- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄98002 > LTC1938IDD#TRPBF (LINEAR TECHNOLOGY CORP) 4 A SWITCHING REGULATOR, 3300 kHz SWITCHING FREQ-MAX, PDSO10 PDF資料下載
參數(shù)資料
| 型號(hào)： | LTC1938IDD#TRPBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 4 A SWITCHING REGULATOR, 3300 kHz SWITCHING FREQ-MAX, PDSO10 |
| 封裝： | 3 X 3 MM, LEAD FREE, PLASTIC, MO-229WEED-2, DFN-10 |
| 文件頁數(shù)： | 9/24頁 |
| 文件大?。?/td> | 272K |
| 代理商： | LTC1938IDD#TRPBF |
LT1938
17
1938f
Hot Plugging Safely
The small size, robustness and low impedance of ceramic
capacitors make them an attractive option for the input
bypass capacitor of LT1938 circuits. However, these capaci-
tors can cause problems if the LT1938 is plugged into a
live supply (see Linear Technology Application Note 88 for
a complete discussion). The low loss ceramic capacitor,
combined with stray inductance in series with the power
source, forms an under damped tank circuit, and the
voltage at the VIN pin of the LT1938 can ring to twice the
nominal input voltage, possibly exceeding the LT1938’s
rating and damaging the part. If the input supply is poorly
controlled or the user will be plugging the LT1938 into an
energized supply, the input network should be designed
to prevent this overshoot. Figure 9 shows the waveforms
that result when an LT1938 circuit is connected to a 24V
supply through six feet of 24-gauge twisted pair. The
rst plot is the response with a 4.7μF ceramic capacitor
at the input. The input voltage rings as high as 50V and
the input current peaks at 26A. A good solution is shown
in Figure 9b. A 0.7
Ω resistor is added in series with the
APPLICATIONS INFORMATION
Figure 8. A Good PCB Layout Ensures Proper, Low EMI Operation
VIAS TO LOCAL GROUND PLANE
VIAS TO VOUT
VIAS TO RUN/SS
VIAS TO PG
VIAS TO VIN
OUTLINE OF LOCAL
GROUND PLANE
1938 F08
L1
C2
RRT
RPG
RC
R2
R1
CC
VOUT
D1
C1
GND
input to eliminate the voltage overshoot (it also reduces
the peak input current). A 0.1μF capacitor improves high
frequency ltering. For high input voltages its impact on
efciency is minor, reducing efciency by 1.5 percent for
a 5V output at full load operating from 24V.
High Temperature Considerations
The PCB must provide heat sinking to keep the LT1938
cool. The Exposed Pad on the bottom of the package must
be soldered to a ground plane. This ground should be tied
to large copper layers below with thermal vias; these lay-
ers will spread the heat dissipated by the LT1938. Place
additional vias can reduce thermal resistance further. With
these steps, the thermal resistance from die (or junction)
to ambient can be reduced to
θJA = 35°C/W or less. With
100 LFPM airow, this resistance can fall by another 25%.
Further increases in airow will lead to lower thermal re-
sistance. Because of the large output current capability of
the LT1938, it is possible to dissipate enough heat to raise
the junction temperature beyond the absolute maximum of
125°C. When operating at high ambient temperatures, the
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC1955IUH#TR | 2-CHANNEL POWER SUPPLY SUPPORT CKT, PQCC32 |
| LTC1955IUH | 2-CHANNEL POWER SUPPLY SUPPORT CKT, PQCC32 |
| LTC2900-1CMS#TRPFB | 4-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO10 |
| LTC3125EDCB#TRPBF | SWITCHING REGULATOR, 1900 kHz SWITCHING FREQ-MAX, PDSO8 |
| LTC3125EDCB#PBF | SWITCHING REGULATOR, 1900 kHz SWITCHING FREQ-MAX, PDSO8 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC1949ES8 | 制造商:Linear Technology 功能描述: |
| LTC1955EUH | 功能描述:IC INTERFACE DL SMART CARD 32QFN RoHS:否 類別:集成電路 (IC) >> 接口 - 控制器 系列:- 標(biāo)準(zhǔn)包裝:2,450 系列:- 控制器類型:SPI 總線至 I²C 總線橋接 接口:I²C，串行，SPI 電源電壓:2.4 V ~ 3.6 V 電流 - 電源:11mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:24-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:24-HVQFN（4x4） 包裝:托盤 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名稱:935286452157SC18IS600IBSSC18IS600IBS-ND |
| LTC1955EUH#PBF | 功能描述:IC INTERFACE DL SMART CARD 32QFN RoHS:是 類別:集成電路 (IC) >> 接口 - 控制器 系列:- 標(biāo)準(zhǔn)包裝:2,450 系列:- 控制器類型:SPI 總線至 I²C 總線橋接 接口:I²C，串行，SPI 電源電壓:2.4 V ~ 3.6 V 電流 - 電源:11mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:24-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:24-HVQFN（4x4） 包裝:托盤 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名稱:935286452157SC18IS600IBSSC18IS600IBS-ND |
| LTC1955EUH#TR | 功能描述:IC SMART CARD INTERFC DUAL 32QFN RoHS:否 類別:集成電路 (IC) >> 接口 - 控制器 系列:- 標(biāo)準(zhǔn)包裝:2,450 系列:- 控制器類型:SPI 總線至 I²C 總線橋接 接口:I²C，串行，SPI 電源電壓:2.4 V ~ 3.6 V 電流 - 電源:11mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:24-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:24-HVQFN（4x4） 包裝:托盤 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名稱:935286452157SC18IS600IBSSC18IS600IBS-ND |
| LTC1955EUH#TRPBF | 功能描述:IC INTERFACE DL SMART CARD 32QFN RoHS:是 類別:集成電路 (IC) >> 接口 - 控制器 系列:- 標(biāo)準(zhǔn)包裝:2,450 系列:- 控制器類型:SPI 總線至 I²C 總線橋接 接口:I²C，串行，SPI 電源電壓:2.4 V ~ 3.6 V 電流 - 電源:11mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:24-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:24-HVQFN（4x4） 包裝:托盤 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名稱:935286452157SC18IS600IBSSC18IS600IBS-ND |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。