Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.NET

X  

SI91871 Datasheet(PDF) 9 Page - Vishay Siliconix

Part # SI91871
Description  300-mA Ultra Low-Noise LDO Regulator With Discharge Option
Download  10 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  VISHAY [Vishay Siliconix]
Direct Link  http://www.vishay.com
Logo VISHAY - Vishay Siliconix

SI91871 Datasheet(HTML) 9 Page - Vishay Siliconix

Back Button SI91871 Datasheet HTML 2Page - Vishay Siliconix SI91871 Datasheet HTML 3Page - Vishay Siliconix SI91871 Datasheet HTML 4Page - Vishay Siliconix SI91871 Datasheet HTML 5Page - Vishay Siliconix SI91871 Datasheet HTML 6Page - Vishay Siliconix SI91871 Datasheet HTML 7Page - Vishay Siliconix SI91871 Datasheet HTML 8Page - Vishay Siliconix SI91871 Datasheet HTML 9Page - Vishay Siliconix SI91871 Datasheet HTML 10Page - Vishay Siliconix  
Zoom Inzoom in Zoom Outzoom out
 9 / 10 page
background image
Si91871
Vishay Siliconix
Document Number: 72012
S-51147—Rev. F, 20-Jun-05
www.vishay.com
9
DETAILED DESCRIPTION
The Si91871 is a low-noise, low drop-out and low quiescent
current linear voltage regulator, packaged in a small footprint
MLP33-5 package. The Si91871 can supply loads up to
300 mA. As shown in the block diagram, the circuit consists of
a bandgap reference error, amplifier, p-channel pass transistor
and feedback resistor string. An external bypass capacitor
connected to the BP pin reduces noise at the output.
Additional blocks, not shown in the block diagram, include a
precise current limiter, reverse battery and current protection
and thermal sensor.
Thermal Overload Protection
The thermal overload protection limits the total power
dissipation and protects the device from being damaged.
When the junction temperature exceeds 150_C, the device
turns the p-channel pass transistor off.
Reverse Battery Protection
The Si91871 has a battery reverse protection circuitry that
disconnects the internal circuitry when VIN drops below the
GND voltage. There is no current drawn in such an event.
When the SD pin is hardwired to VIN, the user must connect
the SD pin to VIN via a 100-kW resistor if reverse battery
protection is desired. Hardwiring the SD pin directly to the VIN
pin is allowed when reverse battery protection is not desired.
Noise Reduction
An external 10-nF bypass capacitor at BP is used to create a
low pass filter for noise reduction. The start-up time is fast,
since a power-on circuit pre-charges the bypass capacitor.
After the power-up sequence the pre-charge circuit is switched
to standby mode in order to save current. It is therefore not
recommended to use larger bypass capacitor values than
50 nF. When the circuit is used without a capacitor, stable
operation is guaranteed.
Auto-Discharge
The Si91871 VOUT has an internal 100-W (typ.) discharge path
to ground when the SD pin is low.
Stability
The circuit is stable with only a small output capacitor equal to
6 nF/mA (= 2 mF @ 300 mA). Since the bandwidth of the error
amplifier is around 1−3 MHz and the dominant pole is at the
output node, the capacitor should be capacitive in this range,
i.e., for 150-mA load current, an ESR <0.2 W is necessary.
Parasitic inductance of about 10 nH can be tolerated.
Safe Operating Area
The ability of the Si91871 to supply current is ultimately
dependent on the junction temperature of the pass device.
Junction temperature is in turn dependent on power
dissipation in the pass device, the thermal resistance of the
package and the circuit board, and the ambient temperature.
The power dissipation is defined as
PD = (VIN – VOUT) * IOUT .
Junction temperature is defined as
TJ = TA + ((PD * (RθJC + RθCA)).
To calculate the limits of performance, these equations must
be rewritten.
Allowable power dissipation is calculated using the equation
PD = (TJ − TA )/ (RθJC + RθCA)
While allowable output current is calculated using the equation
IOUT = (TJ − TA )/ (RθJC + RθCA) * (VIN – VOUT).
Ratings of the Si91871 that must be observed are
TJmax = 125 _C, TAmax = 85 _C, (VIN – VOUT)max = 5.3 V,
JC = 8 _C/W.
The value of RθCA is dependent on the PC board used. The
value of RθCA for the board used in device characterization is
approximately 46 _C/W.
Figure 1 shows the performance limits graphically for the
Si91871 mounted on the circuit board used for thermal
characterization.
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0
123
456
Figure 1. Safe Operating Area
VIN − VOUT (V)
(VIN − VOUT)MAX = 5.3 V
TA = 50_C
TA = 85_C
TA = 70_C
Vishay Siliconix maintains worldwide manufacturing capability. Products may be manufactured at one of several qualified locations. Reliability data for Silicon Technology and
Package Reliability represent a composite of all qualified locations.
For related documents such as package/tape drawings, part marking, and reliability data, see
http://www.vishay.com/ppg?72012.


