參數(shù)資料
型號： PTH08T221WAD
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
封裝： ROHS COMPLIANT, PLASTIC, DIP-11
文件頁數(shù)： 15/38頁
文件大小： 1290K
代理商： PTH08T221WAD
ADJUSTING THE UNDERVOLTAGE LOCKOUT (UVLO)
R
UVLO +
9690
* 137
V
I
137
V
I * 585
(kW)
(5)
2
3
4
11
GND
VI
RUVLO
CI
PTH08T220W/221W
Inhibit/UVLO Prog
SLTS252K – NOVEMBER 2005 – REVISED JUNE 2009................................................................................................................................................... www.ti.com
The PTH08T220/221W 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 PTH08T220/221W 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 21).
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 5 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.
Table 7 lists the standard resistor values for RUVLO for different values of the on-threshold (VTHD) voltage.
Table 7. Standard RUVLO values for Various VTHD values
VTHD
5.0 V
5.5 V
6.0 V
6.5 V
7.0 V
7.5 V
8.0 V
8.5 V
9.0 V
9.5 V
10.0 V
10.5 V
11.0 V
RUVLO
88.7 k
Ω 52.3 kΩ 37.4 kΩ 28.7 kΩ 23.2 kΩ 19.6 kΩ 16.9 kΩ 14.7 kΩ 13.0 kΩ 11.8 kΩ 10.5 kΩ 9.76 kΩ 8.87 kΩ
Figure 21. Undervoltage Lockout Adjustment Resistor Placement
22
Copyright 2005–2009, Texas Instruments Incorporated
Product Folder Link(s): PTH08T220W PTH08T221W
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相關代理商/技術參數(shù)
參數(shù)描述
PTH08T221WAD 制造商:Texas Instruments 功能描述:Power Module
PTH08T221WAS 功能描述:DC/DC轉換器 16A 4.5V to 14V Inp Ceramic Cap Version RoHS:否 制造商:Murata 產品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標稱）: 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）: 安裝風格:SMD/SMT 封裝 / 箱體尺寸:
PTH08T221WAST 功能描述:DC/DC轉換器 16A 4.5V to 14V Inp Ceramic Cap Version RoHS:否 制造商:Murata 產品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標稱）: 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）: 安裝風格:SMD/SMT 封裝 / 箱體尺寸:
PTH08T221WAZ 功能描述:DC/DC轉換器 16A 4.5V to 14V Inp Ceramic Cap Version RoHS:否 制造商:Murata 產品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標稱）: 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）: 安裝風格:SMD/SMT 封裝 / 箱體尺寸:
PTH08T221WAZT 功能描述:DC/DC轉換器 16A 4.5V to 14V Inp Ceramic Cap Version RoHS:否 制造商:Murata 產品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標稱）: 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）: 安裝風格:SMD/SMT 封裝 / 箱體尺寸:
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