View LTC6655_4622147.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

LTC6655 0.25ppm Noise, Low Drift Precision Buffered Reference Family FeaTures
n n n n n n n n n n n
DescripTion
The LTC(R)6655 is a complete family of precision bandgap voltage references, offering exceptional noise and drift performance. This low noise and drift is ideally suited for the high resolution measurements required by instrumentation and test equipment. In addition, the LTC6655 is fully specified over the temperature range of -40C to 125C, ensuring its suitability for demanding automotive and industrial applications. Advanced curvature compensation allows this bandgap reference to achieve a drift of less than 2ppm/C with a predictable temperature characteristic and an output voltage accurate to 0.025%, reducing or eliminating the need for calibration. The LTC6655 can be powered from as little as 500mV above the output voltage to as much as 13.2V. Superior load regulation with source and sink capability, coupled with exceptional line rejection, ensures consistent performance over a wide range of operating conditions. A shutdown mode is provided for low power applications. Available in a small MSOP package, the LTC6655 family of references is an excellent choice for demanding precision applications.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
n
Low Noise: 0.25ppmP-P (0.1Hz to 10Hz) 625nVP-P for the LTC6655-2.5 Low Drift: 2ppm/C Max High Accuracy: 0.025% Max Fully Specified from -40C to 125C 100% Tested at -40C, 25C and 125C Load Regulation: <10ppm/mA Sinks and Sources Current: 5mA Low Dropout: 500mV Maximum Supply Voltage: 13.2V Low Power Shutdown: <20A Max Available Output Voltages: 1.25V, 2.048V, 2.5V, 3V, 3.3V, 4.096V, 5V Available in an 8-Lead MSOP Package
applicaTions
n n n n n n n
n
Instrumentation and Test Equipment High Resolution Data Acquisition Systems Weigh Scales Precision Battery Monitors High Temperature Applications Precision Regulators Medical Equipment High Output Current Precision Reference
Typical applicaTion
Low Frequency 0.1Hz to 10Hz Noise (LTC6655-2.5) Basic Connection
LTC6655-2.5 3V < VIN 13.2V CIN 0.1F VIN SHDN GND VOUT_F VOUT_S VOUT COUT 10F
6655 TA01a
500nV/DIV
1s/DIV
6655 TA01b
6655fa
LTC6655 absoluTe MaxiMuM raTings
(Note 1)
pin conFiguraTion
TOP VIEW SHDN VIN GND* GND 1 2 3 4 8 7 6 5 GND* VOUT_F VOUT_S GND*
Input Voltage VIN to GND .......................................... -0.3V to 13.2V SHDN to GND ........................... -0.3V to (VIN + 0.3V) Output Voltage: VOUT_F ...................................... -0.3V to (VIN + 0.3V) VOUT_S ..................................................... -0.3V to 6V Output Short-Circuit Duration ...................... Indefinite Operating Temperature Range (Note 2) . -40C to 125C Storage Temperature Range (Note 2)..... -65C to 150C Lead Temperature Range (Soldering, 10 sec) (Note 3)................................................................. 300C
MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 150C, JA = 300C/W *CONNECT PINS TO DEVICE GND (PIN 4)
