Datasheet

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LT6654

6654fa

TYPICAL APPLICATION

DESCRIPTION

SOT-23 Precision Wide

Supply High Output Drive

Low Noise Reference

The LT

6654 is a family of small precision voltage ref-

erences that offers high accuracy, low noise, low drift,

low dropout and low power. The LT6654 operates from

voltages up to 36V and is fully speciﬁ ed from –55°C to

125°C. A buffered output ensures ±10mA of output drive

with low output impedance and precise load regulation.

These features, in combination, make the LT6654 ideal

for portable equipment, industrial sensing and control,

and automotive applications.

The LT6654 was designed with advanced manufactur-

ing techniques and curvature compensation to provide

10ppm/°C temperature drift and 0.05% initial accuracy.

Low thermal hysteresis ensures high accuracy and

1.6ppm

P-P

noise minimizes measurement uncertainty.

Since the LT6654 can also sink current, it can operate

as a low power negative voltage reference with the same

precision as a positive reference.

The LT6654 is offered in a 6-lead SOT-23 package.

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and

ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property

of their respective owners.

Basic Connection

Low Drift:

A Grade: 10ppm/°C Max

B Grade: 20ppm/°C Max

High Accuracy:

A Grade: ±0.05% Max

B Grade: ±0.10% Max

Low Noise: 1.6ppm

P-P

(0.1Hz to 10Hz)

Wide Supply Range to 36V

Low Thermal Hysteresis

Line Regulation (Up to 36V): 5ppm/V Max

Low Dropout Voltage: 100mV Max

Sinks and Sources ±10mA

Load Regulation at 10mA: 8ppm/mA Max

Easily Conﬁ gured for Negative Voltage Output

Fully Speciﬁ ed from –55°C to 125°C

Available Output Voltage Options: 1.25V, 2.048V, 2.5V,

3V, 3.3V, 4.096V, 5V

Low Proﬁ le (1mm) ThinSOT™ Package

FEATURES

APPLICATIONS

Automotive Control and Monitoring

High Temperature Industrial

High Resolution Data Acquisition Systems

Instrumentation and Process Control

Precision Regulators

Medical Equipment

Output Voltage Temperature Drift

LT6654

0.1µF

OUT

+ 0.5V) < V

< 36V

1µF

OUT

6654 TA01a

TEMPERATURE (°C)

–60

–0.10

OUT

ACCURACY (%)

–0.05

0.05

0.00

0.10

40200–40 –20

6654 TA01b

140

100

120

3 TYPICAL PARTS

LT6654-2.5

Summary of content (18 pages)

