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Si91821
Vishay Siliconix
Micropower 300-mA CMOS LDO Regulator With Error Flag
FEATURES
D Input Voltage: 2.35-6.0 V D Fixed 1.8-V, 2.5-V, 2.8-V, 3.0-V, 3.3-V, 5.0-V, or Adjustable Output Voltage Options D Low 120-mV Dropout at 300-mA Load D Guaranteed 300-mA Output Current D 500-mA Peak Output Current Capability D Uses Low ESR Ceramic Output Capacitor D Fast Load and Line Transient Response D Only 100-mV(rms) Noise With Noise Bypass Capacitor D 1-mA Maximum Shutdown Current D Built-in Short Circuit and Thermal Protection D Out-Of-Regulation Error Flag (Power_Good)
Available
APPLICATIONS
D Cellular Phones D Laptop and Palm Computers D PDA, Digital Still Cameras
DESCRIPTION
The Si91821 is a 300-mA CMOS LDO (low dropout) voltage regulator. The device features ultra low ground current and dropout voltage to prolong battery life in portable electronics. The Si91821 offers line and load transient response and ripple rejection superior to that of bipolar or BiCMOS LDO regulators. The device is designed to maintain regulation while delivering 500-mA peak current. This is useful for systems that have high surge current upon turn-on. The Si91821 is designed to drive the lower cost ceramic, as well as tantalum, output capacitors. The device is guaranteed stable from maximum load current down to 0-mA load. In addition, an external noise bypass capacitor connected to the device's CNOISE pin will lower the LDO's output noise for low noise applications. The Si91821 also includes an out-of-regulation error flag. When the output voltage is 5% below its nominal output voltage, the error flag output goes low. The Si91821 is available in both standard and lead (Pb)-free MSOP-8 packages and is specified to operate over the industrial temperature range of -40 _C to 85 _C.
TYPICAL APPLICATIONS CIRCUITS
7 VIN 2.2 mF GND 3 2 6 SD VIN CNOISE GND ERROR VOUT SET 8 1, 4 5 2.2 mF Optional 2.2 mF GND 3 VOUT VIN 7 2 6 SD VIN CNOISE GND ERROR VOUT SET 8 1, 4 5 2.2 mF VOUT
Si91821 Figure 1. Fixed Output Figure 2..
Si91821 Adjustable Output
ON/OFF VIN 2.2 mF GND
7 2 6 0.033 mF 3
SD VIN CNOISE GND
ERROR VOUT SET
8 1, 4 5 1 MW
POWER_GOOD VOUT 2.2 mF
Si91821 Figure 3.
Document Number: 71614 S-51147-Rev. E, 20-Jun-05
Fixed Output, Low Noise, Full Features Application
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Si91821
Vishay Siliconix
ABSOLUTE MAXIMUM RATINGS
Input Voltage, VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5 V SD Input Voltage, VSD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 V to VIN Output Current, IOUT . . . . . . . . . . . . . . . . . . . . . . . . . . Short Circuit Protected Output Voltage, VOUT . . . . . . . . . . . . . . . . . . . . . . . . -0.3 V to VO(nom) + 0.3 V Maximum Junction Temperature, TJ(max) . . . . . . . . . . . . . . . . . . . . . . . 150_C Storage Temperature, TSTG . . . . . . . . . . . . . . . . . . . . . . . . . . -55_C to 150_C ESD (Human Body Model) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 kV Power Dissipation (Package)a 8-Pin MSOPb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 666 mW Thermal Impedance (QJA)a 8-Pin MSOPb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185_C/W Notes a. Device mounted with all leads soldered or welded to PC board. b. Derate 10 mW/_C above TA = 25_C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
RECOMMENDED OPERATING RANGE
Input Voltage, VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.35 V to 6 V Output Voltage, VOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 to 5.0 V SD Input Voltage, VSD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V to VIN IOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to 300 mA Operating Ambient Temperature, TA . . . . . . . . . . . . . . . . . . . . -40_C to 85_C Operating Junction Temperature, TJ . . . . . . . . . . . . . . . . . . . -40_C to 125_C
