Datasheet

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LT6650

6650fa

APPLICATIO S

FEATURES

TYPICAL APPLICATIO

DESCRIPTIO

The LT

6650 is a micropower, low voltage 400mV refer-

ence. Operating with supplies from 1.4V up to 18V, the

device draws only 5.6µA typical, making it ideal for low

voltage systems as well as handheld instruments and

industrial control systems. With only two resistors the

internal buffer amplifier can scale the 400mV reference to

any desired value up to the supply voltage.

The reference is postpackage-trimmed to increase the

output accuracy. The output can sink and source 200µA

over temperature. Quiescent power dissipation is 28µW.

Stability is ensured with any output capacitor of 1µF or

higher.

The LT6650 is the lowest voltage series reference available

in the 5-lead SOT-23 package.

■

Battery-Operated Systems

■

Handheld Instruments

■

Industrial Control Systems

■

Data Acquisition Systems

■

Negative Voltage References

■

Low Quiescent Current 5.6

A (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, 400mV

Reference with Rail-to-Rail

Buffer Amplifier in SOT-23

OUT

0.4V

= 1.4V TO 18V

≈ 6µA

GND

1µF

LT6650

–

1µF

= 400mV

REFERENCE

6650 TA01a

TEMPERATURE (°C)

REFERENCE VOLTAGE (mV)

402

401

400

398

399

–30 10 50 90

6650 TA01b

130–50 –10 30 70 110

TYPICAL LT6650 PART

= 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.

Summary of content (12 pages)

PAGE 1
LT6650 Micropower, 400mV Reference with Rail-to-Rail Buffer Amplifier in SOT-23 U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 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.
PAGE 2
LT6650 U W W W ABSOLUTE AXI U RATI GS U W U PACKAGE/ORDER I FOR ATIO (Note 1) TOP VIEW Total Supply Voltage (VIN to GND)........................... 20V FB Voltage (Note 2) ....................... 20V to (GND – 0.3V) Output Voltage (OUT) .................... 20V to (GND – 0.3V) Output Short-Circuit Duration .......................... Indefinite FB Input Current ................................................... 10mA Operating Temperature Range ...............
PAGE 3
LT6650 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 5V, CIN = 1µF, FB = OUT, no DC load, CL = 1µF, unless otherwise noted. SYMBOL PARAMETER TC Output Voltage Temperature Coefficient (Note 10) ∆VDO Dropout Voltage (Note 7) CONDITIONS MIN ● Referred to VIN = 1.8V, VOUT = 1.4V (RF = 100k, RG = 39.2k) ∆VOUT = –0.
PAGE 4
LT6650 U W TYPICAL PERFOR A CE CHARACTERISTICS Output Voltage Temperature Drift 404 (See Applications, Figure 1) Output Voltage Temperature Drift 403 TYPICAL PART Supply Current vs Input Voltage 10 THREE PARTS VIN = 5V 403 8 OUTPUT VOLTAGE (mV) OUTPUT VOLTAGE (mV) 401 VIN = 1.
PAGE 5
LT6650 U W TYPICAL PERFOR A CE CHARACTERISTICS Minimum Input-Output Voltage Differential (Sinking) Output Short-Circuit Current vs Input Voltage 14 VOUT = 1.425V - TYP (RF = 100k, RG = 39.2k) 0.
PAGE 6
LT6650 U W TYPICAL PERFOR A CE CHARACTERISTICS IOUT = 0µA RZ = 0Ω CL = 10µF 100 OUTPUT IMPEDANCE (Ω) CL = 1µF 10 CL = 47µF 1 IOUT = –40µA RZ = 0Ω 100 CL = 10µF CL = 1µF CL = 47µF 10 1 100 1k 10k FREQUENCY (Hz) 100k 100 1k 10k FREQUENCY (Hz) 6650 G19 POWER SUPPLY REJECTION RATIO (dB) POWER SUPPLY REJECTION RATIO (dB) CL = 10µF CL = 1µF –20 –30 –40 –50 CL = 47µF –60 –70 –80 100 1k 10k FREQUENCY (Hz) IOUT = –40µA 10 RZ = 0Ω 0 CL = 10µF CL = 1µF –10 CL = 47µF –20 –30 –40 –50 –60 –7
PAGE 7
LT6650 U U U PI FU CTIO S FB (Pin 1): Resistor Divider Feedback Pin. Connect a resistor 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 post package trim. This pin must be left unconnected. IN (Pin 4): Positive Supply. Bypassing with a 1µF capacitor is recommended if the output loading changes. OUT (Pin 5): Reference Output. The output sources and sinks current.
PAGE 8
LT6650 U U W U APPLICATIO S I FOR ATIO operated from a small battery or other relatively high impedance source, a minimum 1µF capacitor is recommended. PSRR can be significantly enhanced by adding a low-pass RC filter on the input, with a time-constant of 1ms or higher, as shown in Figure 1. The Typical Performance Characteristics graphs show performance as a function of several combinations of input and output capacitance. the same circuit responding to input transients of 0.5V, settling in about 0.
PAGE 9
LT6650 U U W U APPLICATIO S I FOR ATIO step between 100µA and 200µA in Figure 7. Load step settling occurs in about 0.5ms or less (to ±0.2%). Output Adjustment If the LT6650 is to be used as a 400mV reference, then the output and feedback pins may be tied together without any scale-setting components as shown in the front-page application circuit.
PAGE 10
LT6650 U W U U APPLICATIO S I FOR ATIO VOUT. RB must be within the following range for proper operation (the optimal value depends greatly on the direction and magnitude of the load current): RB > |VS – VOUT|/(200µA + 0.4/RG) RB < |VS – VOUT|/(15µA + 0.
PAGE 11
LT6650 W W SI PLIFIED SCHE ATIC 4 IN IN IN 5 OUT IN 2 GND 1 FB 6650 SS U PACKAGE DESCRIPTIO S5 Package 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635 Rev B) 0.62 MAX 0.95 REF 2.90 BSC (NOTE 4) 1.22 REF 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 TYP 5 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) NOTE: 1.
PAGE 12
LT6650 U TYPICAL APPLICATIO Adjustable Micropower “Zener” 2-Terminal Reference CATHODE 4 CATHODE 5 IN 1nF OUT LT6650 FB RF 1 GND 10µF = 1.4V ≤ VZ ≤ 18V 30µA ≤ IZ ≤ 220µA VZ = 0.4V • (1 + RF/RG) RG 2 ANODE ANODE 6650 TA02 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1790 Micropower LDO Precision Reference 0.05% Max Sources/Sinks-Current Available in SOT-23 LT1460 Micropower Precision Reference 0.