orDer inForMaTion
LEAD FREE FINISH LTC6655BHMS8-1.25#PBF LTC6655CHMS8-1.25#PBF LTC6655BHMS8-2.048#PBF LTC6655CHMS8-2.048#PBF LTC6655BHMS8-2.5#PBF LTC6655CHMS8-2.5#PBF LTC6655BHMS8-3#PBF LTC6655CHMS8-3#PBF LTC6655BHMS8-3.3#PBF LTC6655CHMS8-3.3#PBF LTC6655BHMS8-4.096#PBF LTC6655CHMS8-4.096#PBF LTC6655BHMS8-5#PBF LTC6655CHMS8-5#PBF TAPE AND REEL LTC6655BHMS8-1.25#TRPBF LTC6655CHMS8-1.25#TRPBF LTC6655BHMS8-2.048#TRPBF LTC6655CHMS8-2.048#TRPBF LTC6655BHMS8-2.5#TRPBF LTC6655CHMS8-2.5#TRPBF LTC6655BHMS8-3#TRPBF LTC6655CHMS8-3#TRPBF LTC6655BHMS8-3.3#TRPBF LTC6655CHMS8-3.3#TRPBF LTC6655BHMS8-4.096#TRPBF LTC6655CHMS8-4.096#TRPBF LTC6655BHMS8-5#TRPBF LTC6655CHMS8-5#TRPBF PART MARKING LTFDG LTFDG LTFDH LTFDH LTFCY LTFCY LTFDJ LTFDJ LTFDK LTFDK LTFDM LTFDM LTFDN LTFDN PACKAGE DESCRIPTION 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic MSOP SPECIFIED TEMPERATURE RANGE -40C to 125C -40C to 125C -40C to 125C -40C to 125C -40C to 125C -40C to 125C -40C to 125C -40C to 125C -40C to 125C -40C to 125C -40C to 125C -40C to 125C -40C to 125C -40C to 125C
Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
6655fa
LTC6655 aVailable opTions
OUTPUT VOLTAGE 1.250 2.048 2.500 3.000 3.300 4.096 5.000 INITIAL ACCURACY 0.025% 0.05% 0.025% 0.05% 0.025% 0.05% 0.025% 0.05% 0.025% 0.05% 0.025% 0.05% 0.025% 0.05% TEMPERATURE COEFFICIENT 2ppm/C 5ppm/C 2ppm/C 5ppm/C 2ppm/C 5ppm/C 2ppm/C 5ppm/C 2ppm/C 5ppm/C 2ppm/C 5ppm/C 2ppm/C 5ppm/C PART NUMBER LTC6655BHMS8-1.25 LTC6655CHMS8-1.25 LTC6655BHMS8-2.048 LTC6655CHMS8-2.048 LTC6655BHMS8-2.5 LTC6655CHMS8-2.5 LTC6655BHMS8-3.0 LTC6655CHMS8-3.0 LTC6655BHMS8-3.3 LTC6655CHMS8-3.3 LTC6655BHMS8-4.096 LTC6655CHMS8-4.096 LTC6655BHMS8-5 LTC6655CHMS8-5
See Order Information section for complete part number listing.
The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VIN = VOUT + 0.5V, VOUT_S connected to VOUT_F, unless otherwise noted.
PARAMETER Output Voltage Output Voltage Temperature Coefficient (Note 4) Line Regulation Load Regulation (Note 5) CONDITIONS LTC6655B LTC6655C LTC6655B LTC6655C VOUT + 0.5V VIN 13.2V, SHDN = VIN
l l l
elecTrical characTerisTics
MIN -0.025 -0.05
TYP
MAX 0.025 0.05
UNITS % % ppm/C ppm/C ppm/V ppm/V ppm/mA ppm/mA ppm/mA ppm/mA V V V mA mA
1 2.5 5 3
2 5 25 40 15 30 13.2 13.2 13.2
ISOURCE = 5mA
l
ISINK = 5mA
l
10
Operating Voltage (Note 6)
LTC6655-1.25, LTC6655-2.048, LTC6655-2.5 ISOURCE = 5mA, VOUT Error 0.1% LTC6655-3, LTC6655-3.3, LTC6655-4.096, LTC6655-5 ISOURCE = 5mA, VOUT Error 0.1% IOUT = 0mA, VOUT Error 0.1%
l
3
l VOUT + 0.5 l VOUT + 0.2
Output Short-Circuit Current Shutdown Pin (SHDN)
Short VOUT to GND Short VOUT to VIN Logic High Input Voltage Logic High Input Current, SHDN = 2V Logic Low Input Voltage Logic Low Input Current, SHDN = 0.8V
l l l l
20 20 2.0 12 0.8 15 5
l l
V A V A mA mA A
Supply Current Shutdown Current
No Load SHDN Tied to GND
7 7.5 20
6655fa
LTC6655
The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VIN = VOUT + 0.5V, VOUT_S connected to VOUT_F, unless otherwise noted.
