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参数资料
| 型号： | LT3692IUH#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 5.8 A DUAL SWITCHING CONTROLLER, 2750 kHz SWITCHING FREQ-MAX, PQCC32 |
| 封装： | 5 X 5 MM, LEAD FREE, PLASTIC, MO-220WHHD, QFN-32 |
| 文件页数： | 7/36页 |
| 文件大小： | 526K |
| 代理商： | LT3692IUH#PBF |
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LT3692
15
3692f
APPLICATIONS INFORMATION
can be set between 2A and 4.8A for each channel via
a resistor from the ILIM pin to ground. The ILIM pin is
driven by a 12A current source. Setting resistor RLIM
sets the voltage present at the ILIM pin which determines
the maximum switch current as illustrated in Figure 6. A
capacitor from the ILIM pin to ground, or a resistor divider
from the output, can be used to limit the peak current dur-
ing start-up. If a capacitor is used it must be discharged
before power-up to ensure proper operation (see 3.3V and
1.8V 2-Stage Dual Step-Down Multi-Frequency Converter
in Typical Applications).
Referring to Figure 6, as the peak current limit is reduced,
slope compensation further reduces the peak current with
increasing duty cycle.
When the ILIM pin is used to reduce the peak switch cur-
rent, the equation for inductor choice becomes:
L
=
50 VOUT
f RILIM
where f is frequency in MHz, L in H and R in kΩ.
When the LT3692’s input supplies are operated at different
input voltages, an input capacitor sized for that channel
should be placed as close as possible to the respective
VIN pins.
A caution regarding the use of ceramic capacitors at the
input. A ceramic input capacitor can combine with stray
inductance to form a resonant tank circuit. If power is
applied quickly (for example by plugging the circuit into
a live power source) this tank can ring, doubling the in-
put voltage and damaging the LT3692. The solution is to
either clamp the input voltage or dampen the tank circuit
by adding a lossy capacitor in parallel with the ceramic
capacitor. For details, see Application Note 88.
Output Capacitor Selection
Typicallystep-downregulatorsareeasilycompensatedwith
an output crossover frequency that is 1/10 of the switch-
ing frequency. This means that the time that the output
capacitor must supply the output load during a transient
step is ~2 or 3 switching periods. With an allowable 1%
drop in output voltage during the step, a good starting
value for the output capacitor can be expressed by:
CVOUT =
Max Load Step
Frequency 0.01 VOUT
Example:
VOUT = 3.3V, Frequency = 1MHz, Max Load Step = 2A.
CVOUT =
2
1E6 0.01 3.3V
= 60F
The calculated value is only a suggested starting value.
Increasethevalueiftransientresponseneedsimprovement
or reduce the capacitance if size is a priority. The output
capacitor filters the inductor current to generate an output
with low voltage ripple. It also stores energy in order to
satisfy transient loads and to stabilize the LT3692’s control
loop. The switching frequency of the LT3692 determines
the value of output capacitance required. Also, the current
mode control loop doesn’t require the presence of output
capacitor series resistance (ESR). For these reasons, you
are free to use ceramic capacitors to achieve very low
output ripple and small circuit size.
Figure 6. Peak Switch Current vs ILIM Resistor
Input Capacitor Selection
Bypass the inputs of the LT3692 circuit with a 4.7F or
higher ceramic capacitor of X7R or X5R type. A lower
value or a less expensive Y5V type can be used if there
is additional bypassing provided by bulk electrolytic or
tantalum capacitors.
ILIM PIN RESISTOR (k)
0
1.0
PEAK
SWITCH
CURRENT
(A)
1.5
2.5
3.0
3.5
4.5
10
50
70
3692 F06
2.0
4.0
40
90 100
20 30
60
80
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3693 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic Dual Tracking |
| LT36931DD#PBF | 制造商:Linear Technology 功能描述: |
| LT3693EDD#PBF | 功能描述:IC REG BUCK ADJ 3.5A 10DFN 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:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2 |
| LT3693EDD#TRPBF | 功能描述:IC REG BUCK ADJ 3.5A 10DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
| LT3693EDDPBF | 制造商:Linear Technology 功能描述:DC-DC Converter Step-Down 3.6-36V DFN10 |
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