LT6650

16650fa

APPLICATIO SU

FEATURES

TYPICAL APPLICATIO

U

DESCRIPTIO

U

The LT®6650 is a micropower, low voltage 400mV refer-ence. Operating with supplies from 1.4V up to 18V, thedevice draws only 5.6µA typical, making it ideal for lowvoltage systems as well as handheld instruments andindustrial control systems. With only two resistors theinternal buffer amplifier can scale the 400mV reference toany desired value up to the supply voltage.

The reference is postpackage-trimmed to increase theoutput accuracy. The output can sink and source 200µAover temperature. Quiescent power dissipation is 28µW.Stability is ensured with any output capacitor of 1µF orhigher.

The LT6650 is the lowest voltage series reference availablein the 5-lead SOT-23 package.

Battery-Operated Systems Handheld Instruments Industrial Control Systems Data Acquisition Systems Negative Voltage References

Low Quiescent Current 5.6µA (typical) Wide Supply Range: 1.4V to 18V 400mV Reference ±1% Maximum Accuracy Over

Temperature at 5V Rail-to-Rail Buffer Amplifier 0.5% 400mV Maximum Initial Accuracy at 5V Shunt Configurable Sinks and Sources Current Wide Operational Range –40°C to 125°C Externally Adjustable Output Voltage Low Profile 1mm 5-lead SOT-23

(ThinSOT™) Package

Micropower, 400mVReference with Rail-to-Rail Buffer Amplifier in SOT-23

OUTVOUT0.4V

VIN = 1.4V TO 18V

IQ ≈ 6µA

5

1FB

IN

4

GND

1µF2

LT6650

–

+

1µF

VR = 400mVREFERENCE

6650 TA01a

TEMPERATURE (°C)

REFE

RENC

E VO

LTAG

E (m

V)

402

401

400

398

399

–30 10 50 90

6650 TA01b

130–50 –10 30 70 110

TYPICAL LT6650 PARTVIN = 5V

SINK 200µA

SOURCE –200µA

NO LOAD

LT6650 Temperature DriftBattery-Powered 0.4V Reference

, LTC and LT are registered trademarks of Linear Technology Corporation.ThinSOT is a trademark of Linear Technology Corporation.All other trademarks are the property of their respective owners.

LT6650

26650fa

Total Supply Voltage (VIN to GND)........................... 20VFB Voltage (Note 2) ....................... 20V to (GND – 0.3V)Output Voltage (OUT) .................... 20V to (GND – 0.3V)Output Short-Circuit Duration .......................... IndefiniteFB Input Current ................................................... 10mAOperating Temperature Range ............... –40°C to 125°CSpecified Temperature Range

LT6650CS5 ............................................. 0°C to 70°CLT6650IS5 ........................................... –40°C to 85°CLT6650HS5 (Note 3) ......................... –40°C to 125°C

Maximum Junction Temperature .......................... 150°CStorage Temperature Range (Note 4) .... –65°C to 150°CLead Temperature (Soldering, 10 sec).................. 300°C

ORDER PART NUMBER

TJMAX = 150°C, θJA = 230°C/W

The temperature grades are identified by a label on the shipping container.Consult LTC Marketing for parts specified with wider operating temperature ranges.

ABSOLUTE AXI U RATI GS

W WW U

PACKAGE/ORDER I FOR ATIOU UW

(Note 1)TOP VIEW

S5 PACKAGE5-LEAD PLASTIC TSOT-23

1

2

3

FB

GND

DNC*

5

4

OUT

IN

*Do Not Connect

S5 PART MARKINGLBDVLBDVLBDV

LT6650CS5LT6650IS5LT6650HS5

ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operatingtemperature range, otherwise specifications are at TA = 25°C. VIN = 5V, CIN = 1µF, FB = OUT, no DC load, CL = 1µF, unlessotherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

VOUT Output Voltage (Notes 4, 5) LT6650 398 400 402 mV–0.5 0.5 %

LT6650CS5 397 400 403 mV –0.75 0.75 %

LT6650IS5 396 400 404 mV –1 1 %

LT6650HS5 394 400 406 mV –1.5 1.5 %

VIN Operating Input Voltage 1.4 18 V

∆VOUT/∆VIN Line Regulation 1.4V ≤ VIN ≤ 18V1 6 mV

150 900 ppm/V

LT6650CS5, LT6650IS5 7.5 mV 1130 ppm/V

LT6650HS5 8.5 mV 1280 ppm/V

∆VOUT/∆IOUT Load Regulation (Note 6) Sourcing from 0µA to –200µA –0.04 –0.2 mV500 2500 ppm/mA

