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
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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
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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
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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
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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
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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
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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
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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
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APPLICATIO S I FOR ATIO
WU UU
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
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