參數(shù)資料
型號： PTH08T250WAST
廠商： TEXAS INSTRUMENTS INC
元件分類： 電源模塊
英文描述： 1-OUTPUT DC-DC REG PWR SUPPLY MODULE
文件頁數(shù)： 19/39頁
文件大小： 2220K
代理商： PTH08T250WAST
UVLO
I
230
R
(k
)
V
4.6
=
W
-
V
I
GND
PTH08T250W
6
7
8
9
12
13
GND
C
I
+
UDG-07103
14
15
V
I
V
I
V
I
GND
V
I
21
Inhibit/UVLO
R
UVLO
SLTS278G – NOVEMBER 2010 – REVISED MARCH 2009
www.ti.com
ADJUSTING THE UNDERVOLTAGE LOCKOUT (UVLO)
The PTH08T250W power modules incorporate an input undervoltage lockout (UVLO). The UVLO feature
prevents the operation of the module until there is sufficient input voltage to produce a valid output voltage. This
enables the module to provide a clean, monotonic powerup for the load circuit, and also limits the magnitude of
current drawn from the regulator’s input source during the power-up sequence.
The UVLO characteristic is defined by the ON threshold (VTHD) voltage. Below the ON threshold, the Inhibit
control is overridden, and the module does not produce an output. The hysteresis voltage, which is the difference
between the ON and OFF threshold voltages, is set at 500 mV. The hysteresis prevents start-up oscillations,
which can occur if the input voltage droops slightly when the module begins drawing current from the input
source.
The UVLO feature of the PTH08T250W module allows for limited adjustment of the ON threshold voltage. The
adjustment is made via the Inhbit/UVLO Prog control pin (pin 11) using a single resistor (see Figure 27). When
pin 11 is left open circuit, the ON threshold voltage is internally set to its default value, which is 4.3 volts. The ON
threshold might need to be raised if the module is powered from a tightly regulated 12-V bus. Adjusting the
threshold prevents the module from operating if the input bus fails to completely rise to its specified regulation
voltage.
Equation 4 determines the value of RUVLO required to adjust VTHD to a new value. The default value is 4.3 V, and
it may only be adjusted to a higher value.
(4)
Table 6 lists the standard resistor values for RUVLO for different values of the on-threshold (VTHD) voltage.
Table 6. Standard RUVLO values for Various VTHD values
VTHD (V)
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
RUVLO (kΩ)
255
165
121
95.3
78.7
68.1
59.0
52.3
46.4
42.2
39.2
35.7
Figure 27. Undervoltage Lockout Adjustment Resistor Placement
26
Copyright 2010–2009, Texas Instruments Incorporated
Product Folder Link(s): PTH08T250W
相關(guān)PDF資料
PDF描述
PTH08T250WAD 1-OUTPUT DC-DC REG PWR SUPPLY MODULE
PTH08T250WAS 1-OUTPUT DC-DC REG PWR SUPPLY MODULE
PTH08T250WAZ 1-OUTPUT DC-DC REG PWR SUPPLY MODULE
PTH08T255WAS DC-DC REG PWR SUPPLY MODULE
PTH08T255WAZ DC-DC REG PWR SUPPLY MODULE
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
PTH08T250WAZ 功能描述:DC/DC轉(zhuǎn)換器 50A 4.5V to 14V Inp Non-Isolated RoHS:否 制造商:Murata 產(chǎn)品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標(biāo)稱）: 輸出端數(shù)量:1 輸出電壓（通道 1）:3.3 V 輸出電流（通道 1）:600 mA 輸出電壓（通道 2）: 輸出電流（通道 2）: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體尺寸:
PTH08T250WAZT 功能描述:DC/DC轉(zhuǎn)換器 50A 4.5V to 14V Inp Non-Isolated RoHS:否 制造商:Murata 產(chǎn)品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標(biāo)稱）: 輸出端數(shù)量:1 輸出電壓（通道 1）:3.3 V 輸出電流（通道 1）:600 mA 輸出電壓（通道 2）: 輸出電流（通道 2）: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體尺寸:
PTH08T250WBD 制造商:Texas Instruments 功能描述:
PTH08T255WAD 功能描述:DC/DC轉(zhuǎn)換器 40A,8-14V In,3-5.25V Out,Non-Iso Pwr Mod RoHS:否 制造商:Murata 產(chǎn)品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標(biāo)稱）: 輸出端數(shù)量:1 輸出電壓（通道 1）:3.3 V 輸出電流（通道 1）:600 mA 輸出電壓（通道 2）: 輸出電流（通道 2）: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體尺寸:
PTH08T255WAS 功能描述:DC/DC轉(zhuǎn)換器 40A,8-14V In,3-5.25V Out,Non-Iso Pwr Mod RoHS:否 制造商:Murata 產(chǎn)品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標(biāo)稱）: 輸出端數(shù)量:1 輸出電壓（通道 1）:3.3 V 輸出電流（通道 1）:600 mA 輸出電壓（通道 2）: 輸出電流（通道 2）: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體尺寸:
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