–0.4 mV 5000 ppm/mA

Sinking from 0µA to 200µA 0.24 1 mV3000 12500 ppm/mA

2 mV 20000 ppm/mA

Order Options Tape and Reel: Add #TRLead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBFLead Free Part Marking: http://www.linear.com/leadfree/

LT6650

36650fa

TC Output Voltage Temperature 30 ppm/°CCoefficient (Note 10)

∆VDO Dropout Voltage (Note 7) Referred to VIN = 1.8V, VOUT = 1.4V(RF = 100k, RG = 39.2k)∆VOUT = –0.1%, IOUT = 0µA 75 100 mV

150 mV

∆VOUT = –0.1%, IOUT = –200µA Sourcing 165 250 mV 350 mV

∆VOUT = –0.1%, IOUT = 200µA Sinking (Note 11) –300 –150 mV 0 mV

ISC Short-Circuit Output Current VOUT Shorted to GND 5 mAVOUT Shorted to VIN 9 mA

IIN Supply Current 5.6 11 µA 14 µA

VIN = 18V 5.9 12 µA 15 µA

IFB FB Pin Input Current VFB = VOUT = 400mV1.2 10 nA

LT6650CS5, LT6650IS5 15 nALT6650HS5 30 nA

TON Turn-On Time CLOAD = 1µF 0.5 ms

en Output Noise (Note 8) 0.1Hz ≤ ƒ ≤ 10Hz 20 µVP-P10Hz ≤ ƒ ≤ 1KHz, IOUT = –200µA Sourcing 23 µVRMS

VHYS Hysteresis (Note 9) ∆T = 0°C to 70°C 0.1 mV 250 ppm

∆T = –40°C to 85°C 0.24 mV 600 ppm

Note 1: Absolute Maximum Ratings are those values beyond which the lifeof a device may be impaired.Note 2: The FB pin is protected by an ESD diode to the ground. If the FBinput voltage exceeds –0.3V below ground, the FB input current should belimited to less than 10mA. If the FB input voltage is greater than 5V, the FBinput current is expected to meet specified performance from TypicalPerformance Characteristics but is not tested or QA sampled at thisvoltage.Note 3: If the part is operating at temperatures above 85°C, it isrecommended to enhance the stability margin by using an outputcapacitor greater than 10µF or a series RC combination having a 100µsequivalent time constant. See Application section for details.Note 4: If the part is stored outside of the specified temperature range, theoutput voltage may shift due to hysteresis.Note 5: ESD (Electrostatic Discharge) sensitive devices. Extensive use ofESD protection devices are used internal to the LT6650; however, highelectrostatic discharge can damage or degrade the device. Use proper ESDhandling precautions.

ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operatingtemperature range, otherwise specifications are at TA = 25°C. VIN = 5V, CIN = 1µF, FB = OUT, no DC load, CL = 1µF, unlessotherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

Note 6: Load regulation is measured on a pulse basis from no load to thespecified load current. Output changes due to die temperature changemust be taken into account separately.Note 7: Dropout Voltage is (VIN – VOUT) when VOUT falls to 0.1% below itsnominal value at VIN = 1.8V.Note 8: Peak-to-Peak noise is measured with a single pole highpass filterat 0.1Hz and a 2-pole lowpass filter at 10Hz. The unit is enclosed in a stillair environment to eliminate thermocouple effects on the leads. The testtime is 10 seconds.Note 9: Hysteresis in the output voltage is created by package stress thatdiffers depending on whether the IC was previously at a higher or lowertemperature. Output voltage is always measured at 25°C, but the IC iscycled to 85°C or –40°C before a successive measurement. Hysteresis isroughly proportional to the square of the temperature change.Note 10: Temperature coefficient is measured by dividing the change inoutput voltage by the specified temperature range.Note 11: This feature guarantees the shunt mode operation of the device.

