SI91821DH-277-T1 - VISHAY SILICONIX

Available

Si91821

Vishay Siliconix

Document Number: 71614

S-51147–Rev. E, 20-Jun-05

www.vishay.com

Micropower 300-mA CMOS LDO Regulator With Error Flag

FEATURES

DInput Voltage: 2.35−6.0 V

DFixed 1.8-V, 2.5-V, 2.8-V, 3.0-V, 3.3-V, 5.0-V, or

Adjustable Output Voltage Options

DLow 120-mV Dropout at 300-mA Load

DGuaranteed 300-mA Output Current

D500-mA Peak Output Current Capability

DUses Low ESR Ceramic Output Capacitor

DFast Load and Line Transient Response

DOnly 100-mV(rms) Noise With Noise Bypass

Capacitor

D1-mA Maximum Shutdown Current

DBuilt-in Short Circuit and Thermal Protection

DOut-Of-Regulation Error Flag (Power_Good)

APPLICATIONS

DCellular Phones

DLaptop and Palm Computers

DPDA, 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

Figure 3. Fixed Output, Low Noise, Full Features Application

CNOISE

ERROR

21, 4

GND

SET

VIN VOUT

GND

VIN

2.2 mF

Si91821

ON/OFF

2.2 mF

VOUT

POWER_GOOD

1 MW

0.033 mF

Figure 1. Fixed Output Figure 2.. Adjustable Output

VOUT

CNOISE

ERROR

2 1, 4

GND

SET

VIN VOUT

GND

VIN

2.2 mF

Si91821

2.2 mF

Optional

VOUT

CNOISE

ERROR

2 1, 4

GND

SET

VIN VOUT

GND

VIN

2.2 mF

Si91821

2.2 mF

Si91821

Vishay Siliconix

www.vishay.com

2Document Number: 71614

S-51147–Rev. E, 20-Jun-05

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 MSOPb666 mW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Thermal Impedance (QJA)a

8-Pin MSOPb185_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)

COUTRange = 1 mF to 10 mF ("10%, x5R or x7R type)

CIN w COUT

SPECIFICATIONS

Test Conditions

Unless Otherwise Specified

V V 1 V I 1 A

Limits

−40 to 85_C

Parameter Symbol VIN = VOUT(nom) + 1 V, IOUT = 1 mA

CIN = 2.2 mF, COUT = 2.2 mF, VSD = 1.5 V TempaMinbTypcMaxbUnit

Input Voltage VIN 2.35 6.0

Output Voltage VOUT Adjustable Version Full 1.5 5.0 V

Out

ut Volta

e Accurac

VOUT

1 mA v IOUT v 300 mA

Room −1.5 1.5 %

Output Voltage Accuracy

(to stated output voltage) VOUT 1 mA v IOUT v 300 mA Full −2.5 2.5

VOUT(nom)

Feedback Voltage (ADJ Version)

VSET

Room 1.191 1.215 1.239

Feedback Voltage (ADJ Version) VSET Full 1.179 1.251 V

Line Regulation

(Except 5-V Version)

DV100

From VIN = VOUT(nom) + 1 V

to VOUT(nom) + 2 V Full −0.18 0.18

Line Regulation (5-V Version) DVOUT 100

V V

From VIN = 5.5 V to 6 V Full −0.18 0.18 %/V

Line Regulation (ADJ Version)

VIN VOUT(nom) VOUT = 1.5 V From VIN = 2.5 V to 3.5 V Full −0.18 0.18

%/V

Line Regulation (ADJ Version) VOUT = 5 V From VIN = 5.5 V to 6 V Full −0.18 0.18

IOUT = 10 mA Room 5 20

Dropout VoltagedVIN − VOUT IOUT = 200 mA Full 80 135 mV

IN OUT

IOUT = 300 mA Full 120 200

IOUT = 0 mA Full 150 270

Ground Pin Current IGND IOUT = 200 mA Room 500

GND

IOUT = 300 mA Room 600 mA

Shutdown Supply Current IIN(off) VSD = 0 V Room 0.1 1

Peak Output Current IO(peak) VOUT w 0.95 x VOUT(nom), tpw = 2 ms Room 500 mA

BW = 10 Hz to 100 kHz w/o CNOISE Room 260

Out

ut Noise Volta

e e

BW = 10 Hz to 100 kHz

IOUT = 150 mA CNOISE = 0.1 mF Room 37

(

rms

)