PARAMETER Output Voltage Noise (Note 7) Turn-On Time Long-Term Drift of Output Voltage (Note 8) Hysteresis (Note 9) T = -0C to 70C T = -40C to 85C T = -40C to 125C CONDITIONS 0.1Hz f 10Hz 10Hz f 1kHz 0.1% Settling, COUT = 2.7F MIN TYP 0.25 0.67 400 60 30 35 60 MAX UNITS ppmP-P ppmRMS s ppm/kHr ppm ppm ppm
elecTrical characTerisTics
Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: Precision may be affected if the parts are stored outside of the specified temperature range. Large temperature changes may cause changes in device performance due to thermal hysteresis. For best performance, extreme temperatures should be avoided whenever possible. Note 3: The stated temperature is typical for soldering of the leads during manual rework. For detailed IR reflow recommendations, refer to the Applications Information section. Note 4: Temperature coefficient is measured by dividing the maximum change in output voltage by the specified temperature range. Note 5: Load regulation is measured on a pulse basis from no load to the specified load current. Load current does not include the 2mA sense current. Output changes due to die temperature change must be taken into account separately. Note 6: Excludes load regulation errors. Minimum supply for the LTC6655-1.25, LTC6655-2.048 and LTC6655-2.5 is set by internal circuitry supply requirements, regardless of load condition. Minimum supply for the LTC6655-3, LTC6655-3.3, LTC6655-4.096 and LTC6655-5 is specified by load current. Note 7: Peak-to-peak noise is measured with a 2-pole highpass filter at 0.1Hz and 3-pole lowpass filter at 10Hz. The unit is enclosed in a still-air environment to eliminate thermocouple effects on the leads, and the test time is 10 seconds. Due to the statistical nature of noise, repeating
noise measurements will yield larger and smaller peak values in a given measurement interval. By repeating the measurement for 1000 intervals, each 10 seconds long, it is shown that there are time intervals during which the noise is higher than in a typical single interval, as predicted by statistical theory. In general, typical values are considered to be those for which at least 50% of the units may be expected to perform similarly or better. For the 1000 interval test, a typical unit will exhibit noise that is less than the typical value listed in the Electrical Characteristics table in more than 50% of its measurement intervals. See Application Note 124 for noise testing details. RMS noise is measured with a spectrum analyzer in a shielded environment. Note 8: Long-term stability typically has a logarithmic characteristic and therefore, changes after 1000 hours tend to be much smaller than before that time. Total drift in the second thousand hours is normally less than one-third that of the first thousand hours with a continuing trend toward reduced drift with time. Long-term stability is also affected by differential stresses between the IC and the board material created during board assembly. Note 9: Hysteresis in output voltage is created by mechanical stress that differs depending on whether the IC was previously at a higher or lower temperature. Output voltage is always measured at 25C, but the IC is cycled to the hot or cold temperature limit before successive measurements. Hysteresis is roughly proportional to the square of the temperature change. For instruments that are stored at well controlled temperatures (within 20 or 30 degrees of operational temperature), hysteresis is usually not a significant error source.