LT6650

46650fa

INPUT VOLTAGE (V)0

SUPP

LY C

URRE

NT (µ

A)

6

8

10

16

6650 G03

4

2

04 8 12 20142 6 10 18

125°C

–55°C

25°C

TEMPERATURE (°C)–60

OUTP

UT V

OLTA

GE (m

V)

404

403

402

400

401

399

398

397

396100

6650 G01

–20–40 0 40 80 12020 60

TYPICAL PART

VIN = 1.4V

VIN = 5VVIN = 18V

TEMPERATURE (°C)–60

OUTP

UT V

OLTA

GE (m

V)

403

402

400

401

399

398100

6650 G02

–20–40 0 40 80 12020 60

THREE PARTSVIN = 5V

INPUT VOLTAGE (V)0

SUPP

LY C

URRE

NT (µ

A)

6

8

10

1.6

6650 G04

4

2

00.4 0.8 1.2 2.01.40.2 0.6 1.0 1.8

125°C

–55°C

25°C

INPUT VOLTAGE (V)2

398

OUTP

UT V

OLTA

GE (m

V)

399

400

401

402

6 10 14 18

6550 G05

403

404

4 8 12 16

TA = 125°C

TA = –55°C

TA = 25°C

INPUT VOLTAGE (V)0.8

398

OUTP

UT V

OLTA

GE (m

V)

399

400

401

402

1.2 1.6 2.01.8

6650 G06

403

404

1.0 1.4

TA = 125°C

TA = –55°C

TA = 25°C

OUTPUT CURRENT (µA)10

OUTP

UT V

OLTA

GE C

HANG

E (µ

V)

0

–10

–20

–30

–40

–50

–60

–70

–80

–90

–100100 1000

6650 G07

TYPICAL PARTVIN = 5V

125°C

–55°C

25°C

OUTPUT CURRENT (µA)10

OUTP

UT V

OLTA

GE C

HANG

E (µ

V)

1000

900

800

700

600

500

400

300

200

100

0100 1000

6650 G08

TYPICAL PARTVIN = 5V

125°C

–55°C

25°C

OUTPUT CURRENT (µA)10

INPU

T-OU

TPUT

VOL

TAGE

(mV)

500

400

300

200

100

0100 1000

6650 G09

VOUT = 1.425V - TYP (RF = 100k, RG = 39.2k)0.1% VOUT

125°C

–55°C

25°C

Output Voltage TemperatureDrift

Output Voltage TemperatureDrift

Supply Current vs Input Voltage Line Regulation Line Regulation

Load Regulation (Sourcing) Load Regulation (Sinking)Minimum Input-Output VoltageDifferential (Sourcing)

TYPICAL PERFOR A CE CHARACTERISTICS

UW

(See Applications, Figure 1)

Supply Current vs Input Voltage

LT6650

56650fa

Minimum Input-Output VoltageDifferential (Sinking)

Output Short-Circuit Current vsInput Voltage

Output Short-Circuit Current vsInput Voltage

FB Pin Current vs FB Pin Voltage FB Pin Current vs FB Pin Voltage Gain and Phase vs Frequency

Output Noise 0.1Hz to 10Hz Output Voltage Noise Spectrum Integrated Noise 10Hz to 1kHz

OUTPUT CURRENT(µA)10 100 1000

INPU

T-OU

TPUT

VOL

TAGE

(mV)

0

–400

–300

–200

–100

–500

6650 G10

VOUT = 1.425V - TYP (RF = 100k, RG = 39.2k)0.1% VOUT

125°C

–55°C

25°C

INPUT VOLTAGE (V)0

OUTP

UT C

URRE

NT (m

A)6

8

14

12

10

16

6650 G11

4

24 8 12 20142 6 10 18

OUTPUT SHORTED TO GND

125°C

–55°C

25°C

INPUT VOLTAGE (V)0

OUTP

UT C

URRE

NT (m

A)

6

8

14

12

10

16

6650 G12

4

24 8 12 20142 6 10 18

OUTPUT SHORTED TO VIN

125°C25°C

–55°C

FB PIN VOLTAGE (V)–0.6

–10

FB P

IN C

URRE

NT (n

A)

0

2

4

6

–0.2 0.2 0.6 1.0

6650 G13

8

–2

–4

–6

–8

10

–0.4 0 0.4 0.8

125°C

VFB ≠ VOUTCURRENT IS POSITIVE WHENIT ENTERS THE DEVICE

–55°C

25°C

FB PIN VOLTAGE (V)1 3 7 95 151311 17 19

FB P

IN C

URRE

NT (n

A)

