- 您现在的位置：买卖IC网 > PDF目录69007 > LTC3406AES5#TRM (LINEAR TECHNOLOGY CORP) 1.3 A SWITCHING REGULATOR, 1800 kHz SWITCHING FREQ-MAX, PDSO5 PDF资料下载
参数资料
| 型号： | LTC3406AES5#TRM |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 1.3 A SWITCHING REGULATOR, 1800 kHz SWITCHING FREQ-MAX, PDSO5 |
| 封装： | 1 MM HEIGHT, LEAD FREE, PLASTIC, MO-193, TSOT-23, 5 PIN |
| 文件页数： | 3/16页 |
| 文件大小： | 265K |
| 代理商： | LTC3406AES5#TRM |
LTC3406A
11
3406af
The junction temperature, TJ, is given by:
TJ = TA + TR
where TA is the ambient temperature.
As an example, consider the LTC3406A in dropout at
an input voltage of 2.7V, a load current of 600mA and
an ambient temperature of 70°C. From the typical per-
formance graph of switch resistance, the RDS(ON) of the
P-channel switch at 70°C is approximately 0.27Ω. There-
fore, power dissipated by the part is:
PD = ILOAD2 RDS(ON) = 97.2mW
For the SOT-23 package, the θJA is 250°C/ W. Thus, the
junction temperature of the regulator is:
TJ = 70°C + (0.0972)(250) = 94.3°C
which is below the maximum junction temperature of
125°C.
Notethatathighersupplyvoltages,thejunctiontemperature
is lower due to reduced switch resistance (RDS(ON)).
Checking Transient Response
The regulator loop response can be checked by looking
at the load transient response. Switching regulators take
several cycles to respond to a step in load current. When
a load step occurs, VOUT immediately shifts by an amount
equal to (ΔILOAD ESR), where ESR is the effective series
resistance of COUT. ΔILOAD also begins to charge or dis-
charge COUT, which generates a feedback error 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 that would indicate a stability
problem. For a detailed explanation of switching control
loop theory, see Application Note 76.
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 paral-
lel 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 10μF capacitor charging to 3.3V
would require a 250μs rise time, limiting the charging
current to about 130mA.
PC Board Layout Checklist
When laying out the printed circuit board, the following
checklist should be used to ensure proper operation of the
LTC3406A. These items are also illustrated graphically in
Figures 3 and 4. Check the following in your layout:
1. The power traces, consisting of the GND trace, the SW
trace, the VOUT trace and the VIN trace should be kept
short, direct and wide.
2. Does the VFB pin connect directly to the feedback
resistors? The resistive divider R1/R2 must be
connected between the (+) plate of COUT and ground.
3. Does CIN connect to VIN as closely as possible? This
capacitor provides the AC current to the internal power
MOSFETs.
4. Keep the switching node, SW, away from the sensitive
VFB node.
5. Keep the (–) plates of CIN and COUT, and the IC ground,
as close as possible.
APPLICATIONS INFORMATION
相关PDF资料 |
PDF描述 |
|---|---|
| LTC3406AES5#TR | 1.3 A SWITCHING REGULATOR, 1800 kHz SWITCHING FREQ-MAX, PDSO5 |
| LTC3406AIS5#PBF | 1.3 A SWITCHING REGULATOR, 1800 kHz SWITCHING FREQ-MAX, PDSO5 |
| LTC3406AES5#PBF | 1.3 A SWITCHING REGULATOR, 1800 kHz SWITCHING FREQ-MAX, PDSO5 |
| LTC3406BES5#PBF | 1.25 A SWITCHING REGULATOR, 1800 kHz SWITCHING FREQ-MAX, PDSO5 |
| LTC3406BES5-1.8#PBF | 1.25 A SWITCHING REGULATOR, 1800 kHz SWITCHING FREQ-MAX, PDSO5 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3406AES5-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:1.5MHz, 600mA Synchronous Step-Down Regulator in ThinSOT |
| LTC3406AIS5#PBF | 制造商:Linear Technology 功能描述:DP-SWREG/Monolithic, Cut Tape 1.5MHz, 600mA Synch Step Down Regulator |
| LTC3406AIS5#TRMPBF | 功能描述:IC REG BUCK SYNC ADJ TSOT23-5 RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:升压（升压） 输出类型:可调式 输出数:1 输出电压:1.24 V ~ 30 V 输入电压:1.5 V ~ 12 V PWM 型:电流模式，混合 频率 - 开关:600kHz 电流 - 输出:500mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:8-SOIC |
| LTC3406AIS5#TRPBF | 功能描述:IC REG BUCK SYNC ADJ TSOT23-5 RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:升压（升压） 输出类型:可调式 输出数:1 输出电压:1.24 V ~ 30 V 输入电压:1.5 V ~ 12 V PWM 型:电流模式，混合 频率 - 开关:600kHz 电流 - 输出:500mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:8-SOIC |
| LTC3406AIS5-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:1.5MHz, 600mA Synchronous Step-Down Regulator in ThinSOT |
发布紧急采购，3分钟左右您将得到回复。