6655fa
LTC6655 Typical perForMance characTerisTics
1.25V Low Frequency 0.1Hz to 10Hz Noise
1.2504
Characteristic curves are similar for most voltage options of the LTC6655. Curves from the LTC6655-1.25, LTC6655-2.5 and the LTC6655-5 represent the range of performance across the entire family of references. Characteristic curves for other output voltages fall between these curves and can be estimated based on their voltage output. 1.25V Output Voltage Temperature Drift
3 TYPICAL UNITS OUTPUT VOLTAGE CHANGE (ppm) 20 10 0 -10 -20 -30 -40 0.001
1.25V Load Regulation (Sourcing)
125C 25C -40C
200nV/ DIV
OUTPUT VOLTAGE (V)
6655 G01
1.2502
1.2500
1.2498
1s/DIV
1.2496 -50
-25
50 25 0 75 TEMPERATURE (C)
100
125
0.01 0.1 1 OUTPUT CURRENT (mA)
10
6655 G03
6655 G02
1.25V Load Regulation (Sinking)
200 OUTPUT VOLTAGE CHANGE (ppm) 160 125C 25C -40C NOISE VOLTAGE (nV/Hz) 40 35 30 25 20 15 10 5 0 0.001 0.01 0.1 1 OUTPUT CURRENT (mA) 10
6655 G04
1.25V Output Voltage Noise Spectrum
1.25V Sinking Current with a 3.3F Output Capacitor
IOUT
5mA 0mA
120
80 40
VOUT 10mV/DIV
0 0.01
2.7F 10F 100F 0.1 1 10 FREQUENCY (kHz) 100 1000
6655 G05
COUT = 3.3F
200s/DIV
6655 G06
1.25V Sourcing Current with a 3.3F Output Capacitor
14 12 SUPPLY CURRENT (A) 10 8 6 4 2 0
1.25V Shutdown Supply Current vs Input Voltage
125C 25C -40C NUMBER OF PARTS 60 50 40 30 20 10
1.25V VOUT Distribution
TA = 25C
0mA IOUT -5mA
VOUT 10mV/DIV
COUT = 3.3F
200s/DIV
6655 G07
0
2
8 6 10 4 INPUT VOLTAGE (V)
12
14
6655 G08
0 1.2495
1.2498
1.2500 VOUT (V)
1.2503
1.2505
6655 G09
6655fa
LTC6655 Typical perForMance characTerisTics
2.5V Low Frequency 0.1Hz to 10Hz Noise
2.5010
Characteristic curves are similar for most voltage options of the LTC6655. Curves from the LTC6655-1.25, LTC6655-2.5 and the LTC6655-5 represent the range of performance across the entire family of references. Characteristic curves for other output voltages fall between these curves and can be estimated based on their voltage output. 2.5V Output Voltage Temperature Drift
3 TYPICAL UNITS OUTPUT VOLTAGE CHANGE (ppm) 10 0 -10 -20 -30 -40 -50 0.001 125C 25C -40C 0.01 0.1 1 OUTPUT CURRENT (mA) 10
6655 G12
2.5V Load Regulation (Sourcing)
500nV/ DIV
OUTPUT VOLTAGE (V)
6655 G10
2.5005
2.5000
2.4995
1s/DIV
2.4990 -50
0
50 100 TEMPERATURE (C)
150
6655 G11
2.5V Load Regulation (Sinking)
160 OUTPUT VOLTAGE CHANGE (ppm) 140 120 100 80 60 40 20 0 -20 0.001 0.01 0.1 1 OUTPUT CURRENT (mA) 10
6655 G13
2.5V Supply Current vs Input Voltage
8 7 SUPPLY CURRENT (mA) SUPPLY CURRENT (A) 125C 25C -40C 0 2 4 6 8 10 INPUT VOLTAGE (V) 12 14
6655 G14
2.5V Shutdown Supply Current vs Input Voltage
14 12 10 8 6 4 2 0 0 2 4 6 8 10 INPUT VOLTAGE (V) 125C 25C -40C 12 14
6655 G15
125C 25C -40C
6 5 4 3 2 1 0
2.5V Minimum VIN - VOUT Differential (Sourcing)
10 10
2.5V Minimum VIN - VOUT Differential (Sinking)
120 100
2.5V Output Voltage Noise Spectrum
COUT = 2.7F
OUTPUT CURRENT (mA)
1
OUTPUT CURRENT (mA)
NOISE VOLTAGE (nVHz)
1
80 60 40 20 0 0.01
COUT = 10F COUT = 100F
0.1 125C 25C -40C 0.1 INPUT - OUTPUT VOLTAGE (V) 1
6655 G16
0.1 125C 25C -40C -0.05 0.05 INPUT - OUTPUT VOLTAGE (V) 0.15
6655 G17
0.01 0.01
0.01 -0.15
0.1
1 10 FREQUENCY (kHz)
100
1000
6655 F01
6655fa
LTC6655 Typical perForMance characTerisTics
2.5V Temperature Drift Distribution
14 12 NUMBER OF PARTS 10 8 6 4 2 2.4996 2.5000 VOUT (V) 2.5004 2.5008
6655 G19
Characteristic curves are similar for most voltage options of the LTC6655. Curves from the LTC6655-1.25, LTC6655-2.5 and the LTC6655-5 represent the range of performance across the entire family of references. Characteristic curves for other output voltages fall between these curves and can be estimated based on their voltage output. 2.5V VOUT Distribution