10

1

0.1

0.01

6650 G14

125°C

VFB ≠ VOUTCURRENT IS POSITIVE WHENIT ENTERS THE DEVICE

–55°C

25°C

FREQUENCY (kHz)

GAIN

(dB)

120

100

80

60

40

20

0 0

–20

–40

PHASE (DEG)

120

100

80

60

40

20

–20

–400.01 1 10 100

6650 G15

0.1

TA = 25°CUNITY GAINRL = 2kCL = 1µF

GAIN PHASE

TIME (s)0

OUTP

UT N

OISE

(5µV

/DIV

)

8

6650 G16

2 4 6 1071 3 5 9

VIN = 5V

FREQUENCY (Hz)10

NOIS

E LE

VEL

(µV/

√Hz)

20

100 1k 10k

6650 G17

VIN = 5VCL = 1µF

IOUT = –40µA

IOUT = 0µA

0

5

10

15

IOUT = –200µA

FREQUENCY (Hz)10

1

INTE

GRAT

ED N

OISE

(µV R

MS)

10

100

100 1k

6650 G18

VIN = 5VCL = 1µFIOUT = –200µA

TYPICAL PERFOR A CE CHARACTERISTICS

UW

(See Applications, Figure 1)

LT6650

66650fa

TYPICAL PERFOR A CE CHARACTERISTICS

UW

Output Impedance vs Frequency Output Impedance vs Frequency Output Impedance vs Frequency

Power Supply Rejection Ratio vsFrequency

Power Supply Rejection Ratio vsFrequency

Power Supply Rejection Ratio vsFrequency

Power Supply Rejection Ratio vsFrequency

Power Supply Rejection Ratio vsFrequency

Power Supply Rejection Ratio vsFrequency

FREQUENCY (Hz)

10

OUTP

UT IM

PEDA

NCE

(Ω)

100

10 1k 10k 100k

6650 G19

1100

1000

CL = 1µF

CL = 10µF

CL = 47µF

IOUT = 0µARZ = 0Ω

FREQUENCY (Hz)

10OU

TPUT

IMPE

DANC

E (Ω

)

100

10 1k 10k 100k

6650 G20

1100

1000

CL = 1µFCL = 10µF

CL = 47µF

IOUT = –40µARZ = 0Ω

FREQUENCY (Hz)

10

OUTP

UT IM

PEDA

NCE

(Ω)

100

10 1k 10k 100k

6650 G21

1100

1000

CL = 1µF

CL = 10µF

CL = 47µF

IOUT = 0µACL • RZ = 100µs

FREQUENCY (Hz)

POW

ER S

UPPL

Y RE

JECT

ION

RATI

O (d

B)

20

10

0

–10

–20

–30

–40

–50

–60

–70

–8010 1k 10k 100k

6650 G22

100

CL = 1µFCL = 10µF

CL = 47µF

IOUT = 0µARZ = 0Ω

FREQUENCY (Hz)

POW

ER S

UPPL

Y RE

JECT

ION

RATI

O (d

B)

20

10

0

–10

–20

–30

–40

–50

–60

–70

–8010 1k 10k 100k

6650 G23

100

CL = 1µFCL = 10µF

CL = 47µF

IOUT = –40µARZ = 0Ω

FREQUENCY (Hz)

POW

ER S

UPPL

Y RE

JECT

ION

RATI

O (d

B)

20

10

0

–10

–20

–30

–40

–50

–60

–70

–8010 1k 10k 100k

6650 G24

100

CL = 1µF

CL = 10µF

CL = 47µF

IOUT = 0µACL • RZ = 100µs

FREQUENCY (Hz)

POW

ER S

UPPL

Y RE

JECT

ION

RATI

O (d

B)

20

10

0

–10

–20

–30

–40

–50

–60

–70

–8010 1k 10k 100k

6650 G25

100

CL = 1µFCL = 10µF

CL = 47µF

IOUT = 0µARZ = 0ΩCIN = 1µF RIN = 1k

FREQUENCY (Hz)

POW

ER S

UPPL

Y RE

JECT

ION

RATI

O (d

B)

20

10

0

–10

–20

–30

–40

–50

–60

–70

–8010 1k 10k 100k

6650 G26

100

CL = 1µF

CL = 10µF

CL = 47µF

IOUT = –40µARZ = 0ΩCIN = 1µF RIN = 1k

FREQUENCY (Hz)

