- 您现在的位置：买卖IC网 > PDF目录14181 > LTC3221EDC#TRMPBF (Linear Technology)IC REG SWITCHED CAP DBL ADJ 6DFN PDF资料下载
参数资料
| 型号： | LTC3221EDC#TRMPBF |
| 厂商： | Linear Technology |
| 文件页数： | 9/12页 |
| 文件大小： | 0K |
| 描述： | IC REG SWITCHED CAP DBL ADJ 6DFN |
| 标准包装： | 500 |
| 类型： | 切换式电容器（充电泵），倍增器 |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 可调 |
| 输入电压： | 1.8 V ~ 5.5 V |
| PWM 型： | Burst Mode? |
| 频率 - 开关： | 600kHz |
| 电流 - 输出： | 60mA |
| 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： | 6-WFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 6-DFN-EP（2x2） |
LTC3221/
LTC3221-3.3/LTC3221-5
APPLICATIO S I FOR ATIO
be expressed by the following equation:
Programming the LTC3221 Output Voltage (FB Pin)
R OL ( MIN ) ≡
2 V IN – V OUT
I OUT
?
1
f OSC ? C FLY
While the LTC3221-3.3/LTC3221-5 versions have internal
resistive dividers to program the output voltage, the pro-
grammable LTC3221 may be set to an arbitrary voltage via
where f OSC is the switching frequency (600kHz) and C FLY
is the value of the ?ying capacitor. The charge pump will
typically be weaker than the theoretical limit due to ad-
an external resistive divider. Figure 3 shows the required
voltage divider connection.
V OUT = 1.23V (1 + )
ditionalswitchresistance.However,forverylightloadap-
plications, the above expression can be used as a guideline
in determining a starting capacitor value.
V OUT 6
LTC3221
3
FB
R1
C1
C OUT
R1
R2
Ceramic Capacitors
R2
Capacitors of different materials lose their capacitance
GND
4
3221 F03
= OUT – 1
with higher temperature and voltage at different rates.
For example, a ceramic capacitor made of X7R material
will retain most of its capacitance from –40°C to 85°C,
whereas,aZ5UorY5Vstylecapacitorwillloseconsiderable
capacitance over that range. Z5U and Y5V capacitors may
also have a very strong voltage coef?cient causing them
to lose 50% or more of their capacitance when the rated
voltage is applied. Therefore when comparing different
capacitors, it is often more appropriate to compare the
amount of achievable capacitance for a given case size
rather than discussing the speci?ed capacitance value.
For example, over rated voltage and temperature condi-
tions, a 1μF 10V Y5V ceramic capacitor in a 0603 case
may not provide any more capacitance than a 0.22μF 10V
X7R capacitor available in the same 0603 case. In fact,
for most LTC3221-3.3/LTC3221-5/LTC3221 applications,
these capacitors can be considered roughly equivalent. The
capacitor manufacturer’s data sheet should be consulted
to determine what value of capacitor is needed to ensure
0.6μF at all temperatures and voltages.
Table 1 shows a list of ceramic capacitor manufacturers
and how to contact them.
Table 1. Ceramic Capacitor Manufacturers
Figure 3. Programming the Adjustable LTC3221
The voltage divider ratio is given by the expression:
R 1 V
R 2 1 . 23 V
Since the LTC3221 employs a voltage doubling charge
pump, it is not possible to achieve output voltages greater
than twice the available input voltage. The V IN supply
range required for regulation is given by the following
expression:
Maximum V IN < V OUT + 0.6
Minimum V IN = ( V OUT + I OUT ? R OL ) or 1 . 8 V ;
2
whichever is higher
Where R OL is the effective open-loop output resistance and
I OUT is the maximum load current. V IN cannot be higher
than V OUT by more than 0.6V, or else the line regulation
is poor. Also, V IN has to be higher than the minimum
operating voltage of 1.8V.
AVX
Kemet
Murata
Taiyo Yuden
Vishay
www.avxcorp.com
www.kemet.com
www.murata.com
www.t-yuden.com
www.vishay.com
The sum of the voltage divider resistors can be made large
to keep the quiescent current to a minimum. Any standing
current in the output divider (given by 1.23/R2) will be
re?ected by a factor of 2 in the input current. A reasonable
resistance value should be such that the standing current
is in the range of 10μA to 100μA when V OUT is regulated.
3221f
9
相关PDF资料 |
PDF描述 |
|---|---|
| CGS443U060X5L | CAP ALUM 44000UF 60V SCREW |
| MIC4690YM TR | IC REG BUCK ADJ 1A 8SOIC |
| LNT2C153MSE | CAP ALUM 15000UF 160V 20% SCREW |
| CGS484U6R3W4C | CAP ALUM 480000UF 6.3V SCREW |
| CGS772U150X5C | CAP ALUM 7700UF 150V SCREW |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3225 | 制造商:LINEAR 制造商全称:LINEAR 功能描述:2-Cell Supercapacitor Charger with Backup |
| LTC3225-1 | 制造商:LINEAR 制造商全称:LINEAR 功能描述:2-Cell Supercapacitor Charger with Backup |
| LTC3225EDDB#PBF | 制造商:Linear Technology 功能描述:SUPERCAPACITOR CHARGER 5.5V 制造商:Linear Technology 功能描述:SUPERCAPACITOR CHARGER, 5.5V, DFN-10; IC Function:Supercapacitor Charger with Automatic Cell Balancing; Supply Voltage Min:2.8V; Supply Voltage Max:5.5V; Operating Temperature Min:-40C; Operating Temperature Max:85C; No. of Pins:10;RoHS Compliant: Yes |
| LTC3225EDDB#TRMPBF | 功能描述:IC SUPERCAP CHARGER 150MA 10DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:50 系列:- 应用:热电冷却器 电流 - 电源:- 电源电压:3 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:28-SOIC（0.173"，4.40mm 宽）裸露焊盘 供应商设备封装:28-TSSOP 裸露焊盘 包装:管件 产品目录页面:1410 (CN2011-ZH PDF) |
| LTC3225EDDB#TRPBF | 功能描述:IC SUPERCAP CHARGER 150MA 10DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 标准包装:1 系列:- 应用:手持/移动设备 电流 - 电源:- 电源电压:3 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-WFDFN 裸露焊盘 供应商设备封装:14-LLP-EP（4x4） 包装:Digi-Reel® 配用:LP3905SD-30EV-ND - BOARD EVALUATION LP3905SD-30 其它名称:LP3905SD-30DKR |
发布紧急采购，3分钟左右您将得到回复。