GRM155R61A105KE15D Просмотр технического описания (PDF) - ON Semiconductor
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GRM155R61A105KE15D
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GRM155R61A105KE15D Datasheet PDF : 13 Pages
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NCP729
APPLICATIONS INFORMATION
General
The NCP729 is a high performance 200 mA Very Low
Dropout Linear Regulator. This device delivers excellent
noise and dynamic performance. It features typical
quiescent current of 35 mA at no−load, ultra−low noise of
10 mVRMS and high PSRR of 72 dB at 1 kHz. Such excellent
dynamic parameters and small package size make the device
an ideal choice for powering the precision analog and noise
sensitive circuitry in portable applications. NCP729
requires very small voltage headroom for correct operation.
The dropout for 3.3 V voltage option is only 68 mV (typ.) A
logic EN input provides ON/OFF control of the output
voltage. When the EN is low the device consumes as low as
typ. 300 nA from the IN pin.
The device is fully protected in case of output overload,
output short circuit condition and overheating, assuring a
very robust design.
Part Number
C0402C105K8PACTU
C1005X5R1A105K
GRM155R61A105KE15D
0402ZD105KAT2A
MCCA000571
ECJ−0EB0J475M
Description
1 mF Ceramic ±10%,
10 V, 0402, X5R
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1 mF Ceramic ±10%,
50 V, 1206, X7R
4.7 mF Ceramic ±20%,
6.3 V, 0402, X5R
No−load Operation
The regulator remains stable and regulates the output
voltage properly within the ±2% tolerance limits with no
external load applied to the output.
Input Capacitor (CIN)
It is recommended to connect a minimum of 1 mF Ceramic
X5R or X7R capacitor close to the IN pin of the device. This
capacitor will provide a low impedance path for unwanted
AC signals or noise modulated onto constant input voltage.
There is no requirement for the min./max. ESR of the
input capacitor but it is recommended to use ceramic
capacitors for their low ESR and ESL. A good input
capacitor will limit the influence of input trace inductance
and power source resistance during sudden load current
changes. Larger input capacitor may be necessary if fast and
large line/load transients are encountered in the application.
Output Capacitor (COUT)
The NCP729 is designed to operate with a small 1.0 mF
ceramic capacitor on the output. To assure proper operation
it is recommended to use min. 1.0 mF capacitor with the
initial tolerance of ±10%, made of X7R or X5R dielectric
material types.
NCP729 is internally compensated so there is no
requirement for the minimum value of Equivalent Series
Resistance (ESR) for the COUT but the maximum value of
ESR should be less than 500 mW.
Larger output capacitors could be used to improve the load
transient response or high frequency PSRR. This part is not
designed to work with tantalum or electrolytic capacitors on
the output due to their large ESR and ESL. The equivalent
series resistance of tantalum capacitors is also strongly
dependent on the temperature, increasing at low
temperatures. The tantalum capacitors are generally more
costly than ceramic capacitors.
The table below lists examples of suitable output
capacitors:
Enable Operation
The NCP729 uses the EN pin to enable, disable its output
and to deactivate, activate the active output discharge
function.
If the EN pin voltage is <0.4 V the device is guaranteed to
be disabled. The pass transistor is turned−off and the active
discharge transistor is active so that the output voltage VOUT
is pulled to GND through a 1 kW resistor. In the disable state
the device consumes as low as typ. 300 nA from the VIN.
If the EN pin voltage > 0.9 V the device is guaranteed to
be enabled. The output voltage is regulated at the nominal
value and the active discharge transistor is turned−off.
The EN pin has internal pull−down current source with
typ. value of 110 nA which assures that the device is
turned−off when the EN pin is not connected. A build in
2 mV of hysteresis in the EN prevents from periodic on/off
oscillations that can occur due to noise.
In the case where the EN function isn’t required the EN
pin should be tied directly to IN.
Undervoltage Lockout
The internal UVLO circuitry assures that the device
becomes disabled when the VIN falls below typ. 1.5 V. When
the VIN voltage ramps−up the NCP729 becomes enabled for
VIN ≥ 1.6 V. The 100 mV hysteresis prevents from on/off
oscillations that can occur due to noise on VIN line.
Reverse Current
The PMOS pass transistor has an inherent body diode
which will be forward biased in the case that VOUT > VIN.
Due to this fact in cases where the extended reverse current
condition is anticipated the device may require additional
external protection.
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