POW

ER S

UPPL

Y RE

JECT

ION

RATI

O (d

B)

20

10

0

–10

–20

–30

–40

–50

–60

–70

–8010 1k 10k 100k

6650 G27

100

CL = 1µFCL = 10µF

CL = 47µF

IOUT = 0µACL • RZ = 100µsCIN = 1µF RIN = 1k

(See Applications, Figure 1)

LT6650

76650fa

APPLICATIO S I FOR ATIO

WU UU

PI FU CTIO S

UUU

BLOCK DIAGRA

W

FB (Pin 1): Resistor Divider Feedback Pin. Connect aresistor divider from OUT to GND and the center tap to FB.This pin sets the output potential.

GND (Pin 2): Ground Connection.

DNC (Pin 3): Do not connect. Connected internally for postpackage trim. This pin must be left unconnected.

IN (Pin 4): Positive Supply. Bypassing with a 1µF capacitoris recommended if the output loading changes.

OUT (Pin 5): Reference Output. The output sources andsinks current. It is stable with any load capacitor with atotal capacitance of 1µF or more. Higher load capacitanceimproves load transient response.

OUT

DNC

FB

IN

GND

LT6650

–

+VR = 400mVREFERENCE

6650 BD

4

2

3

5

1

Long Battery Life

The LT6650 is a micropower, adjustable reference whichoperates from supply voltages ranging from 1.4V to 18V.The series regulated output may be configured with exter-nal resistors to any voltage from 400mV to nearly thesupply potential. Under no-load conditions, the LT6650dissipates only 8µW when operating on a 1.4V supply.Other operating configurations allow the LT6650 to beused as a micropower positive or negative adjustableshunt reference from 1.4V to 18V.

Bypass and Load Capacitor

The LT6650 voltage reference requires a 1µF or greateroutput capacitance for proper operation. This capacitancemay be provided by either a single capacitor connectedbetween OUT and GND or formed by the aggregate ofseveral capacitors that may be serving other decoupling

functions. Output impedance can be reduced by DC load-ing of the output by 40µA to 200µA, and/or adding an RZto the output capacitor for a 100µs time constant as shownin Figure 1 and the Typical Performance Characteristicsgraphs.

The LT6650 Voltage reference should have an input by-pass capacitor of 0.1µF or larger. When the circuit is

Figure 1. LT6650 Input-Output Configuration

VOUTVINOUTINRIN

FB

GND

LT6650

6650 F012

4 5

1

CL

RZ

CIN

LT6650

86650fa

operated from a small battery or other relatively highimpedance source, a minimum 1µF capacitor is recom-mended. PSRR can be significantly enhanced by adding alow-pass RC filter on the input, with a time-constant of1ms or higher, as shown in Figure 1. The Typical Perfor-mance Characteristics graphs show performance as afunction of several combinations of input and outputcapacitance.

An input RC of 100ms or more is recommended (such as5k and 22µF) when output transients must be minimizedin the face of high supply noise, such as in automotiveapplications. Figure 2 shows an input filter structure thateffectively eliminates supply transients from affecting theoutput. With this extra input decoupling and the LT6650operating normally from a 12V bus, 50V transients induceless than <0.5% VOUT perturbations.

Figure 3 shows the turn-on response time for the circuit inFigure 1. The input voltage steps from 0V to 3V, and theoutput is configured to produce 400mV. Input bypass andoutput load capacitance are 1µF, RIN = 0Ω, RZ = 0Ω, andthe output settles in approximately 0.5ms. Figure 4 shows

APPLICATIO S I FOR ATIO

WU UU

Figure 2. High Noise-Immunity Input Network

Figure 3. LT6650 Turn-On Characteristic

Figure 4. Output Response to ±0.5V Input Step

Figure 5. Output Response to Bidirectional Load Step(100µA to –100µA)

Figure 6. Output Response to Current-Sourcing Load Step(–100µA to –200µA)

VIN

4.7k

NOISYPOWER BUS

6650 F02

22µF1N7515V

33k

1µF

the same circuit responding to input transients of 0.5V,settling in about 0.3ms. Figures 5 through 7 show thesame circuit responding to various load steps: changesbetween ±100µA in Figure 5; sourcing current step be-tween –100µA and –200µA in Figure 6; and sinking current

