- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄224114 > LTC1435ACG#TRPBF (LINEAR TECHNOLOGY CORP) High Efficiency Low Noise Synchronous Step-Down Switching Regulator PDF資料下載
參數(shù)資料
| 型號： | LTC1435ACG#TRPBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | High Efficiency Low Noise Synchronous Step-Down Switching Regulator |
| 中文描述： | 2 A SWITCHING CONTROLLER, 138 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封裝： | PLASTIC, SSOP-16 |
| 文件頁數(shù)： | 6/20頁 |
| 文件大小： | 355K |
| 代理商： | LTC1435ACG#TRPBF |
14
LTC1435A
APPLICATIONS INFORMATION
WU
U
By powering EXTVCCfromanoutput-derivedsource,the
additional VIN current resulting from the driver and
control currents will be scaled by a factor of
Duty Cycle/Efficiency. For example, in a 20V to 5V ap-
plication, 10mA of INTVCC current results in approxi-
mately 3mA of VIN current. This reduces the midcurrent
loss from 10% or more (if the driver was powered di-
rectly from VIN) to only a few percent.
3. I2R losses are predicted from the DC resistances of the
MOSFET, inductor and current shunt. In continuous
mode the average output current flows through L and
RSENSE, but is “chopped” between the topside main
MOSFET and the synchronous MOSFET. If the two
MOSFETs have approximately the same RDS(ON), then
the resistance of one MOSFET can simply be summed
with the resistances of L and RSENSE to obtain I2R
losses. For example, if each RDS(ON) = 0.05,
RL = 0.15, and RSENSE = 0.05, then the total resis-
tance is 0.25
. This results in losses ranging from 3%
to 10% as the output current increases from 0.5A to
2A. I2R losses cause the efficiency to drop at high output
currents.
4. Transition losses apply only to the topside MOSFET(s),
and only when operating at high input voltages (typically
20V or greater). Transition losses can be estimated from:
Transition Loss = 2.5 (VIN)1.85(IMAX)(CRSS)(f)
Other losses, including CIN and COUT ESR dissipative
losses, Schottky conduction losses during dead-time,
and inductor core losses, generally account for less than
2% total additional loss.
Checking Transient Response
The regulator loop response can be checked by looking at
the load transient response. Switching regulators take sev-
eral cycles to respond to a step in DC (resistive) load cur-
rent. When a load step occurs, VOUT immediately shifts by
an amount equal to (
ILOAD)(ESR), where ESR is the ef-
fective series resistance of COUT. ILOAD also begins to
charge or discharge COUTwhichgeneratesafeedbackerror
signal. The regulator loop then acts to return VOUT to its
steady-state value. During this recovery time VOUT can be
monitored for overshoot or ringing, which would indicate
a stability problem. The ITH external components shown in
the Figure 1 circuit will provide adequate compensation for
most applications.
A second, more severe transient is caused by switching in
loads with large (>1
F) supply bypass capacitors. The
discharged bypass capacitors are effectively put in parallel
with COUT, causing a rapid drop in VOUT. No regulator can
deliver enough current to prevent this problem if the load
switch resistance is low and it is driven quickly. The only
solution is to limit the rise time of the switch drive so that
the load rise time is limited to approximately (25)(CLOAD).
Thus a 10
F capacitor would require a 250s rise time,
limiting the charging current to about 200mA.
Automotive Considerations:
Plugging into the Cigarette Lighter
As battery-powered devices go mobile, there is a natural
interest in plugging into the cigarette lighter in order to
conserve or even recharge battery packs during operation.
But before you connect, be advised: you are plugging into
the supply from hell. The main battery line in an automo-
bile is the source of a number of nasty potential transients,
including load dump, reverse battery and double battery.
Load dump is the result of a loose battery cable. When the
cable breaks connection, the field collapse in the alternator
can cause a positive spike as high as 60V which takes several
hundred milliseconds to decay. Reverse battery is just what
it says, while double battery is a consequence of tow truck
operators finding that a 24V jump start cranks cold engines
faster than 12V.
The network shown in Figure 9 is the most straightforward
approach to protect a DC/DC converter from the ravages
of an automotive battery line. The series diode prevents
current from flowing during reverse battery, while the
transient suppressor clamps the input voltage during load
dump. Note that the transient suppressor should not
Figure 9. Automotive Application Protection
1435A F09
50A IPK RATING
LTC1435A
TRANSIENT VOLTAGE
SUPPRESSOR
GENERAL INSTRUMENT
1.5KA24A
VIN
12V
相關PDF資料 |
PDF描述 |
|---|---|
| LTC1435ACS#PBF | High Efficiency Low Noise Synchronous Step-Down Switching Regulator |
| LTC1435ACS#TRPBF | High Efficiency Low Noise Synchronous Step-Down Switching Regulator |
| LTC1435AIG#PBF | High Efficiency Low Noise Synchronous Step-Down Switching Regulator |
| LTC1435AIS#PBF | High Efficiency Low Noise Synchronous Step-Down Switching Regulator |
| LTC1435CG#PBF | High Efficiency Low Noise Synchronous Step-Down Switching Regulator |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LTC1435ACS | 功能描述:IC REG CTRLR BUCK PWM CM 16-SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝: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 |
| LTC1435ACS#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 16-SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 特色產品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標準包裝:1 系列:PowerWise® PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.5 V ~ 18 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:-5°C ~ 125°C 封裝/外殼:32-WFQFN 裸露焊盤 包裝:Digi-Reel® 產品目錄頁面:1303 (CN2011-ZH PDF) 其它名稱:LM3754SQDKR |
| LTC1435ACS#TR | 功能描述:IC REG CTRLR BUCK PWM CM 16-SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝: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 |
| LTC1435ACS#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 16-SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝: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 |
| LTC1435ACSPBF | 制造商:Linear Technology 功能描述:Step down switching regulator,LTC1435CS |
發(fā)布緊急采購，3分鐘左右您將得到回復。