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参数资料
| 型号： | LM4040AIM3-2.5Y |
| 厂商： | MICREL INC |
| 元件分类： | 基准电压源/电流源 |
| 英文描述： | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 2.5 V, PDSO3 |
| 封装： | SOT-23, 3 PIN |
| 文件页数： | 4/16页 |
| 文件大小： | 110K |
| 代理商： | LM4040AIM3-2.5Y |
LM4040/4041
Micrel
LM4040/4041
12
January 2000
Applications Information
The LM4040 and LM4041 have been designed for stable
operation without the need of an external capacitor con-
nected between the (+) and (–) pins. If a bypass capacitor is
used, the references remain stable.
Schottky Diode
LM4040-x.x and LM4041-1.2 in the SOT-23 package have a
parasitic Schottky diode between pin 2 (–) and pin 3 (die
attach interface connect). Pin 3 of the SOT-23 package must
float or be connected to pin 2. LM4041-ADJs use pin 3 as the
(–) output.
Conventional Shunt Regulator
In a conventional shunt regulator application (see Figure 1),
an external series resistor (R
S) is connected between the
supply voltage and the LM4040-x.x or LM4041-1.2 reference.
R
S determines the current that flows through the load (IL) and
the reference (I
Q). Since load current and supply voltage may
vary, R
S should be small enough to supply at least the
minimum acceptable I
Q to the reference even when the
supply voltage is at its minimum and the load current is at its
maximum value. When the supply voltage is at its maximum
and I
L is at its minimum, RS should be large enough so that
the current flowing through the LM4040-x.x is less than
15mA, and the current flowing through the LM4041-1.2 or
LM4041-ADJ is less than 12mA.
R
S is determined by the supply voltage (VS), the load and
operating current, (I
L and IQ), and the reference’s reverse
breakdown voltage (V
R).
R
s = (Vs – VR) / (IL + IQ)
Adjustable Regulator
The LM4041-ADJ’s output voltage can be adjusted to any
value in the range of 1.24V through 10V. It is a function of the
internal reference voltage (V
REF) and the ratio of the external
feedback resistors as shown in Figure 2. The output is found
using the equation
(1)
V
O = VREF [ (R2/R1) + 1 ]
where V
O is the desired output voltage. The actual value of
the internal V
REF is a function of VO. The “corrected” VREF is
determined by
(2)
V
REF = VO (VREF / VO) + VY
where V
O is the desired output voltage. VREF / VO is found
in the Electrical Characteristics and is typically –1.3mV/V and
V
Y is equal to 1.233V. Replace the value of VREF in equation
(1) with the value found using equation (2).
Note that actual output voltage can deviate from that pre-
dicted using the typical
V
REF / VO in equation (2); for C-
grade parts, the worst-case
V
REF / VO is –2.5mV/V and
V
Y = 1.248V.
The following example shows the difference in output voltage
resulting from the typical and worst case values of
V
REF / VO:
Let V
O = +9V. Using the typical values of VREF /VO , VREF
is 1.223V. Choosing a value of R1 = 10k
, R2 = 63.272k.
Using the worst case
V
REF / VO for the C-grade and D-
grade parts, the output voltage is actually 8.965V and 8.946V
respectively. This results in possible errors as large as 0.39%
for the C-grade parts and 0.59% for the D-grade parts. Once
again, resistor values found using the typical value of
V
REF / VO will work in most cases, requiring no further
adjustment.
Figure 4. Voltage Level Detector
R1
120k
R2
1M
FB
+
–
LM4041-ADJ
D1
λ
< –12V
LED ON
R3
200
–5V
D1
λ
LM4041-
ADJ
R1
120k
R2
1M
FB
–
+
R3
330
> –12V
LED ON
–5V
Figure 3. Voltage Level Detector
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM4040AIM3-3.0 | 功能描述:基准电压& 基准电流 RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel |
| LM4040AIM3-3.0/NOPB | 功能描述:基准电压& 基准电流 RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel |
| LM4040AIM3-3.0+ | 制造商:Maxim Integrated Products 功能描述:V-REF PRECISION 3V 15MA 3PIN SOT-23 - Rail/Tube |
| LM4040AIM3-3.0+T | 功能描述:基准电压& 基准电流 uPower Shunt V-Ref w/Mult Brkdwn V RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel |
| LM4040AIM3-3.0-T | 功能描述:基准电压& 基准电流 RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel |
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