6650 F05

VOUT10mV/DIV

IOUT

SINKING

SOURCING

100µASINKING

100µASOURCING

6650 F06

VOUT10mV/DIV

AC

IOUT–100µA

–200µAVOUT

0.2ms/DIV 6650 F03

VIN3V

0V0.4V0V

2ms/DIV 6650 F04

VIN

VOUT

3V

2.5V

0.4V0V

LT6650

96650fa

Figure 9. Typical Configuration of LT6650 as Adjustable PositiveShunt Reference

Figure 10. Typical Configuration of LT6650 as AdjustableNegative Shunt Reference

APPLICATIO S I FOR ATIO

WU UU

step between 100µA and 200µA in Figure 7. Load step settlingoccurs in about 0.5ms or less (to ±0.2%).

Output Adjustment

If the LT6650 is to be used as a 400mV reference, then theoutput and feedback pins may be tied together without anyscale-setting components as shown in the front-pageapplication circuit. Setting the output to any higher voltageis a simple matter of selecting two feedback resistors toconfigure the non-inverting gain of the internal operationalamplifier, as shown in Figure 8. A feedback resistor RF isconnected between the OUT pin and the FB pin, and a gainresistor RG is connected from the FB pin to GND. Theresistor values are related to the output voltage by thefollowing relationship:

RF = RG • (VOUT – 0.4)/(0.4 – IFB • RG)

The IFB term represents the FB pin bias current, and cangenerally be neglected when RG is 100k or less. ForRG ≤ 20k, even worst-case IFB can be neglected (error

contribution <0.15%). Since the VOUT error distributionincreases at twice the resistor tolerance, high accuracyresistors or resistor networks are recommended. Theoutput voltage may be set to any level from 400mV up to350mV below the supply voltage with source or sinkcapability.

Noise Reduction Capacitor

In applications involving the use of resistive feedback forreference scaling, the intrinsic reference noise is amplifiedalong with the DC level. To minimize noise amplification,the use of a 1nF feedback capacitor is recommended, asshown in Figure 8 and other circuits with scaling resistors.

Shunt Reference Operation

The circuits shown in Figure 9 and Figure 10 form adjust-able shunt references. Along with the external bias resistorRB, the LT6650 provides positive or negative referenceoperation for outputs between 1.4V and 18V (positive ornegative). Just like a Zener diode, a supply VS is required,somewhat higher in magnitude than the desired reference

VOUT

6650 F09

10µF

OUTIN

FB

GND

LT6650

2

4 5

1

VS

RF

RB

RG

1nF

VOUT = 0.4V • (1 + RF/RG)

VOUT

6650 F10

10µF

OUTIN

FB

GND

LT6650

2

4 5

1RF

–VS

RB

RG

1nF

VOUT = –0.4V • (1 + RF/RG)

Figure 8. Typical Configuration for Output VoltagesGreater than 0.4V

VOUT

6650 F08

1µF1µF

1nF

OUTIN

FB

GND

LT6650

2

4 5

1

VS

1k

RF

RG

VOUT = 0.4V • (1 + RF/RG)

Figure 7. Output Response to Current-Sinking Load Step(100µA to 200µA)

6650 F07

VOUT10mV/DIV

AC

IOUT

200µA

100µA

LT6650

106650fa

APPLICATIO S I FOR ATIO

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Figure 11. Worst-Case 0°C to 70°C Hysteresis Figure 12. Worst-Case –40°C to 85°C Hysteresis

VOUT. RB must be within the following range for properoperation (the optimal value depends greatly on the direc-tion and magnitude of the load current):

RB > |VS – VOUT|/(200µA + 0.4/RG)

RB < |VS – VOUT|/(15µA + 0.4/RG)

Hysteresis

Due to various mechanical stress mechanisms inherent tointegrated-circuit packaging, internal offsets may not pre-cisely recover from variations that occur over tempera-ture, and this effect is referred to as hysteresis. Proprietarymanufacturing steps minimize this hysteresis, thoughsome small residual error can occur. Hysteresis measure-ments for the LT6650 can be seen in Figures 11 and 12.Figure 11 presents the worst-case data taken on partssubjected to thermal cycling between 0°C to 70°C, whileFigure 12 shows data for –40°C to 85°C cycling. Unitswere cycled several times over these temperature rangesand the largest changes are shown. As would be expected,

the parts cycled over the higher temperature extremesexhibit a broader hysteresis distribution. The worst hys-teresis measurements indicate voltage shifts of less than1000ppm (0.1%) from their initial value.