CIN = 2.2 mF, COUT = 2.2 mF (ceramic, X5R or X7R type) , CNOISE = 0.033 mF (ceramic) COUT Range = 1 mF to 10 mF ("10%, x5R or x7R type) CIN w COUT
SPECIFICATIONS
Test Conditions Unless Otherwise Specified Parameter
Input Voltage Output Voltage Output Voltage Accuracy (to stated output voltage) Feedback Voltage (ADJ Version) Line Regulation (Except 5-V Version) Line Regulation (5-V Version) Line Regulation (ADJ Version) VIN DVOUT 100 VOUT(nom)
Limits
-40 to 85_C
Symbol
VIN VOUT VOUT VSET
VIN = VOUT(nom) + 1 V IOUT = 1 mA V, A CIN = 2.2 mF, COUT = 2.2 mF, VSD = 1.5 V
Tempa
Minb
2.35
Typc
Maxb
6.0 5.0 1.5 2.5
Unit
Adjustable Version 1 mA v IOUT v 300 mA
Full Room Full Room Full
1.5 -1.5 -2.5 1.191 1.179 -0.18 -0.18 -0.18 -0.18 5 80 120 150 500 600 0.1 500 260 37 54 60 50 40 1.215
V % VOUT(nom) V
1.239 1.251 0.18 0.18 0.18 0.18 20 135 200 270
From VIN = VOUT(nom) + 1 V to VOUT(nom) + 2 V From VIN = 5.5 V to 6 V VOUT = 1.5 V From VIN = 2.5 V to 3.5 V VOUT = 5 V From VIN = 5.5 V to 6 V IOUT = 10 mA VIN - VOUT IOUT = 200 mA IOUT = 300 mA IOUT = 0 mA
Full Full Full Full Room Full Full Full Room Room Room Room Room Room Room Room Room Room
%/V
Dropout p
Voltaged g
mV
Ground Pin Current Shutdown Supply Current Peak Output Current
IGND IIN(off) IO(peak)
IOUT = 200 mA IOUT = 300 mA VSD = 0 V VOUT w 0.95 x VOUT(nom), tpw = 2 ms BW = 10 Hz to 100 kHz IOUT = 150 mA BW = 10 to 100 kHz IOUT = 10 mA IOUT = 150 mA w/o CNOISE CNOISE = 0.1 mF CNOISE = 33 nF f = 1 kHz
mA 1 mA
Output Noise Voltage
eN
mV (rms)
Ripple Rejection pp j
DVOUT/DVIN
f = 10 kHz f = 100 kHz
dB
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Document Number: 71614 S-51147-Rev. E, 20-Jun-05
Si91821
Vishay Siliconix
SPECIFICATIONS
Test Conditions Unless Otherwise Specified Parameter Symbol
VIN = VOUT(nom) + 1 V, IOUT = 1 mA CIN = 2.2 mF, COUT = 2.2 mF, VSD = 1.5 V
Limits
-40 to 85_C
Tempa
Minb
Typc
Maxb
Unit
Dynamic Line Regulation Dynamic Load Regulation Turn-on Overshoot VOUT Turn-On-Time
DVO(line) DVO(load) DVOOS tON
VIN : VOUT(nom) + 1 V to VOUT(nom) + 2 V tr/tf = 5 ms, IOUT = 250 mA IOUT : 1 mA to 150 mA, tr/tf = 2 ms VIN followed by SD = High Event CNOISE v 100 nF COUT = 10 mF, VOUT to 90% of final value, VIN = 3.6 V
Room Room Room Room
10 30 2.5 350
mV % mS
Thermal Shutdown
Thermal Shutdown Junction Temp Thermal Hysteresis Short Circuit Current TJ(s/d) THYST ISC VOUT = 0 V Room Room Room 165 20 800 _C mA
Shutdown Input
SD Input Voltage SD Input Currente Shutdown Hysteresis VIH VIL IIH IIL VHYST High = Regulator ON (Rising) Low = Regulator OFF (Falling) VSD = 0 V, Regulator OFF VSD = 6 V, Regulator ON Full Full Room Room Full 0.01 1.0 100 1.5 VIN 0.4 V mA mV
Error Output
Output High Leakage Output Low Voltage Power_Good Trip Threshold f, g (Rising) Hysteresis f Error Delay IOFF VOL VTH VHYST tDELAY CNOISE v 100 nF ERROR = VOUT(nom) ISINK = 2 mA Full Full Full Room Full 0.93 x VOUT 0.95 x VOUT 2% x VOUT 10 mS 0.01 2 0.4 0.97 x VOUT V mA
Notes a. Room = 25_C, Full = -40 to 85_C. b. The algebraic convention whereby the most negative value is a minimum and the most positive a maximum. c. Typical values are for DESIGN AID ONLY, not guaranteed nor subject to production testing and are measured at TA = 25_C. d. The dropout voltage is defined as VIN - VOUT when VOUT is 100 mV below the value of VOUT for VIN = VOUT + 2 V. This is applicable for voltages of 2.5 V or higher. e. The device's shutdown pin includes a typical 6-MW internal pull-down resistor connected to ground. f. VOUT is defined as the output voltage of the DUT at 1 mA. g. Typical only, from VOUT = 2.0 V to VOUT = 1.5 V.