100 90 80 NUMBER OF PARTS 70 60 50 40 30 20 10 0 2.4992 TA = 25C
-40C TO 125C
2.5
2.5V SHDN Input Voltage Thresholds vs VIN
2.0 VTH_UP VTRIP (V) 1.5 VTH_DN
1.0
0.5
0
0
0.4
0.8
1.2
1.6
2
2.4
2.8
6655 G20
0.0
2
4
6
DRIFT (ppm/C)
8 VIN (V)
10
12
14
6655 G21
2.5V Power Supply Rejection Ratio vs Frequency
120 POWER SUPPLY REJECTION RATIO (dB) 100 OUTPUT IMPEDENCE ( ) 80 60 40 20 0 0.001 COUT = 2.7F COUT = 10F COUT = 100F 0.01 0.1 1 FREQUENCY (kHz) 10 100
6655 G22
2.5V Output Impedance vs Frequency
10 COUT = 2.7F COUT = 10F COUT = 100F OUTPUT VOLTAGE (V) 2.502
2.5V Line Regulation
2.501
1
2.500
0.1
2.499 125C 25C -40C 0 2 10 4 6 8 INPUT VOLTAGE (V) 12 14
0.01 0.001
0.01
0.1 1 10 FREQUENCY (kHz)
100
1000
6655 G23
2.498
6655 G24
6655fa
LTC6655 Typical perForMance characTerisTics
5V Low Frequency 0.1Hz to 10Hz Noise
5.0010
Characteristic curves are similar for most voltage options of the LTC6655. Curves from the LTC6655-1.25, LTC6655-2.5 and the LTC6655-5 represent the range of performance across the entire family of references. Characteristic curves for other output voltages fall between these curves and can be estimated based on their voltage output. 5V Output Voltage Temperature Drift
3 TYPICAL UNITS OUTPUT VOLTAGE CHANGE (ppm) 10 0 -10 -20 -30 -40 -50 0.01 125C 25C -40C 0.1 1 OUTPUT CURRENT (mA) 10
6655 G27
5V Load Regulation (Sourcing)
5.0005 OUTPUT VOLTAGE (V)
6655 G25
5.0000
500nV/ DIV
4.9995
4.9990
1s/DIV
4.9985 -50
-25
0 25 50 75 TEMPERATURE (C)
100
125
6655 G26
5V Load Regulation (Sinking)
100 OUTPUT VOLTAGE CHANGE (ppm) 80 60 40 20 0 -20 0.01 125C 25C -40C SUPPLY CURRENT (mA) 6 5
5V Supply Current vs Input Voltage
200 180 NOISE VOLTAGE (nV/Hz) 160 140 120 100 80 60 40 20
5V Output Voltage Noise Spectrum
4 3 2 1 0 125C 25C -40C 0 2 8 6 10 4 INPUT VOLTAGE (V) 12 14
6655 G29
0.1 1 OUTPUT CURRENT (mA)
10
6655 G28
0 0.01
2.7F 10F 100F 0.1 1 10 FREQUENCY (kHz) 100 1000
6655 G30
5V Minimum VIN-VOUT Differential (Sourcing)
10 10
5V Minimum VIN-VOUT Differential (Sinking)
5V Start-Up Response with a 3.3F Output Capacitor
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
VIN 2V/DIV 1
1
VOUT 2V/DIV 0.1 125C 25C -40C -0.2 -0.1 0 INPUT-OUTPUT VOLTAGE (V) 0.1
6655 G32
0.1 125C 25C -40C 0.1 INPUT-OUTPUT VOLTAGE (V) 1
6655 G31
COUT = 3.3F
400s/DIV
6655 G33
0.01 0.01
0.01 -0.3
6655fa
LTC6655 pin FuncTions
SHDN (Pin 1): Shutdown Input. This active low input powers down the device to <20A. If left open, an internal pull-up resistor puts the part in normal operation. It is recommended to tie this pin high externally for best performance during normal operation. , VIN (Pin 2): Power Supply. Bypass VIN with a 0.1F or larger, capacitor to GND. GND (Pin 4): Device Ground. This pin is the main ground and must be connected to a noise-free ground plane. VOUT_S (Pin 6): VOUT Sense Pin. Connect this pin at the load and route with a wide metal trace to minimize load regulation errors. This pin sinks 2mA. Output error is RTRACE * 2mA, regardless of load current. For load currents <100A, tie directly to VOUT_F pin. VOUT_F (Pin 7): VOUT Force Pin. This pin sources and sinks current to the load. An output capacitor of 2.7F to 100F is required. GND (Pins 3, 5, 8): Internal Function. Ground these pins.
blocK DiagraM
2 VIN
1
SHDN
+
BANDGAP
VOUT_F
7
-
VOUT_S 6
4
GND GND 3,5,8
6655 BD
6655fa
LTC6655 applicaTions inForMaTion
