参数资料
| 型号： | LTC3831EGN |
| 厂商： | Linear Technology |
| 文件页数： | 13/20页 |
| 文件大小： | 0K |
| 描述： | IC SW REG CONTROLLR SYNC 16-SSOP |
| 标准包装： | 100 |
| 应用： | 控制器，DDR |
| 输入电压： | 3 V ~ 8 V |
| 输出数： | 1 |
| 输出电压： | 1.27 V ~ 4 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-SSOP（0.154"，3.90mm 宽） |
| 供应商设备封装： | 16-SSOP |
| 包装： | 管件 |
| 产品目录页面： | 1336 (CN2011-ZH PDF) |
LTC3831
APPLICATIONS INFORMATION
V DDQ
5V
2.5V
MBR0530T1
+
C IN
330μF
× 2
1μF
PV CC2
PV CC1
10k
0.1μF
Q1
MBRS340T3
+
0.1μF
4.7μF
0.01μF
130k
V CC TG
SS I MAX
LTC3831 I FB
FREQSET BG
1k
0.1μF
Q2
L O
1.2μH
MBRS340T3
V TT
1.5V
±6A
SHDN
SHDN
PGND
+
C OUT
470μF
C1
33pF
R C
15k
COMP
GND
R +
C IN : SANYO POSCAP 6TPB330M
C OUT : SANYO POSCAP 4TPB470M
Q1, Q2: SILICONIX Si4410DY
× 3
2k
1%
C C
1500pF
R –
FB
10k
1%
3831 F08
Figure 8. Typical Application with V TT = 0.6 ? V DDQ
DC(Q1) = OUT
DC(Q2) = 1– OUT = IN
Power MOSFETs
Two N-channel power MOSFETs are required for most
LTC3831 circuits. These should be selected based primarily
on threshold voltage and on-resistance considerations.
Thermal dissipation is often a secondary concern in high
ef?ciency designs. The required MOSFET threshold should
be determined based on the available power supply volt-
ages and/or the complexity of the gate drive charge pump
scheme. In 3.3V input designs where an auxiliary 12V
supply is available to power PV CC1 and PV CC2 , standard
MOSFETs with R DS(ON) speci?ed at V GS = 5V or 6V can
be used with good results. The current drawn from this
supply varies with the MOSFETs used and the LTC3831’s
operating frequency, but is generally less than 50mA.
After the MOSFET threshold voltage is selected, choose
the R DS(ON) based on the input voltage, the output voltage,
allowable power dissipation and maximum output current.
In a typical LTC3831 circuit operating in continuous mode,
the average inductor current is equal to the output load
current. This current ?ows through either Q1 or Q2 with the
power dissipation split up according to the duty cycle:
V
V IN
V V – V OUT
V IN V IN
The R DS(ON) required for a given conduction loss can now
be calculated by rearranging the relation P = I 2 R.
LTC3831 applications that use 5V or lower V IN voltage and
doubling/tripling charge pumps to generate PV CC1 and
PV CC2 , do not provide enough gate drive voltage to fully
enhance standard power MOSFETs. Under this condition,
the effective MOSFET R DS(ON) may be quite high, raising
the dissipation in the FETs and reducing ef?ciency. Logic-
R DS(ON)Q1 =
R DS(ON)Q2 =
P MAX(Q1)
DC(Q1) ? (I LOAD ) 2
P MAX(Q2)
DC(Q2) ? (I LOAD ) 2
=
=
V IN ? P MAX(Q1)
V OUT ? (I LOAD ) 2
V IN ? P MAX(Q2)
(V IN – V OUT ) ? (I LOAD ) 2
level FETs are the recommended choice for 5V or lower
voltage systems. Logic-level FETs can be fully enhanced
with a doubler/tripling charge pump and will operate at
maximum ef?ciency.
P MAX should be calculated based primarily on required
ef?ciency or allowable thermal dissipation. A typical high
ef?ciency circuit designed for 2.5V input and 1.25V at 5A
3831fb
13
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| LTC3831EGN#PBF | 功能描述:IC SW REG CONTROLLR SYNC 16-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
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| LTC3831EGN#TRPBF | 功能描述:IC SW REG CONTROLLR SYNC 16-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
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