constant
frequency operation down to approximately 1% of rated
load current. This results in an order of magnitude reduc-
tion of load current before Burst Mode operation com-
mences. Without the small MOSFET (ie: no Adaptive
Power mode) the transition to Burst Mode operation is
approximately 10% of rated load current. The transition to
low current operation begins when comparator I2 detects
current reversal and turns off the bottom MOSFET. If the
voltage across R
SENSE
does not exceed the hysteresis of
I2 (approximately 20mV) for one full cycle, then on follow-
ing cycles the top drive is routed to the small MOSFET at
the TGS1 (TGS2) pin and the BG1 (BG2) pin is disabled.
This continues until an inductor current peak exceeds
20mV/R
SENSE
or the I
TH1
(I
TH2
) voltage exceeds 0.6V,
either of which causes drive to be returned to the TGL1
(TGL2) pin on the next cycle.
Two conditions can force continuous synchronous opera-
tion, even when the load current would otherwise dictate
low current operation. One is when the common mode
voltage of the SENSE
+
1 (SENSE
+
2) and SENSE
–
1
(SENSE
–
2) pins are below 1.4V, and the other is when the
SFB1 pin is below 1.19V. The latter condition is used to
assist in secondary winding regulation, as described in the
Applications Information section.
(Refer to Functional Diagram)
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC1538-AUX | Advanced LinEPIC Self-Calibrating (Self-Cal) Precision Single Operational Amplifier 8-SOIC |
| LTC1539 | Dual High Efficiency, Low Noise, Synchronous Step-Down Switching Regulators |
| LTC1538-AUXIG | ER 1C 1#4 SKT PLUG |
| LTC1538IG-AUX | DIODE ZENER SINGLE 1000mW 15Vz 50mA-Izt 0.05 1uA-Ir 11 PowerDI-123 3K/REEL |
| LTC1538CG-AUX | Dual High Efficiency, Low Noise, Synchronous Step-Down Switching Regulators |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC1539IGW#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 36-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX |
| LTC1539IGW#TR | 功能描述:IC REG CTRLR BUCK PWM CM 36-SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX |
| LTC1539IGW#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 36-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX |
| LTC1540CDD | 功能描述:IC COMP NANOPOWER W/REF 8DFN RoHS:否 類別:集成電路 (IC) >> 線性 - 比較器 系列:- 標(biāo)準(zhǔn)包裝:25 系列:- 類型:帶電壓基準(zhǔn) 元件數(shù):4 輸出類型:CMOS，開路漏極，TTL 電壓 - 電源，單路/雙路(±):2 V ~ 11 V，±1 V ~ 5.5 V 電壓 - 輸入偏移（最小值）:10mV @ 5V 電流 - 輸入偏壓（最小值）:- 電流 - 輸出（標(biāo)準(zhǔn)）:0.015mA @ 5V 電流 - 靜態(tài)（最大值）:8.5µA CMRR, PSRR（標(biāo)準(zhǔn)）:80dB CMRR，80dB PSRR 傳輸延遲（最大）:12µs 磁滯:50mV 工作溫度:0°C ~ 70°C 封裝/外殼:16-DIP（0.300"，7.62mm） 安裝類型:通孔 包裝:管件 |
| LTC1540CDD#PBF | 功能描述:IC COMP NANOPOWER W/REF 8DFN RoHS:是 類別:集成電路 (IC) >> 線性 - 比較器 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 類型:通用 元件數(shù):1 輸出類型:CMOS，開路集電極，TTL 電壓 - 電源，單路/雙路(±):2.7 V ~ 5.5 V 電壓 - 輸入偏移（最小值）:7mV @ 5V 電流 - 輸入偏壓（最小值）:0.25µA @ 5V 電流 - 輸出（標(biāo)準(zhǔn)）:84mA @ 5V 電流 - 靜態(tài)（最大值）:120µA CMRR, PSRR（標(biāo)準(zhǔn)）:- 傳輸延遲（最大）:600ns 磁滯:- 工作溫度:-40°C ~ 85°C 封裝/外殼:SC-74A，SOT-753 安裝類型:表面貼裝 包裝:剪切帶 (CT) 產(chǎn)品目錄頁面:1268 (CN2011-ZH PDF) 其它名稱:*LMV331M5*LMV331M5/NOPBLMV331M5CT |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。