Similar Part No. - SI91871

ManufacturerPart #DatasheetDescription
logo
Vishay Siliconix
SI91871 VISHAY-SI91871 Datasheet
183Kb / 9P
   300-mA Ultra Low-Noise LDO Regulator With Discharge Option
Rev. B, 03-Feb-03
SI91871 VISHAY-SI91871 Datasheet
143Kb / 10P
   300-mA Ultra Low-Noise LDO Regulator With Discharge Option
18-Jul-08
SI91871DMP-12-T1 VISHAY-SI91871DMP-12-T1 Datasheet
183Kb / 9P
   300-mA Ultra Low-Noise LDO Regulator With Discharge Option
Rev. B, 03-Feb-03
SI91871DMP-15-T1 VISHAY-SI91871DMP-15-T1 Datasheet
183Kb / 9P
   300-mA Ultra Low-Noise LDO Regulator With Discharge Option
Rev. B, 03-Feb-03
SI91871DMP-18-T1 VISHAY-SI91871DMP-18-T1 Datasheet
183Kb / 9P
   300-mA Ultra Low-Noise LDO Regulator With Discharge Option
Rev. B, 03-Feb-03
More results

Similar Description - SI91871

ManufacturerPart #DatasheetDescription
logo
Vishay Siliconix
SI91871 VISHAY-SI91871 Datasheet
183Kb / 9P
   300-mA Ultra Low-Noise LDO Regulator With Discharge Option
Rev. B, 03-Feb-03
SI91871 VISHAY-SI91871_V01 Datasheet
143Kb / 10P
   300-mA Ultra Low-Noise LDO Regulator With Discharge Option
18-Jul-08
SI91841 VISHAY-SI91841 Datasheet
121Kb / 9P
   150-mA Ultra Low-Noise LDO Regulator With Discharge Option
Rev. C, 29-Mar-04
SI91872 VISHAY-SI91872_V01 Datasheet
127Kb / 10P
   300-mA Low-Noise LDO Regulator With Error Flag and Discharge Option
18-Jul-08
SI91872 VISHAY-SI91872 Datasheet
115Kb / 9P
   300-mA Low-Noise LDO Regulator With Error Flag and Discharge Option
Rev. F, 20-Jun-05
SI91845 VISHAY-SI91845 Datasheet
126Kb / 9P
   150-mA Ultra Low-Noise LDO Regulator With Error Flag and Discharge Option
Rev. B, 29-Mar-04
SI91844 VISHAY-SI91844 Datasheet
90Kb / 9P
   150-mA Low-Noise LDO Regulator With Error Flag and Discharge Option
Rev. C, 01-Apr-02
logo
ON Semiconductor
NCP164C ONSEMI-NCP164C Datasheet
566Kb / 15P
   LDO Regulator, 300mA, Low Dropout Voltage, Ultra Low Noise, High PSRR with Power Good
January, 2020 ??Rev. 1
NCP164 ONSEMI-NCP164 Datasheet
365Kb / 10P
   LDO Regulator, 300mA, Low Dropout Voltage, Ultra Low Noise, High PSRR with Power Good
April, 2020 ??Rev. 0
NCV8164 ONSEMI-NCV8164 Datasheet
423Kb / 13P
   LDO Regulator, 300mA, Low Dropout Voltage, Ultra Low Noise, High PSRR with Power Good
February, 2020 ??Rev. 0
More results


Html Pages

1 2 3 4 5 6 7 8 9 10


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.NET
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com