Document Number: 71614 S-51147-Rev. E, 20-Jun-05
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Si91821
Vishay Siliconix
TIMING WAVEFORMS
VIH SD tON VNOM = 0.95 VNOM VOUT VIL
ERROR
tDELAY
tDELAY
Figure 4.
Timing Diagram for Power-Up
PIN CONFIGURATION
MSOP-8
vOUT vIN GND VOUT
1 2 3 4 8 7 6 5
ERROR SD CNOISE SET
Top View
PIN DESCRIPTION
Pin Number
1, 4 2 3 5 6 7 8 www.vishay.com
Name
VOUT VIN GND SET CNOISE SD ERROR
Function
Output voltage. Connect COUT between this pin and ground. Input supply pin. Bypass this pin with a 2.2-mF ceramic or tantalum capacitor to ground. Ground pin. Local ground for CNOISE and COUT. For fixed output voltage versions, this pin could be connected to GND. For adjustable output voltage version, this voltage feedback pin sets the output voltage via an external resistor divider. Noise bypass pin. For low noise applications, a 0.01-mF or larger ceramic capacitor should be connected from this pin to ground. By applying less than 0.4 V to this pin, the device will be turned off. Connect this pin to VIN if unused. This open drain output is an error flag output which goes low when VOUT drops 5% below its nominal voltage. Document Number: 71614 S-51147-Rev. E, 20-Jun-05
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Si91821
Vishay Siliconix
BLOCK DIAGRAM
Switches shown for device in normal operating mode (SD = HIGH) 5 VIN CIN 2.2 mF 2 SET 6 CNOISE
SD ON OFF
7
RFB2 6 MW RFB1 +
+ - 60 mV 2 mA + -
To VIN
1, 4 COUT 2.2 mF REXT
VOUT
GND
3
1.215 V VREF
+ -
- +
8
ERROR
Figure 5.
300-mA CMOS LDO Regulator
5 VIN CIN 2.2 mF 2
SET
6
CNOISE
R2 SD ON OFF 6 MW + + - 7 VSET R1 + - 60 mV 2 mA To VIN 1, 4 COUT 2.2 mF REXT
VOUT
GND
3
1.215 V VREF
+ -
- +
8
ERROR
Figure 6.
