- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄44992 > LTC3618IFE#PBF (LINEAR TECHNOLOGY CORP) 8 A DUAL SWITCHING CONTROLLER, 2700 kHz SWITCHING FREQ-MAX, PDSO24 PDF資料下載
參數(shù)資料
| 型號： | LTC3618IFE#PBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 8 A DUAL SWITCHING CONTROLLER, 2700 kHz SWITCHING FREQ-MAX, PDSO24 |
| 封裝： | 4.40 MM, LEAD FREE, PLASTIC, TSSOP-24 |
| 文件頁數(shù)： | 9/24頁 |
| 文件大小： | 603K |
| 代理商： | LTC3618IFE#PBF |
LTC3618
17
3618f
Output Voltage Programming
The output voltage of VDDQ is set by external resistive
dividers. For example, VDDQ can be set according to the
following equation:
VDDQ 0.6V 1
R1
R2
The resistive divider allows pin VFB1 to sense a fraction
of the output voltage as shown in Figure 3.
Pulse-Skipping Mode
VDDQ pulse-skipping mode, which is a compromise
between low output voltage ripple and efciency, can be
implemented by connecting the MODE/SYNC pin to SVIN.
In this condition, the peak inductor current is limited by
the minimum on-time of the current comparator. The low-
est output voltage ripple is achieved while still operating
discontinuously. During very light output loads, pulse-
skipping allows only a few switching cycles to skip while
maintaining the output voltage in regulation.
Internal and External Compensation
The regulator loop response can be checked by looking at
the load current transient response. Switching regulators
take several cycles to respond to a step in DC load current.
When a load step occurs, like the one shown in Figure 5,
VOUT shifts by an amount equal to ΔILOAD ESR, where
ESR is the effective series resistance of COUT. ΔILOAD
also begins to charge or discharge COUT, generating the
feedback error signal that forces the regulator to adapt
to the current change and return VOUT to its steady-state
value. During this recovery time, VOUT can be monitored
for excessive overshoot or ringing, which would indicate
a stability problem. The availability of the ITH pin allows
the transient response to be optimized over a wide range
of output capacitance.
The ITH1 external components (15.8k and 470pF) shown
in Figure 3 will provide an adequate compensation as
well as a starting point for most applications. The values
can be modied slightly to optimize transient response
once the nal PCB layout is complete and the particular
output capacitor type and value have been determined.
The output capacitors need to be selected because the
various types and values determine the loop gain and
phase. The gain of the loop will be increased by increas-
ing RC and the bandwidth of the loop will be increased
by decreasing CC. If RC is increased by the same factor
that CC is decreased, the zero frequency will be kept the
same, thereby keeping the phase shift the same in the
most critical frequency range of the feedback loop. The
output voltage settling behavior is related to the stabil-
ity of the closed-loop system. The external compensa-
tion, forced continuous operation circuit in the Typical
Applications section uses faster compensation to improve
load step response.
A second, more severe transient is caused by switching
in loads with large (>1μF) supply bypass capacitors. The
discharged bypass capacitors are effectively put in parallel
with COUT, causing a rapid drop in VOUT. No regulator can
alter its delivery of current quickly enough to prevent this
sudden step change in output voltage if the load switch
resistance is low and it is driven quickly. More output
capacitance may be required depending on the duty cycle
and load step requirements.
If the ITH pin is tied to SVIN, the internal compensation
is selected.
APPLICATIONS INFORMATION
Figure 5. Load Step Transient in FCM with
External Compensation
IL
1A/DIV
VOUT
200mV/DIV
3618 F05
VIN = 3.3V
VOUT = 1.8V
ILOAD = 600mA TO 2A
COMPENSATION AND OUTPUT
CAPACITOR VALUES OF FIGURE 3
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC3618EFE#TRPBF | 8 A DUAL SWITCHING CONTROLLER, 2700 kHz SWITCHING FREQ-MAX, PDSO24 |
| LTC3620EDC#PBF | SWITCHING REGULATOR, 50 kHz SWITCHING FREQ-MAX, PDSO8 |
| LTC3620EDC#TRMPBF | SWITCHING REGULATOR, 50 kHz SWITCHING FREQ-MAX, PDSO8 |
| LTC3620EDC-1#PBF | SWITCHING REGULATOR, 50 kHz SWITCHING FREQ-MAX, PDSO8 |
| LTC3620EDC-1#TRPBF | SWITCHING REGULATOR, 50 kHz SWITCHING FREQ-MAX, PDSO8 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC3618IUF#PBF | 功能描述:IC REG DUAL SYNC 3A BUCK 24QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標(biāo)準(zhǔn)包裝:43 系列:- 應(yīng)用:控制器，Intel VR11 輸入電壓:5 V ~ 12 V 輸出數(shù):1 輸出電壓:0.5 V ~ 1.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:48-QFN（7x7） 包裝:管件 |
| LTC3618IUF#TRPBF | 功能描述:IC REG DUAL SYNC 3A BUCK 24QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標(biāo)準(zhǔn)包裝:43 系列:- 應(yīng)用:控制器，Intel VR11 輸入電壓:5 V ~ 12 V 輸出數(shù):1 輸出電壓:0.5 V ~ 1.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:48-QFN（7x7） 包裝:管件 |
| LTC3619BEDD#PBF | 功能描述:IC REG BUCK SYNC ADJ DL 10DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:250 系列:- 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V 輸入電壓:2.05 V ~ 6 V PWM 型:電壓模式 頻率 - 開關(guān):2MHz 電流 - 輸出:500mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:6-UFDFN 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:6-SON（1.45x1） 產(chǎn)品目錄頁面:1032 (CN2011-ZH PDF) 其它名稱:296-25628-2 |
| LTC3619BEDD#PBF | 制造商:Linear Technology 功能描述:IC SYNC STEP-DOWN DC/DC CONVERTER DFN-10 |
| LTC3619BEDD#TRPBF | 功能描述:IC REG BUCK SYNC ADJ DL 10DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:升壓（升壓） 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式，混合 頻率 - 開關(guān):600kHz 電流 - 輸出:500mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-SOIC |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。