PAGE 1
LT6654 SOT-23 Precision Wide Supply High Output Drive Low Noise Reference DESCRIPTION FEATURES n n n n n n n n n n n n n Low Drift: A Grade: 10ppm/°C Max B Grade: 20ppm/°C Max High Accuracy: A Grade: ±0.05% Max B Grade: ±0.10% Max Low Noise: 1.6ppmP-P (0.
PAGE 2
LT6654 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) Input Voltage VIN to GND ........................... –0.3V to 38V Output Voltage VOUT .........................–0.3V to VIN + 0.3V Output Short-Circuit Duration ......................... Indeﬁnite Speciﬁed Temperature Range H-Grade ............................................. –40°C to 125°C MP-Grade .......................................... –55°C to 125°C Operating Temperature Range................
PAGE 3
LT6654 AVAILABLE OPTIONS OUTPUT VOLTAGE 1.25V INITIAL ACCURACY TEMPERATURE COEFFICIENT 0.05% 10ppm/°C 0.1% 20ppm/°C 0.05% 10ppm/°C 0.1% 20ppm/°C 2.048V 0.05% 10ppm/°C 0.1% 20ppm/°C 0.05% 10ppm/°C 0.1% 20ppm/°C 2.5V 0.05% 10ppm/°C 0.1% 20ppm/°C 0.05% 10ppm/°C 0.1% 20ppm/°C 3V 0.05% 10ppm/°C 0.1% 20ppm/°C 0.05% 10ppm/°C 0.1% 20ppm/°C 3.3V 0.05% 10ppm/°C 0.1% 20ppm/°C 0.05% 10ppm/°C 0.1% 20ppm/°C 4.096V 0.05% 10ppm/°C 0.1% 20ppm/°C 0.05% 10ppm/°C 0.1% 20ppm/°C 5V 0.05% 10ppm/°C 0.1% 20ppm/°C 0.05% 10ppm/°C 0.
PAGE 4
LT6654 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C, CL = 1μF and VIN = VOUT + 0.5V, unless otherwise noted. For LT6654-1.25, VIN = 2.4V, unless otherwise noted. PARAMETER CONDITIONS Load Regulation (Note 4) IOUT(SINK) = 10mA LT6654-2.048, LT6654-2.5, LT6654-3, LT6654-3.3, LT6654-4.096, LT6654-5 LT6654-1.25 Dropout Voltage (Note 5) Minimum Input Voltage MIN VIN – VOUT , ΔVOUT = 0.
PAGE 5
LT6654 TYPICAL PERFORMANCE CHARACTERISTICS The characteristic curves are similar across the LT6654 family. Curves from the LT6654-1.25, LT6654-2.5 and the LT6654-5 represent the full range of typical performance of all voltage options. Characteristic curves for other output voltages fall between these curves and can be estimated based on their output. 1.25V Output Voltage Temperature Drift 1.2520 1.25V Output Impedance vs Frequency 1.25V Turn-On Characteristics 100 THREE TYPICAL PARTS 1.
PAGE 6
LT6654 TYPICAL PERFORMANCE CHARACTERISTICS The characteristic curves are similar across the LT6654 family. Curves from the LT6654-1.25, LT6654-2.5 and the LT6654-5 represent the full range of typical performance of all voltage options. Characteristic curves for other output voltages fall between these curves and can be estimated based on their output. 2.5V Output Voltage Temperature Drift 2.5V Supply Current vs Input Voltage 2.502 2.5V Line Regulation 600 THREE TYPICAL PARTS 2.5050 2.5040 –40°C 2.
PAGE 7
LT6654 TYPICAL PERFORMANCE CHARACTERISTICS The characteristic curves are similar across the LT6654 family. Curves from the LT6654-1.25, LT6654-2.5 and the LT6654-5 represent the full range of typical performance of all voltage options. Characteristic curves for other output voltages fall between these curves and can be estimated based on their output. 2.5V Integrated Noise 10Hz to 10kHz 2.5V Power Supply Rejection Ratio vs Frequency –20 10 1 0.1 0.
PAGE 8
LT6654 TYPICAL PERFORMANCE CHARACTERISTICS The characteristic curves are similar across the LT6654 family. Curves from the LT6654-1.25, LT6654-2.5 and the LT6654-5 represent the full range of typical performance of all voltage options. Characteristic curves for other output voltages fall between these curves and can be estimated based on their output. 5V Output Voltage Temperature Drift 5.003 5V Output Impedance vs Frequency 5V Turn-On Characteristics 100 THREE TYPICAL PARTS 5.001 5.
PAGE 9
LT6654 PIN FUNCTIONS GND (Pin 1): Internal Function. This pin must be tied to ground, near Pin 2. DNC (Pin 5): Do Not Connect. Keep leakage current from this pin to VIN or GND to a minimum. GND (Pin 2): Primary Device Ground. VOUT (Pin 6): Output Voltage. An output capacitor of 1μF minimum is required for stable operation. DNC (Pin 3): Do Not Connect. Keep leakage current from this pin to VIN or GND to a minimum. VIN (Pin 4): Power Supply. Bypass VIN with a 0.1μF capacitor to ground.
