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參數資料
| 型號： | TPS76825Q |
| 廠商： | Texas Instruments, Inc. |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | Fast-Transient-Response 1-A Low-Dropout Voltage Regulators(快速瞬變反應1A低壓差2.5V線性穩(wěn)壓器) |
| 中文描述： | 快速瞬態(tài)響應1 -低壓差穩(wěn)壓器（快速瞬變反應第1A低壓差2.5V的線性穩(wěn)壓器） |
| 文件頁數： | 14/19頁 |
| 文件大?。?/td> | 279K |
| 代理商： | TPS76825Q |
TPS76815Q, TPS76818Q, TPS76825Q, TPS76827Q
TPS76828Q, TPS76830Q TPS76833Q, TPS76850Q, TPS76801Q
FAST-TRANSIENT-RESPONSE 1-A LOW-DROPOUT VOLTAGE REGULATORS
SLVS211B – JUNE 1999 – REVISED JULY 1999
14
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
APPLICATION INFORMATION
The TPS768xx family includes eight fixed-output voltage regulators (1.5 V, 1.8 V, 2.5 V, 2.7 V, 2.8 V, 3.0 V,
3.3 V, and 5.0 V), and offers an adjustable device, the TPS76801 (adjustable from 1.2 V to 5.5 V).
device operation
The TPS768xx features very low quiescent current, which remains virtually constant even with varying loads.
Conventional LDO regulators use a pnp pass element, the base current of which is directly proportional to the
load current through the regulator (I
B
= I
C
/
β
). The TPS768xx uses a PMOS transistor to pass current; because
the gate of the PMOS is voltage driven, operating current is low and invariable over the full load range.
Another pitfall associated with the pnp-pass element is its tendency to saturate when the device goes into
dropout. The resulting drop in
β
forces an increase in I
B
to maintain the load. During power up, this translates
to large start-up currents. Systems with limited supply current may fail to start up. In battery-powered systems,
it means rapid battery discharge when the voltage decays below the minimum required for regulation. The
TPS768xx quiescent current remains low even when the regulator drops out, eliminating both problems.
The TPS768xx family also features a shutdown mode that places the output in the high-impedance state
(essentially equal to the feedback-divider resistance) and reduces quiescent current to 2
μ
A. If the shutdown
feature is not used, EN should be tied to ground. Response to an enable transition is quick; regulated output
voltage is reestablished in typically 120
μ
s.
minimum load requirements
The TPS768xx family is stable even at zero load; no minimum load is required for operation.
FB - pin connection (adjustable version only)
The FB pin is an input pin to sense the output voltage and close the loop for the adjustable option . The output
voltage is sensed through a resistor divider network to close the loop as it is shown in Figure 26. Normally, this
connection should be as short as possible; however, the connection can be made near a critical circuit to
improve performance at that point. Internally, FB connects to a high-impedance wide-bandwidth amplifier and
noise pickup feeds through to the regulator output. Routing the FB connection to minimize/avoid noise pickup
is essential.
external capacitor requirements
An input capacitor is not usually required; however, a ceramic bypass capacitor (0.047
μ
F or larger) improves
load transient response and noise rejection if the TPS768xx is located more than a few inches from the power
supply. A higher-capacitance electrolytic capacitor may be necessary if large (hundreds of milliamps) load
transients with fast rise times are anticipated.
Like all low dropout regulators, the TPS768xx requires an output capacitor connected between OUT and GND
to stabilize the internal control loop. The minimum recommended capacitance value is 10
μ
F and the ESR
(equivalent series resistance) must be between 50 m
and 1.5
. Capacitor values 10
μ
F or larger are
acceptable, provided the ESR is less than 1.5
. Solid tantalum electrolytic, aluminum electrolytic, and
multilayer ceramic capacitors are all suitable, provided they meet the requirements described above. Most of
the commercially available 10
μ
F surface–mount ceramic capacitors, including devices from Sprague and
Kemet, meet the ESR requirements stated above.
相關PDF資料 |
PDF描述 |
|---|---|
| TPS76828Q | Fast-Transient-Response 1-A Low-Dropout Voltage Regulators(快速瞬變反應1A低壓差2.8V線性穩(wěn)壓器) |
| TPS76815Q | Fast-Transient-Response 1-A Low-Dropout Voltage Regulators(快速瞬變反應1A低壓差1.5V線性穩(wěn)壓器) |
| TPS76818Q | Fast-Transient-Response 1-A Low-Dropout Voltage Regulators(快速瞬變反應1A低壓差1.8V線性穩(wěn)壓器) |
| TPS76827Q | Fast-Transient-Response 1-A Low-Dropout Voltage Regulators(快速瞬變反應1A低壓差2.7V線性穩(wěn)壓器) |
| TPS76830Q | Fast-Transient-Response 1-A Low-Dropout Voltage Regulators(快速瞬變反應1A低壓差3.0V線性穩(wěn)壓器) |
相關代理商/技術參數 |
參數描述 |
|---|---|
| TPS76825QD | 功能描述:低壓差穩(wěn)壓器 - LDO Micropower LDO Reg RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負載調節(jié):0.3 % 輸出端數量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| TPS76825QDG4 | 功能描述:低壓差穩(wěn)壓器 - LDO Micropower LDO Reg RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負載調節(jié):0.3 % 輸出端數量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| TPS76825QDR | 功能描述:低壓差穩(wěn)壓器 - LDO Micropower LDO Reg RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負載調節(jié):0.3 % 輸出端數量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| TPS76825QDRG4 | 功能描述:低壓差穩(wěn)壓器 - LDO Micropower LDO Reg RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負載調節(jié):0.3 % 輸出端數量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| TPS76825QPWP | 功能描述:低壓差穩(wěn)壓器 - LDO Micropower LDO Reg RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負載調節(jié):0.3 % 輸出端數量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-20 |
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