Bypass and Load Capacitors The LTC6655 voltage references require a 0.1F or larger input capacitor located close to the part to improve power supply rejection. An output capacitor with a value between 2.7F and 100F is also required. The output capacitor has a direct effect on the stability, turn-on time and settling behavior. Choose a capacitor with low ESR to insure stability. Resistance in series with the output capacitor (ESR) introduces a zero in the output buffer transfer function and could cause instability. The 2.7F to 100F range includes several types of capacitors that are readily available as through-hole and surface mount components. It is recommended to keep ESR less than or equal to 0.1. Capacitance and ESR are both frequency dependent. At higher frequencies capacitance drops and ESR increases. To insure stable operation the output capacitor should have the required values at 100kHz. In order to achieve the best performance, caution should be used when choosing a capacitor. X7R ceramic capacitors are small, come in appropriate values and are relatively stable over a wide temperature range. However, for a low noise application X7R capacitors may not be suitable since they may exhibit a piezoelectric effect. The mechanical vibrations cause a charge displacement in the ceramic dielectric and the resulting perturbation can look like noise. If X7R capacitors are necessary, a thorough bench evaluation should be completed to verify proper performance.
Table 1. Film Capacitor Companies
COMPANY Cornell Dublier Dearborn Electronics Tecate Wima Vishay Vishay Dearborn Electronics Wima DIELECTRIC Polyester Polyester Polyester Polyester Polyester Polycarbonate Polyphenylene Sulfide (PPS) Polyphenylene Sulfide (PPS) AVAILABLE CAPACITANCE 0.5F to 10F 0.1F to 12F 0.01F to 18F 10F to 22F 1000pF to 15F 0.01F to 10F 0.01F to 15F 0.01F to 6.8F TEMPERATURE RANGE -55C to 125C -55C to 125C -40C to 105C -55C to 100C -55C to 125C -55C to 100C -55C to 125C -55C to 140C TYPE DME 218P 430P 431P 442P and 410P , , , , 901, 914, and 914D MKS 4, MKS 2-XL MKT1820 MKC1862, 632P 820P 832P 842P 860P and 880P , , , , SMD-PPS
For very low noise applications where every nanovolt counts, film capacitors should be considered for their low noise and lack of piezoelectric effects. Film capacitors such as polyester, polystyrene, polycarbonate, and polypropylene have good temperature stability. Additional care must be taken as polystyrene and polypropylene have an upper temperature limit of 85C to 105C. Above these temperatures, the working voltages need to be derated according to manufacturer's specifications. Another type of film capacitor is polyphenylene sulfide (PPS). These devices work over a wide temperature range, are stable, and have large capacitance values beyond 1F In general, . film capacitors are found in surface mount and leaded packages. Table 1 is a partial list of capacitor companies and some of their available products. In voltage reference applications, film capacitor lifetime is affected by temperature and applied voltage. When polyester capacitors are operated beyond their rated temperatures (some capacitors are not rated for operation above 85C) they need to be derated. Voltage derating is usually accomplished as a ratio of applied voltage to rated voltage limit. Contact specific film capacitor manufacturers to determine exact lifetime and derating information. The lifetime of X7R capacitors is long, especially for reference applications. Capacitor lifetime is degraded by operating near or exceeding the rated voltage, at high temperature, with AC ripple or some combination of these. Most reference applications have AC ripple only during transient events.
