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參數(shù)資料
| 型號： | RT9166 |
| 英文描述： | Ultra-Fast Transient Response |
| 中文描述： | 超快速瞬態(tài)響應 |
| 文件頁數(shù)： | 8/16頁 |
| 文件大?。?/td> | 254K |
| 代理商： | RT9166 |
RT9166/A
Preliminary
www.richtek.com
8
DS9166A-03 July 2003
Application Information
Like any low-dropout regulator, the RT9166/A series
requires input and output decoupling capacitors.
These capacitors must be correctly selected for good
performance (see Capacitor Characteristics Section).
Please note that linear regulators with a low dropout
voltage have high internal loop gains which require
care in guarding against oscillation caused by
insufficient decoupling capacitance.
INPUT CAPACITOR
An input capacitance of
1
μ
F is required between the
device input pin and ground directly (the amount of
the capacitance may be increased without limit). The
input capacitor
MUST
be located less than 1 cm from
the device to assure input stability (see PCB Layout
Section). A lower ESR capacitor allows the use of
less capacitance, while higher ESR type (like
aluminum electrolytic) require more capacitance.
Capacitor types (aluminum, ceramic and tantalum)
can be mixed in parallel, but the total equivalent input
capacitance/ESR must be defined as above to stable
operation.
There are no requirements for the ESR on the input
capacitor, but tolerance and temperature coefficient
must be considered when selecting the capacitor to
ensure the capacitance will be
1
μ
F over the entire
operating temperature range.
OUTPUT CAPACITOR
The RT9166/A is designed specifically to work with
very
small
ceramic
output
recommended minimum capacitance (temperature
characteristics X7R or X5R) is 1
μ
F to 4.7
μ
F range
with 10m
to 50m
range ceramic capacitor
between LDO output and GND for transient stability,
but it may be increased without limit. Higher
capacitance values help to improve transient. The
output capacitor’s ESR is critical because it forms a
zero to provide phase lead which is required for loop
stability. (When using the Y5V dielectric, the
minimum value of the input/output capacitance that
can be used for stable over full operating
temperature range is 3.3
μ
F.)
capacitors.
The
NO LOAD STABILITY
The device will remain stable and in regulation with
no external load. This is specially important in CMOS
RAM keep-alive applications.
INPUT-OUTPUT (DROPOUT) VOLTAGE
A regulator’s minimum input-to-output voltage
differential (dropout voltage) determines the lowest
usable supply voltage. In battery-powered systems,
this determines the useful end-of-life battery voltage.
Because the device uses a PMOS, its dropout
voltage is a function of drain-to-source on-resistance,
R
DS(ON)
, multiplied by the load current:
V
DROUPOUT
= V
IN
– V
OUT
= R
DS(ON)
×
I
OUT
CURRENT LIMIT
The RT9166/A monitors and controls the PMOS
’
gate voltage, minimum limiting the output current to
300mA for RT9166 and 500mA for RT9166A. The
output can be shorted to ground for an indefinite
period of time without damaging the part.
SHORT-CIRCUIT PROTECTION
The device is short circuit protected and in the event
of a peak over-current condition, the short-circuit
control loop will rapidly drive the output PMOS pass
element off. Once the power pass element shuts
down, the control loop will rapidly cycle the output on
and off until the average power dissipation causes
the thermal shutdown circuit to respond to servo the
on/off cycling to a lower frequency. Please refer to
the section on thermal information for power
dissipation calculations.
CAPACITOR CHARACTERISTICS
It is important to note that capacitance tolerance and
variation with temperature must be taken into
consideration when selecting a capacitor so that the
minimum required amount of capacitance is provided
over the full operating temperature range. In general,
a good tantalum capacitor will show very little
capacitance variation with temperature, but a ceramic
may not be as good (depending on dielectric type).
相關PDF資料 |
PDF描述 |
|---|---|
| RT9166A | Ultra-Fast Transient Response |
| RT9167A | SHDN/BP. Low-Noise |
| RT9169 | Ultra Low Quiescent Current |
| RT9182A | SHDN.Fast Transient Response |
| RT9182B | SHDN.Fast Transient Response |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| RT9166/A-12C | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:300/600mA, Ultra-Fast Transient Response LDO Regulator |
| RT9166/A-12P | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:300/600mA, Ultra-Fast Transient Response LDO Regulator |
| RT9166/A-13C | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:300/600mA, Ultra-Fast Transient Response LDO Regulator |
| RT9166/A-13P | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:300/600mA, Ultra-Fast Transient Response LDO Regulator |
| RT9166/A-14C | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:300/600mA, Ultra-Fast Transient Response LDO Regulator |
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