Output Noise Voltage

BW = 10 to 100 kHz

IOUT = 10 mA CNOISE = 33 nF Room 54

mV (rms)

f = 1 kHz Room 60

Ripple Rejection DVOUT/DVIN IOUT = 150 mA f = 10 kHz Room 50 dB

pp j

OUT IN

OUT

f = 100 kHz Room 40

Si91821

Vishay Siliconix

Document Number: 71614

S-51147–Rev. E, 20-Jun-05

www.vishay.com

SPECIFICATIONS

Limits

−40 to 85_C

Test Conditions

Unless Otherwise Specified

VIN = VOUT(nom) + 1 V, IOUT = 1 mA

CIN = 2.2 mF, COUT = 2.2 mF, VSD = 1.5 V

Parameter UnitMaxb

Typc

Minb

Tempa

Test Conditions

Unless Otherwise Specified

VIN = VOUT(nom) + 1 V, IOUT = 1 mA

CIN = 2.2 mF, COUT = 2.2 mF, VSD = 1.5 V

Symbol

Dynamic Line Regulation DVO(line) VIN : VOUT(nom) + 1 V to VOUT(nom) + 2 V

tr/tf = 5 ms, IOUT = 250 mA Room 10

Dynamic Load Regulation DVO(load) IOUT : 1 mA to 150 mA, tr/tf = 2 ms Room 30

Turn-on Overshoot DVOOS VIN followed by SD = High Event

CNOISE v 100 nF Room 2.5 %

VOUT Turn-On-Time tON COUT = 10 mF, VOUT to 90% of final value,

VIN = 3.6 V Room 350 mS

Thermal Shutdown

Thermal Shutdown Junction Temp TJ(s/d) Room 165

Thermal Hysteresis THYST Room 20

Short Circuit Current ISC VOUT = 0 V Room 800 mA

Shutdown Input

SD Input Voltage

VIH High = Regulator ON (Rising) Full 1.5 VIN

SD Input Voltage VIL Low = Regulator OFF (Falling) Full 0.4 V

SD Input Currente

IIH VSD = 0 V, Regulator OFF Room 0.01

SD Input Currente

IIL VSD = 6 V, Regulator ON Room 1.0 mA

Shutdown Hysteresis VHYST Full 100 mV

Error Output

Output High Leakage IOFF ERROR = VOUT(nom) Full 0.01 2 mA

Output Low Voltage VOL ISINK = 2 mA Full 0.4

Power_Good Trip Threshold f, g

(Rising) VTH Full 0.93 x

VOUT

0.95 x

VOUT

0.97 x

VOUT V

HysteresisfVHYST Room 2% x

VOUT

Error Delay tDELAY CNOISE v 100 nF Full 10 mS

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.

Si91821

Vishay Siliconix

www.vishay.com

4Document Number: 71614

S-51147–Rev. E, 20-Jun-05

TIMING WAVEFORMS

VOUT

ERROR

Figure 4. Timing Diagram for Power-Up

tON

tDELAY

VNOM = 0.95 VNOM

tDELAY

VIH

VIL

PIN CONFIGURATION

vOUT ERROR

GND CNOISE

VOUT SET

MSOP-8

Top View

vIN SD

PIN DESCRIPTION

Pin Number Name Function

1, 4 VOUT Output voltage. Connect COUT between this pin and ground.

2 VIN Input supply pin. Bypass this pin with a 2.2-mF ceramic or tantalum capacitor to ground.

3 GND Ground pin. Local ground for CNOISE and COUT

5 SET 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.

6 CNOISE Noise bypass pin. For low noise applications, a 0.01-mF or larger ceramic capacitor should be connected from this pin

to ground.

7 SD By applying less than 0.4 V to this pin, the device will be turned off. Connect this pin to VIN if unused.

8 ERROR This open drain output is an error flag output which goes low when VOUT drops 5% below its nominal voltage.

Si91821

Vishay Siliconix

Document Number: 71614

S-51147–Rev. E, 20-Jun-05

www.vishay.com

BLOCK DIAGRAM

−

CIN

2.2 mF

VIN

OFF

GND

RFB2

RFB1

SET

−

1.215 V

VREF −

NOISE

−

2 mA

To VIN 1, 4

COUT

2.2 mF

REXT

VOUT

ERROR

Figure 5. 300-mA CMOS LDO Regulator

6 MW60 mV

Switches shown for device in normal operating mode (SD = HIGH)

−

CIN

2.2 mF

VIN

OFF

GND

SET

−

1.215 V

VREF −

NOISE

−

2 mA

To VIN 1, 4

COUT

2.2 mF

REXT

VOUT

ERROR

Figure 6. 300-mA CMOS LDO Regulator (Adjustable Output)

6 MW60 mV

VSET

Si91821

Vishay Siliconix

www.vishay.com

6Document Number: 71614

S-51147–Rev. E, 20-Jun-05

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+

ǒVOUT *VSETǓR2

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.

Si91821

Vishay Siliconix

Document Number: 71614

S-51147–Rev. E, 20-Jun-05

www.vishay.com

ORDERING INFORMATION

Standard

Part Number Lead (Pb)-Free

Part Number Marking Voltage Temperature

Range Package

Si91821DH-18-T1 Si91821DH-18-T1—E3 1821

1800 1.80 V

Si91821DH-25-T1 Si91821DH-25-T1—E3 1821

2500 2.50 V

Si91821DH-28-T1 Si91821DH-28-T1—E3 1821

2800 2.80 V

Si91821DH-30-T1 Si91821DH-30-T1—E3 1821

3000 3.00 V −40 to 85_C MSOP-8

Si91821DH-33-T1 Si91821DH-33-T1—E3 1821

3300 3.30 V

Si91821DH-50-T1 Si91821DH-50-T1—E3 1821

5000 5.00 V

Si91821DH-AD-T1 Si91821DH-AD-T1—E3 1821

ADJ Adjustable

Eval Kit Temperature Range Board Type

Si91821DB −40 to 85_CSurface Mount

TYPICAL CHARACTERISTICS (INTERNALLY REGULATED, 25_C UNLESS NOTED)