Document Number: 71614 S-51147-Rev. E, 20-Jun-05
300-mA CMOS LDO Regulator (Adjustable Output)
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Si91821
Vishay Siliconix
DETAILED DESCRIPTION
The Si91821 is a low drop out, low quiescent current, and very linear regulator with very fast transient response. It is primarily designed for battery powered applications where battery run time is at a premium. The low quiescent current allows extended standby time while low drop out voltage enables the system to fully utilize battery power before recharge. The Si91821 is a very fast regulator with bandwidth exceeding 50 kHz while maintaining low quiescent current at light load conditions. With this bandwidth, the Si91821 is the fastest LDO available today. The Si91821 is stable with any output capacitor type from 1 mF to 10.0 mF. However, X5R or X7R ceramic capacitors are recommended for best output noise and transient performance. VIN VIN is the input supply pin. The bypass capacitor for this pin is not critical as long as the input supply has low enough source impedance. For practical circuits, a 1.0-mF or larger ceramic capacitor is recommended. When the source impedance is not low enough and/or the source is several inches from the Si91821, then a larger input bypass capacitor is needed. It is required that the equivalent impedance (source impedance, wire, and trace impedance in parallel with input bypass capacitor impedance) must be smaller than the input impedance of the Si91821 for stable operation. When the source impedance, wire, and trace impedance are unknown, it is recommended that an input bypass capacitor be used of a value that is equal to or greater than the output capacitor. VOUT VOUT is the output voltage of the regulator. Connect a bypass capacitor from VOUT to ground. The output capacitor can be any value from 1.0 mF to 10.0 mF. A ceramic capacitor with X5R or X7R dielectric type is recommended for best output noise, line transient, and load transient performance. GND Ground is the common ground connection for VIN and VOUT. It is also the local ground connection for CNOISE, SET, and SD. SET SET is not connected internally for the fixed voltage version. Therefore, it can be connected to GND optionally. For the adjustable output version, use a resistor divider R1 and R2, connect R1 from VOUT to SET and R2 from SET to ground. R2 should be in the 25-kW to 150-kW range for low power consumption, while maintaining adequate noise immunity. The formula below calculates the value of R1, given the desired output voltage and the R2 value.
R1 + VOUT * VSET R 2 VSET (1)
VSET is nominally 1.215 V.
SHUTDOWN (SD) SD controls the turning on and off of the Si91821. VOUT is guaranteed to be on when the SD pin voltage equals or is greater than 1.5 V. VOUT is guaranteed to be off when the SD pin voltage equals or is less than 0.4 V. During shutdown mode, the Si91821 will draw less than 2-mA current from the source. To automatically turn on VOUT whenever the input is applied, tie the SD pin to VIN. ERROR ERROR is an open drain output that goes low when VOUT is less than 5% of its normal value. As with any open drain output, an external pull up resistor is needed. This function is active in shutdown. The ERROR pin must be left opened if not used. CNOISE For low noise application, connect a high frequency ceramic capacitor from CNOISE to ground. A 0.01-mF or a 0.1-mF X5R or X7R is recommended.
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Document Number: 71614 S-51147-Rev. E, 20-Jun-05
Si91821
Vishay Siliconix
ORDERING INFORMATION
Standard Part Number
Si91821DH-18-T1 Si91821DH-25-T1 Si91821DH-28-T1 Si91821DH-30-T1 Si91821DH-33-T1 Si91821DH-50-T1 SI91821DH-AD-T1
