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参数资料
| 型号： | DS2148T |
| 厂商： | DALLAS SEMICONDUCTOR |
| 元件分类： | Digital Transmission Interface |
| 英文描述： | DATACOM, PCM TRANSCEIVER, PQFP44 |
| 封装： | TQFP-44 |
| 文件页数： | 9/11页 |
| 文件大小： | 168K |
| 代理商： | DS2148T |
MAX860/MAX861
50mA, Frequency-Selectable,
Switched-Capacitor Voltage Converters
7
Maxim Integrated
__________Applications Information
Capacitor Selection
The MAX860/MAX861 are tested using 10F capacitors
for both C1 and C2, although smaller or larger values
can be used (Table 3). Smaller C1 values increase the
output resistance; larger values reduce the output
resistance. Above a certain point, increasing the
capacitance of C1 has a negligible effect (because the
output resistance becomes dominated by the internal
switch resistance and the capacitor ESR). Low-ESR
capacitors provide the lowest output resistance and
ripple voltage. The output resistance of the entire circuit
(inverter or doubler) is approximately:
ROUT = RO + 4 x ESRC1 + ESRC2 + 1 / (fS x C1)
where RO (the effective resistance of the MAX860/
MAX861’s internal switches) is approximately 8
Ω and fS
is the switching frequency. ROUT is typically 12
Ω when
using capacitors with 0.2
Ω ESR and fS, C1, and C2 val-
ues suggested in Table 3. When C1 and C2 are so
large (or the switching frequency is so high) that the
internal switch resistance dominates the output resis-
tance, estimate the output resistance as follows:
ROUT = RO + 4 x ESRC1 + ESRC2
A typical design procedure is as follows:
1) Choose C1 and C2 to be the same, for convenience.
2) Select fS:
a) If you want to avoid a specific noise frequency,
choose fS appropriately.
b) If you want to minimize capacitor cost and size,
choose a high fS.
c) If you want to minimize current consumption,
choose a low fS.
3) Choose a capacitor based on Table 3, although
higher or lower values can be used to optimize per-
formance. Table 4 lists manufacturers who provide
low-ESR capacitors.
*In addition to Table 3, four graphs in the
Typical
Operating Characteristics section show typical output
current for C1 and C2 capacitances ranging from
0.33F to 22F. Output current is plotted for inputs of
4.5V (5V - 10%) and 3.0V (3.3V - 10%), and also for
10% and 20% output droop from the ideal -VIN value.
ATTRIBUTE
LOWER
FREQUENCY
HIGHER
FREQUENCY
Output Ripple
Larger
Smaller
C1, C2 Values
Larger
Smaller
Supply Current
Smaller
Larger
C1, C2 (μF)
NOMINAL FREQUENCY (kHz)
6
68
13
47
50
10
100
4.7
130
4.7
250
2.2
Table 2. Switching-Frequency Trade-Offs
Table 3. Suggested Capacitor Values*
Table 4. Low-ESR Capacitor Manufacturers
MANUFACTURER–Series
PHONE
FAX
COMMENTS
AVX TPS Series
(803) 946-0629
(803) 626-3123
Low-ESR tantalum, SMT
AVX TAG Series
(803) 946-0629
(803) 626-3123
Low-cost tantalum, SMT
Matsuo 267 Series
(714) 969-2491
(714) 960-6492
Low-cost tantalum, SMT
Sprague 595 Series
(603) 224-1961
(613) 224-1430
Low-ESR tantalum, SMT
Sanyo MV-GX Series
(619) 661-6835
(619) 661-1055
Aluminum electrolytic, through hole
Sanyo CV-GX Series
(619) 661-6835
(619) 661-1055
Aluminum electrolytic, SMT
Nichicon PL Series
(847) 843-7500
(847) 843-2798
Aluminum electrolytic, through hole
United Chemicon (Marcon)
(847) 696-2000
(847) 696-9278
Ceramic SMT
TDK
(847) 390-4461
(847) 390-4405
Ceramic SMT
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| DS2148T+ | 功能描述:网络控制器与处理器 IC 5V E1/T1/J1 Line Interface RoHS:否 制造商:Micrel 产品:Controller Area Network (CAN) 收发器数量: 数据速率: 电源电流（最大值）:595 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PBGA-400 封装:Tray |
| DS2148TA2 | 功能描述:网络控制器与处理器 IC 5V E1/T1/J1 Line Interface RoHS:否 制造商:Micrel 产品:Controller Area Network (CAN) 收发器数量: 数据速率: 电源电流（最大值）:595 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PBGA-400 封装:Tray |
| DS2148TB | 功能描述:网络控制器与处理器 IC RoHS:否 制造商:Micrel 产品:Controller Area Network (CAN) 收发器数量: 数据速率: 电源电流（最大值）:595 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PBGA-400 封装:Tray |
| DS2148TC1 | 功能描述:网络控制器与处理器 IC RoHS:否 制造商:Micrel 产品:Controller Area Network (CAN) 收发器数量: 数据速率: 电源电流（最大值）:595 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PBGA-400 封装:Tray |
| DS2148TN | 功能描述:网络控制器与处理器 IC 5V E1/T1/J1 Line Interface RoHS:否 制造商:Micrel 产品:Controller Area Network (CAN) 收发器数量: 数据速率: 电源电流（最大值）:595 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PBGA-400 封装:Tray |
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