PAGE 10
LT6654 APPLICATIONS INFORMATION Bypass and Load Capacitors The LT6654 voltage references should have an input bypass capacitor of 0.1μF or larger, however the bypassing on other components nearby is sufﬁcient. In high voltage applications, VIN > 30V, an output short-circuit to ground can create an input voltage transient that could exceed the maximum input voltage rating. To prevent this worst-case condition, an RC input line ﬁlter of 10μs (i.e. 10Ω and 1μF) is recommended.
PAGE 11
LT6654 APPLICATIONS INFORMATION Positive or Negative Operation IOUT –0.5mA In addition to the series connection, as shown on the front page of this data sheet, the LT6654 can be operated as a negative voltage reference. 0.5mA VOUT 20mV/DIV/AC 2.5V/DC CLOAD = 1μF 50μs/DIV 6654 F04 Figure 4. LT6654-2.5 Sourcing and Sinking 0.5mA The circuit in Figure 7 shows an LT6654 conﬁgured for negative operation.
PAGE 12
LT6654 APPLICATIONS INFORMATION Long-Term Drift Long-term drift cannot be extrapolated from accelerated high temperature testing. This erroneous technique gives drift numbers that are wildly optimistic. The only way long-term drift can be determined is to measure it over the time interval of interest. The LT6654 drift data was taken on 40 parts that were soldered into PC boards similar to a real world application.
PAGE 13
LT6654 TYPICAL APPLICATIONS Power Dissipation The LT6654 includes output current limit circuitry, as well as thermal limit circuitry, to protect the reference from damage in the event of excessive power dissipation. The LT6654 is protected from damage by a thermal shutdown circuit. However, changes in performance may occur as a result of operation at high temperature. T = 150°C eJA = 192°C/W 0.6 POWER (W) 0.5 0.4 0.3 130mW 0.2 0.1 0 0 20 40 60 80 100 TEMPERATURE (°C) 120 140 6654 F09 Figure 9.
PAGE 14
LT6654 APPLICATIONS INFORMATION PC Board Layout IR Reﬂow Shift The mechanical stress of soldering a surface mount voltage reference to a PC board can cause the output voltage to shift and temperature coefﬁcient to change. These two changes are not correlated. For example, the voltage may shift but the temperature coefﬁcient may not. The different expansion and contraction rates of the materials that make up the LT6654 package may cause the output voltage to shift after undergoing IR reﬂow.
PAGE 15
LT6654 TYPICAL APPLICATIONS Extended Supply Range Reference Boosted Output Current Reference 4.5V < VIN < 36V UP TO 160V 4.7μF 220Ω 330k MMBT5551 2N2905 IN BZX84C12 LT6654-2.5 0.1μF IOUT UP TO 300mA LT6654-2.5 OUT 1μF 1μF 6654 TA02 6654 TA03 Boosted Output Current with Current Limit Octal DAC Reference 4.5V < VIN < 36V LT6654-2.5 2.65V < VIN < 5V IN OUT VIN 1 LED1* 220Ω 4.7μF 0.1μF 10Ω 10μF 2 VREF 2N2905 VCC CS LT6654-2.5 IN IOUT UP TO 100mA OUT SCK 0.
PAGE 16
LT6654 PACKAGE DESCRIPTION S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 0.62 MAX 2.90 BSC (NOTE 4) 0.95 REF 1.22 REF 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 6 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) 1.90 BSC S6 TSOT-23 0302 REV B NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3.
PAGE 17
LT6654 REVISION HISTORY REV DATE DESCRIPTION PAGE NUMBER A 12/10 Added voltage options (1.250V, 2.048V, 3.000V, 4.096V, 5.000V) reﬂected throughout the data sheet. 1-18 6654fa 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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
PAGE 18
LT6654 TYPICAL APPLICATION 16-Bit ADC Reference 4.6V < VS < 36V LT6654-4.096 IN OUT 10μF 0.1μF + IN+ –2.048V < VDIFFERENTIAL < 2.048V – VREF VCC LTC2480 IN– GND fO SDO SDI CS TO MCU SCK 6654 TA06 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1460 Micropower Series Reference 0.075% Max, 10ppm/°C Max Drift, 2.