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參數(shù)資料
| 型號： | RT9172F-32PG |
| 廠商： | Richtek Technology Corporation |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | 3A Fixed Output Voltage LDO Regulator |
| 中文描述： | 3A固定輸出電壓LDO穩(wěn)壓器 |
| 文件頁數(shù)： | 9/15頁 |
| 文件大?。?/td> | 236K |
| 代理商： | RT9172F-32PG |
RT9172
9
DS9172-14 March 2007
www.richtek.com
Application Information
Capacitor Selection
z
An output capacitor as part of the device frequency
compensation to maintain stability and improve
transient response.
z
Proper capacitor selection is important to ensure proper
operation. When the output capacitor is 10
μ
F or greater,
the output capacitor should have an ESR less than 2
Ω
.
This will improve transient response as well as promote
stability.
z
Ultra-low-ESR capacitor (<100m
Ω
), such as ceramic
chip capacitors, may promote instability. These very
low ESR levels may cause an oscillation and/or
underdamped transient response. A low-ESR solid
tantalum capacitor works extremely well and provides
good transient response and stability over temperature.
Aluminum electrolytics can also be used, as long as
the ESR of the capacitor is <2
Ω
. The value of the output
capacitor can be increased without limit. Higher
capacitor values help to improve transient response
and ripple rejection and reduce output noise.
The RT9172 requires a minimum input capacitance of
1
μ
F between the input and ground pins to prevent any
impedance interactions with the supply. The RT9172
requires a minimum of 10
μ
F (tantalum, or electrolytic)
capacitance between the output and ground pins for
proper operation. Please note that the part must be
paralleled with the least a 100
μ
F electrolytic capacitor
when using a 10
μ
F (or greater) ceramic type as the
output capacitor to prevent the output oscillating.
Error Operation (FLG)
The RT9172 produces a logic low signal at the FLG pin
when the output drops out of regulation due to low input
voltage, current limiting, or thermal limiting.
The internal error FLG comparator has an open drain
output stage. Hence, the FLG pin should be pulled high
through a pull up resistor.
Sense Pin
In applications where the regulator output is not very close
to the load, RT9172 can provide better remote load
regulation using the SENSE pin. Figure 2. and Figure 3.
depict the advantage of the SENSE option. RT9172
regulates the voltage at the output pin. Hence, the voltage
at the remote load will be the regulator output voltage
minus the drop across the trace resistance. For example,
in the case of a 3.3V output, if the trace resistance is
100m
Ω
, the voltage at the remote load will be 3V with 3A
of load current, I
LOAD
. The RT9172 regulates the voltage
at the sense pin. Connecting the sense pin to the remote
load will provide regulation at the remote load, as shown
in Figure 2. and Figure 3.
Chip Enable Operation
A CMOS logic level signal at the chip enable (EN) pin will
turn-off the regulator. Pin EN must be actively terminated
through a 10k
Ω
pull-up resistor for a proper operation. If
this pin is driven from a source that actively pulls high
and low (such as a CMOS rail to rail comparator), the
pull-up resistor is not required. This pin must be tied to
V
IN
if not used.
Dropout Voltage
The dropout voltage of a regulator is defined as the minimum
input-to-output differential required to stay within 2% of
the output voltage. The RT9172 uses an internal MOSFET
with an R
DS(ON)
160m
Ω
. For CMOS LDOs, the dropout
voltage is the product of the load current and the R
DS(ON)
of the internal MOSFET.
Maximum Output Current Capability
RT9172 can deliver a continuous current of 1.5 A over the
full operating temperature range. A heatsink may be required
depending on the maximum power dissipation and
maximum ambient temperature of the application. Under
all possible conditions, the junction temperature must be
within the range specified under operating conditions. The
total power dissipation of the device is given by : PD = (V
IN
- V
OUT
) I
OUT
+ (V
IN
) I
GND
where I
GND
is the operating ground current of the device
(specified under Electrical Characteristics).
相關PDF資料 |
PDF描述 |
|---|---|
| RT9172F-32PM | 3A Fixed Output Voltage LDO Regulator |
| RT9172F-32PM5 | 3A Fixed Output Voltage LDO Regulator |
| RT9172F-32PS | 3A Fixed Output Voltage LDO Regulator |
| RT9172F-32PT | 3A Fixed Output Voltage LDO Regulator |
| RT9172F-32PT5 | 3A Fixed Output Voltage LDO Regulator |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| RT9173AGL5 | 功能描述:IC REG BUS TERMINATIN 3A TO252-5 RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標準包裝:43 系列:- 應用:控制器，Intel VR11 輸入電壓:5 V ~ 12 V 輸出數(shù):1 輸出電壓:0.5 V ~ 1.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-VFQFN 裸露焊盤 供應商設備封裝:48-QFN（7x7） 包裝:管件 |
| RT9173AGM5 | 功能描述:IC REG BUS TERMINATIN 3A TO263-5 RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標準包裝:43 系列:- 應用:控制器，Intel VR11 輸入電壓:5 V ~ 12 V 輸出數(shù):1 輸出電壓:0.5 V ~ 1.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-VFQFN 裸露焊盤 供應商設備封裝:48-QFN（7x7） 包裝:管件 |
| RT9173APL5 | 制造商:Richtek Technology Corporation 功能描述: |
| RT9173APM5 | 制造商:Richtek Technology Corporation 功能描述: |
| RT9173BGL5 | 功能描述:IC REG BUS TERMINATIN 2A TO252-5 RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標準包裝:43 系列:- 應用:控制器，Intel VR11 輸入電壓:5 V ~ 12 V 輸出數(shù):1 輸出電壓:0.5 V ~ 1.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-VFQFN 裸露焊盤 供應商設備封裝:48-QFN（7x7） 包裝:管件 |
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