100

150

200

250

0 100 200 300 400 500

Dropout V oltage vs. Load Current

ILOAD (mA)

(mV)VDROP

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0123456

Dropout Characteristic

VIN (V)

(V)VOUT

RLOAD = 16.5 W

VOUT = 2.775 V VOUT = 2.775 V

Si91821

Vishay Siliconix

www.vishay.com

8Document Number: 71614

S-51147–Rev. E, 20-Jun-05

TYPICAL CHARACTERISTICS (INTERNALLY REGULATED, 25_C UNLESS NOTED)

100

150

200

250

01234567

No Load Current vs. Input Voltage

Input Voltage (V)

120

150

180

−50 −25 0 25 50 75 100 125 150

Dropout Voltage vs. Temperature

300

600

900

1200

1500

−40 −20 0 20 40 60 80 100 120 140

GND Pin Current vs. Temperature and Load

Junction Temperature (_C)

−0.75

−0.60

−0.45

−0.30

−0.15

0.00

0.15

0.30

0 50 100 150 200 250 300 350

Normalized Output Voltage vs. Load Current

Output Voltage (%)

Load Current (mA)

(mV)VDROP

IOUT = 0 mA

IOUT = 300 mA

IOUT = 10 mA

IOUT = 200 mA

VOUT = 2.775 V

−1.6

−1.4

−1.2

−1.0

−0.8

−0.6

−0.4

−0.2

−0.0

0.2

0.4

0.6

−40 −20 0 20 40 60 80 100 120 140

Normalized VOUT vs. Temperature

Junction Temperature (_C)

100

120

140

160

180

2.0 2.5 3.0 3.5 4.0 4.5 5.0

Dropout Voltage vs. VOUT

(%)VOUT

IOUT = 0 mA

IOUT = 300 mA

IOUT = 100 mA

VOUT

Dropout Voltage (mV)(I GND mA)

(I GND mA)

IOUT = 0 mA

IOUT = 300 mA

IOUT = 200 mA

Junction Temperature (_C)

25_C

85_C

−40_C

IOUT = 10 mA

IOUT = 300 mA

IOUT = 200 mA

Si91821

Vishay Siliconix

Document Number: 71614

S-51147–Rev. E, 20-Jun-05

www.vishay.com

TYPICAL WAVEFORMS

Load Transient Response-1 Load Transient Response-2

VOUT = 2.775 V

COUT = 2.2 mF

ILOAD = 150 to 1 mA

tfall = 2 msec

ILOAD

100 mA/div

VOUT

10 mV/div

Load Transient Response-3

VOUT = 2.775 V

COUT = 1.0 mF

ILOAD = 1 to 150 mA

trise = 2 msec

Load Transient Response-4

VOUT = 2.775 V

COUT = 1.0 mF

ILOAD = 150 to 1 mA

tfall = 2 msec

5.00 ms/div

LineTransient Response-1

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

LineTransient Respons-2

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

5.00 ms/div

20 ms/div

ILOAD

100 mA/div

VOUT

10 mV/div

VOUT = 2.775 V

COUT = 2.2 mF

ILOAD = 1 to 150 mA

trise = 2 msec

5.00 ms/div

ILOAD

100 mA/div

VOUT

10 mV/div

ILOAD

100 mA/div

VOUT

10 mV/div

VOUT

10 mV/div

VIN

2 V/div

VOUT

2 V/div

VOUT

10 mV/div

Si91821

Vishay Siliconix

www.vishay.com

10 Document Number: 71614

S-51147–Rev. E, 20-Jun-05

TYPICAL WAVEFORMS

VIN = 4 V

VOUT = 2.775 V

CNOISE = 0.033 mF

ILOAD = 300 mA

Turn-On Sequence

100 ms/div 20 ms/div

Output Noise

VIN = 3.80 V

VOUT = 2.775 V

IOUT = 300 mA

CNOISE = 0.033 mF

BW = 10 Hz to 1 MHz

Noise Spectrum

VIN = 3.80 V

VOUT = 2.775 V/10 mA

CNOISE = 0.033 mF

10 Hz

VIN = 4 V

VOUT = 2.775 V

CNOISE = 0.033 mF

ILOAD = 300 mA

Turn-Off Sequence

VIN

CH-3 2 V/div

VOUT

CH-1 2 V/div

ERROR

CH-2 2 V/div

10 ms/div

mVńHz

1 MHz

20.0

0.01

VIN 2 V/div

VOUT 2 V/div

ERROR 2 V/div

200 mV/div

Vishay Siliconix maintains worldwide manufacturing capability. Products may be manufactur ed at one of several qualified locations. Reliability data f or Silic on Te chnology a nd

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.