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参数资料
| 型号： | PT6440 |
| 厂商： | Texas Instruments, Inc. |
| 英文描述： | 6A Adjustable Step-Down ISR Family |
| 中文描述： | 6A 可调节步降 ISR 系列 |
| 文件页数： | 7/8页 |
| 文件大小： | 178K |
| 代理商： | PT6440 |
Application Notes
For technical support and more information, see inside back cover or visit www.ti.com
PT6440 Series
Using the Inhibit Function on the PT6440
Excalibur
5V/3.3V Bus Step-Down ISRs
For applications requiring output voltage On/Off control,
the 12-pin PT6440 series products incorporate an
Inhibit
function. This function may be used wherever there is a
requirement for the module to be switched off. The
function is provided by the
Inhibit
control (pin 1) input.
The ISR functions normally with pin 1 open-circuit,
1
providing a regulated output whenever a valid source
voltage is applied to V
in
, (pins 2–4), with respect to GND
(pins 5–8). When a low-level ground signal is applied
to pin 1, the regulator output is disabled.
Figure 1 shows an application schematic, which details
the typical use of the Inhibit function. Note the discrete
transistor (Q
1
). The Inhibit control has its own internal
pull-up to +V
in
potential. An open-collector or open-
drain device is required to control this pin.
2
The Inhibit pin control thresholds are given in Table 1.
Equation 1 may be used to determine the approximate
current drawn from the input source, and by Q
1
when the
regulator is placed in the inhibit state.
Table 1; Inhibit Control Requirements
3
Parameter
Min
Max
Enable (VIH)
Disable (VIL)
Transition Time
Vin – 0.5
-0.2V
10μs
4
Vin
0.5V
Equation 1; Off Input Current
I
stby
= V
in
÷
10k
± 20%
Notes:
1. Use an open-collector device (preferably a discrete
transistor) for the Inhibit input. A pull-up resistor is not
necessary. To disable the output voltage, the control pin
should be pulled low to less than +0.5VDC.
2. Do not control the Inhibit input with an external DC
voltage. This will lead to erratic operation of the ISR and
may over-stress the regulator.
3. Avoid capacitance greater than 500pF at the Inhibit
control pin. Excessive capacitance at this pin will cause the
ISR to produce a pulse on the output voltage bus at turn-
on.
4. Keep the On/Off transition to less than 10μs. This
prevents erratic operation of the ISR, which could cause
the output voltage to be momentarily higher than normal.
Figure 1
Turn-On Time:
In the circuit of Figure 1, turning Q
1
on
applies a low-voltage to the
Inhibit
control (pin 1) and
disables the regulator output. Correspondingly, turning
Q
1
off allows the
Inhibit
control pin to be pulled high by
its internal pull-up resistor. The ISR produces a fully
regulated output voltage within 10 milliseconds of the
release of the Inhibit control pin. The actual turn-on
time will vary with input voltage, output load, and the
total amount of load capacitance. Figure 2 shows the
typical rise in both output voltage and input current for a
PT6441 (3.3V) following the turn-off of Q
1
at time t =0.
The waveform was measured with a 5Vdc input voltage,
and 6 Adc resistive load.
Figure 2
C
in
+
C
out
+
Inhibit
+5V
+2.5V
COM
COM
Q1
BSS138
PT6442
2,3,4
5
–
8
12
9,10,11
Vin
Vo
Vo(adj)
GND
1
Inhibit*
-1
0
1
2
3
4
5
6
7
8
9
10
t (milliseconds)
I
IN
(2A/Div)
V
O
(2V/Div)
V
INH
(5V/Div)
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相关代理商/技术参数 |
参数描述 |
|---|---|
| PT6441 | 制造商:TI 制造商全称:Texas Instruments 功能描述:6-A 5-V/3.3-V Input Adjustable Integrated Switching Regulator |
| PT6441A | 功能描述:DC/DC转换器 3.3Vout 6A 5V-Inp Adj Step-Down ISR RoHS:否 制造商:Murata 产品: 输出功率: 输入电压范围:3.6 V to 5.5 V 输入电压（标称）: 输出端数量:1 输出电压（通道 1）:3.3 V 输出电流（通道 1）:600 mA 输出电压（通道 2）: 输出电流（通道 2）: 安装风格:SMD/SMT 封装 / 箱体尺寸: |
| PT6441C | 功能描述:DC/DC转换器 3.3Vout 6A 5V-Inp Adj Step-Down ISR RoHS:否 制造商:Murata 产品: 输出功率: 输入电压范围:3.6 V to 5.5 V 输入电压（标称）: 输出端数量:1 输出电压（通道 1）:3.3 V 输出电流（通道 1）:600 mA 输出电压（通道 2）: 输出电流（通道 2）: 安装风格:SMD/SMT 封装 / 箱体尺寸: |
| PT6441N | 功能描述:DC/DC转换器 3.3Vout 6A 5V-Inp Adj Step-Down ISR RoHS:否 制造商:Murata 产品: 输出功率: 输入电压范围:3.6 V to 5.5 V 输入电压（标称）: 输出端数量:1 输出电压（通道 1）:3.3 V 输出电流（通道 1）:600 mA 输出电压（通道 2）: 输出电流（通道 2）: 安装风格:SMD/SMT 封装 / 箱体尺寸: |
| PT6442 | 制造商:TI 制造商全称:Texas Instruments 功能描述:6-A 5-V/3.3-V Input Adjustable Integrated Switching Regulator |
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