Lead (Pb)-Free Part Number
Si91821DH-18-T1--E3 Si91821DH-25-T1--E3 Si91821DH-28-T1--E3 Si91821DH-30-T1--E3 Si91821DH-33-T1--E3 Si91821DH-50-T1--E3 SI91821DH-AD-T1--E3
Marking
1821 1800 1821 2500 1821 2800 1821 3000 1821 3300 1821 5000 1821 ADJ
Voltage
1.80 V 2.50 V 2.80 V 3.00 V 3.30 V 5.00 V Adjustable
Temperature Range
Package
-40 to 85_C
MSOP-8
Eval Kit
Si91821DB
Temperature Range
-40 to 85_C
Board Type
Surface Mount
TYPICAL CHARACTERISTICS (INTERNALLY REGULATED, 25_C UNLESS NOTED)
Dropout Voltage vs. Load Current
250 VOUT = 2.775 V 200 2.5 V DROP (mV) V OUT (V) 150 2.0 1.5 1.0 50 0.5 0 0 100 200 300 400 500 ILOAD (mA) 0.0 0 1 3.5 3.0
Dropout Characteristic
VOUT = 2.775 V RLOAD = 16.5 W
100
2
3 VIN (V)
4
5
6
Document Number: 71614 S-51147-Rev. E, 20-Jun-05
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Si91821
Vishay Siliconix
TYPICAL CHARACTERISTICS (INTERNALLY REGULATED, 25_C UNLESS NOTED)
Dropout Voltage vs. Temperature
180 VOUT = 2.775 V 150 120 V DROP (mV) 90 60 30 0 -50 IOUT = 10 mA IOUT = 0 mA -25 0 25 50 75 100 125 150 Junction Temperature (_C) Output Voltage (%) IOUT = 200 mA IOUT = 300 mA 0.30 0.15 0.00 -0.15 -0.30 -0.45 -0.60 -0.75 0 50 100 150 200 250 300 350 Load Current (mA)
Normalized Output Voltage vs. Load Current
0.6 0.4 0.2
Normalized VOUT vs. Temperature
180 160 140 Dropout Voltage (mV) 120 100 80 60 40 20 0 2.0
Dropout Voltage vs. VOUT
-0.0 V OUT (%) -0.2 -0.4 -0.6 -0.8 -1.0 -1.2 -1.4 -1.6 -40 -20 0 20 40 60 80 100 120 IOUT = 300 mA IOUT = 100 mA IOUT = 0 mA
IOUT = 300 mA
IOUT = 200 mA
IOUT = 10 mA 2.5 3.0 3.5 VOUT 4.0 4.5 5.0
140
Junction Temperature (_C)
No Load Current vs. Input Voltage
250 1500
GND Pin Current vs. Temperature and Load
200
1200
I GND ( mA)
150 85_C 100 25_C -40_C
I GND ( mA)
900 IOUT = 300 mA 600 IOUT = 200 mA 300 IOUT = 0 mA
50
0 0 1 2 3 4 5 6 7 Input Voltage (V) www.vishay.com
0 -40
-20
0
20
40
60
80
100
120
140
Junction Temperature (_C) Document Number: 71614 S-51147-Rev. E, 20-Jun-05
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Si91821
Vishay Siliconix
TYPICAL WAVEFORMS
Load Transient Response-1 Load Transient Response-2
VOUT 10 mV/div VOUT 10 mV/div ILOAD 100 mA/div ILOAD 100 mA/div
5.00 ms/div
VOUT = 2.775 V COUT = 2.2 mF ILOAD = 1 to 150 mA trise = 2 msec
5.00 ms/div
VOUT = 2.775 V COUT = 2.2 mF ILOAD = 150 to 1 mA tfall = 2 msec
Load Transient Response-3
Load Transient Response-4
VOUT 10 mV/div VOUT 10 mV/div ILOAD 100 mA/div ILOAD 100 mA/div
5.00 ms/div
VOUT = 2.775 V COUT = 1.0 mF ILOAD = 1 to 150 mA trise = 2 msec
5.00 ms/div
VOUT = 2.775 V COUT = 1.0 mF ILOAD = 150 to 1 mA tfall = 2 msec
LineTransient Response-1
VOUT 2 V/div VIN 2 V/div
LineTransient Respons-2
VOUT 10 mV/div
VOUT 10 mV/div
20 ms/div
VINSTEP = 4.77 to 5.77 V VOUT = 2.775 V COUT = 2.2 mF CIN = 2.2 mF ILOAD = 300 mA trise = 5 msec
20 ms/div
VINSTEP = 5.77 to 4.77 V VOUT = 2.775 V COUT = 2.2 mF CIN = 2.2 mF ILOAD = 300 mA tfall = 5 msec www.vishay.com
Document Number: 71614 S-51147-Rev. E, 20-Jun-05
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Si91821
Vishay Siliconix
TYPICAL WAVEFORMS
Turn-On Sequence Turn-Off Sequence
VIN CH-3 2 V/div VIN 2 V/div VOUT 2 V/div VOUT CH-1 2 V/div
ERROR 2 V/div ERROR CH-2 2 V/div
100 ms/div
VIN = 4 V VOUT = 2.775 V CNOISE = 0.033 mF ILOAD = 300 mA
20 ms/div
VIN = 4 V VOUT = 2.775 V CNOISE = 0.033 mF ILOAD = 300 mA
Output Noise
20.0
Noise Spectrum
mV 200 mV/div
Hz
0.01 10 ms/div VIN = 3.80 V VOUT = 2.775 V IOUT = 300 mA CNOISE = 0.033 mF BW = 10 Hz to 1 MHz 10 Hz VIN = 3.80 V VOUT = 2.775 V/10 mA CNOISE = 0.033 mF 1 MHz
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?71614. www.vishay.com Document Number: 71614 S-51147-Rev. E, 20-Jun-05
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