Limits of Operation

The LT6650 is a robust bipolar technology part. ESDclamp diodes are integrated into the design and aredepicted in the Simplified Schematic for reference. Diodesare included between the GND pin and the IN, OUT, and FBpins to prevent reverse voltage stress on the device.Unusual modes of operation that forward-bias any thesediodes should limit current to 10mA to avoid permanentdamage to the device. The LT6650 is fabricated using arelatively high-voltage process, allowing any pin to inde-pendently operate at up to 20V with respect to GND. Thepart does not include any over voltage protection mecha-nisms; therefore caution should be exercised to avoidinadvertent application of higher voltages in circuits in-volving high potentials.

DISTRIBUTION (ppm)–400

NUM

BER

OF U

NITS

2

3

6

5

4

400

6650 F11

1

0–200 0 200 600

LIGHT COLUMNS 0°C TO 25°CDARK COLUMNS 70°C TO 25°C

DISTRIBUTION (ppm)–1000

NUM

BER

OF U

NITS

2

3

6

5

4

500

6650 F12

7

1

0–500 1000250–750 –250 0 750

LIGHT COLUMNS –40°C TO 25°CDARK COLUMNS 85°C TO 25°C

LT6650

116650fa

PACKAGE DESCRIPTIO

U

SCHE ATIC WW

SI PLIFIED

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

1.50 – 1.75(NOTE 4)2.80 BSC

0.30 – 0.45 TYP 5 PLCS (NOTE 3)

DATUM ‘A’

0.09 – 0.20(NOTE 3) S5 TSOT-23 0302 REV B

PIN ONE

2.90 BSC(NOTE 4)

0.95 BSC

1.90 BSC

0.80 – 0.90

1.00 MAX0.01 – 0.100.20 BSC

0.30 – 0.50 REF

NOTE:1. DIMENSIONS ARE IN MILLIMETERS2. DRAWING NOT TO SCALE3. DIMENSIONS ARE INCLUSIVE OF PLATING4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR5. MOLD FLASH SHALL NOT EXCEED 0.254mm6. JEDEC PACKAGE REFERENCE IS MO-193

3.85 MAX

0.62MAX

0.95REF

RECOMMENDED SOLDER PAD LAYOUTPER IPC CALCULATOR

1.4 MIN2.62 REF

1.22 REF

S5 Package5-Lead Plastic TSOT-23

(Reference LTC DWG # 05-08-1635 Rev B)

IN

FB

GND

OUT

6650 SS

4

5

2

1

IN

ININ

LT6650

126650fa

Linear Technology Corporation1630 McCarthy Blvd., Milpitas, CA 95035-7417(408) 432-1900 FAX: (408) 434-0507 www.linear.com © LINEAR TECHNOLOGY CORPORATION 2003

LT/LT 1005 • PRINTED IN USA

RELATED PARTS

TYPICAL APPLICATIO

U

PART NUMBER DESCRIPTION COMMENTS

LT1790 Micropower LDO Precision Reference 0.05% Max Sources/Sinks-Current Available in SOT-23

LT1460 Micropower Precision Reference 0.075% Max 10ppm/ºC Available in SOT-23

LT1461 Micropower LDO Low TC Precision Reference 0.04% Max 3ppm/ºC 35µA Supply Current

LT1494/LT1495/ Single/Dual/Quad Micropower Op Amps 1.5µA, VOS < 375µV, IB < 1000pALT1496

LTC1540 Nanopower Comparator with Reference 300nA, Available in 3mm × 3mm DFN Package

LTC1798 Micropower LDO Reference 0.15% Max 6.5µA Supply Current

LT6700 Micropower Dual Comparator with Reference 6.5µA, Choice of Polarities Available in SOT-23

ANODE

CATHODE

ANODE

CATHODE

6650 TA02

10µF 1.4V ≤ VZ ≤ 18V30µA ≤ IZ ≤ 220µAVZ = 0.4V • (1 + RF/RG)

=OUTIN

FB

GND

LT6650

2

4 5

1RF

RG

1nF

Adjustable Micropower “Zener” 2-Terminal Reference