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参数资料
| 型号： | LTC3406BES5#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 1.25 A SWITCHING REGULATOR, 1800 kHz SWITCHING FREQ-MAX, PDSO5 |
| 封装： | PLASTIC, MO-193, TSOT-23, 5 PIN |
| 文件页数： | 2/16页 |
| 文件大小： | 231K |
| 代理商： | LTC3406BES5#PBF |
10
LTC3406B
3406bfa
APPLICATIO S I FOR ATIO
WU
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Although all dissipative elements in the circuit produce
losses, two main sources usually account for most of the
losses in LTC3406B circuits: VIN quiescent current and I2R
losses. The VIN quiescent current loss dominates the
efficiency loss at very low load currents whereas the I2R
loss dominates the efficiency loss at medium to high load
currents. In a typical efficiency plot, the efficiency curve at
very low load currents can be misleading since the actual
power lost is of no consequence as illustrated in Figure 4.
2. I2R losses are calculated from the resistances of the
internal switches, RSW, and external inductor RL. In
continuous mode, the average output current flowing
through inductor L is “chopped” between the main
switch and the synchronous switch. Thus, the series
resistance looking into the SW pin is a function of both
top and bottom MOSFET RDS(ON) and the duty cycle
(DC) as follows:
RSW = (RDS(ON)TOP)(DC) + (RDS(ON)BOT)(1 – DC)
The RDS(ON) for both the top and bottom MOSFETs can
be obtained from the Typical Performance Charateristics
curves. Thus, to obtain I2R losses, simply add RSW to
RL and multiply the result by the square of the average
output current.
Other losses including CIN and COUT ESR dissipative
losses and inductor core losses generally account for less
than 2% total additional loss.
Thermal Considerations
In most applications the LTC3406B does not dissipate
much heat due to its high efficiency. But, in applications
where the LTC3406B is running at high ambient tempera-
ture with low supply voltage and high duty cycles, such
as in dropout, the heat dissipated may exceed the maxi-
mum junction temperature of the part. If the junction
temperature reaches approximately 150°C, both power
switches will be turned off and the SW node will become
high impedance.
To avoid the LTC3406B from exceeding the maximum
junction temperature, the user will need to do some
thermal analysis. The goal of the thermal analysis is to
determine whether the power dissipated exceeds the
maximum junction temperature of the part. The tempera-
ture rise is given by:
TR = (PD)(θJA)
where PD is the power dissipated by the regulator and θJA
is the thermal resistance from the junction of the die to the
ambient temperature.
Figure 4. Power Lost vs Load Current
1. The VIN quiescent current is due to two components:
the DC bias current as given in the electrical character-
istics and the internal main switch and synchronous
switch gate charge currents. The gate charge current
results from switching the gate capacitance of the
internal power MOSFET switches. Each time the gate is
switched from high to low to high again, a packet of
charge, dQ, moves from VIN to ground. The resulting
dQ/dt is the current out of VINthat is typically larger than
the DC bias current. In continuous mode, IGATECHG =
f(QT + QB) where QT and QB are the gate charges of the
internal top and bottom switches. Both the DC bias and
gate charge losses are proportional to VIN and thus
their effects will be more pronounced at higher supply
voltages.
LOAD CURRENT (mA)
POWER
LOSS
(W)
0.1
10
100
1000
3406B F04
1
0.1
0.01
0.001
0.0001
VOUT = 1.2V
VOUT = 1.8V
VOUT = 2.5V
VOUT = 1.5V
VIN = 3.6V
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3406BES5TRMPBF | 制造商:Linear Technology 功能描述:DC-DC Converter Step-Down 5.5V TSOT23-5 |
| LTC3406ES5 | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 2.5V to 5.5V 5-Pin TSOT-23 |
| LTC3406ES5#PBF | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 2.5V to 5.5V 5-Pin TSOT-23 制造商:Linear Technology 功能描述:IC DC-DC CONV 1.5 MHz 5-SOT-23 制造商:Linear Technology 功能描述:BUCK 5.5VIN 1.5MHZ 0.6A 5TSOT23 制造商:Linear Technology 功能描述:BUCK, 5.5VIN, 1.5MHZ, 0.6A, 5TSOT23 制造商:Linear Technology 功能描述:IC, DC-DC CONV, 1.5 MHz, 5-SOT-23; Primary Input Voltage:5.5V; No. of Outputs:1; Output Voltage:600mV; Output Current:600mA; No. of Pins:5; Operating Temperature Min:-40C; Operating Temperature Max:85C; Package / Case:5-SOT-23 ;RoHS Compliant: Yes |
| LTC3406ES5#TR | 功能描述:IC REG BUCK SYNC ADJ TSOT23-5 RoHS:否 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 |
| LTC3406ES5#TRM | 功能描述:IC REG BUCK SYNC ADJ TSOT23-5 RoHS:否 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 |
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