6655fa
0
LTC6655 applicaTions inForMaTion
NOISE VOLTAGE (nVHz)
The choice of output capacitor also affects the bandwidth of the reference circuitry and resultant noise peaking. As shown in Figure 1, the bandwidth is inversely proportional to the value of the output capacitor. Noise peaking is related to the phase margin of the output buffer. Higher peaking generally indicates lower phase margin. Other factors affecting noise peaking are temperature, input voltage, and output load current. Start-Up and Load Transient Response Results for the transient response plots (Figures 3 to 8) were produced with the test circuit shown in Figure 2 unless otherwise indicated. The turn-on time is slew limited and determined by the short-circuit current, the output capacitor, and output voltage as shown in the equation: tON = VOUT * COUT ISC
VIN 3V
120 100 80 60 40 20 0 0.01 COUT = 2.7F
COUT = 10F COUT = 100F
0.1
1 10 FREQUENCY (kHz)
100
1000
6655 F01
Figure 1. Output Voltage Noise Spectrum
VOUT 100 COUT 3.3F VGEN
6655 F02
1,2 CIN 0.1F
7 LTC6655-2.5 3,4,5,8 6
0.5V
Figure 2. Transient Load Test Circuit
For example, the LTC6655-2.5V, with a 3.3F output capacitor and a typical short-circuit current of 20mA, the start-up time would be approximately: 2.5V * 3.3 * 10 F = 412s 0.02A
-6
VIN 2V/DIV
The resulting turn-on time is shown in Figure 3. Here the output capacitor is 3.3F and the input capacitor is 0.1F . Figure 4 shows the output response to a 500mV step on VIN. The output response to a current step sourcing and sinking is shown in Figures 5 and 6, respectively. Figure 7 shows the output response as the current goes from sourcing to sinking. Shutdown Mode The LTC6655 family of references can be shut down by tying the SHDN pin to ground. There is an internal pull-up resistor tied to this pin. If left unconnected this pin rises to VIN and the part is enabled. Due to the low internal pull-up current, it is recommended that the SHDN pin be pulled high externally for normal operation to prevent accidental
VOUT 1V/DIV
COUT = 3.3F
200s/DIV
6655 F03
Figure 3. Start-Up Response
VIN
3.5V 3V
VOUT 50mV/DIV
COUT = 3.3F
400s/DIV
6655 F04
Figure 4. Output Response with a 500mV Step On VIN
6655fa
LTC6655 applicaTions inForMaTion
0mA IOUT -5mA
shutdown due to system noise or leakage currents. The turn-on/turn-off response due to shutdown is shown in Figure 8. To control shutdown from a low voltage source, a MOSFET can be used as a pull-down device as shown in Figure 9. Note that an external resistor is unnecessary. A MOSFET with a low drain-to-source leakage over the operating temperature range should be chosen to avoid inadvertently pulling down the SHDN pin. A resistor may be added from SHDN to VIN to overcome excessive MOSFET leakage. The SHDN thresholds have some dependency on VIN and temperature as shown in the Typical Performance Characteristics section. Avoid leaving SHDN at a voltage between the thresholds as this will cause an increase in supply current due to shoot-through current.
3V VIN 13.2V COUT = 3.3F 200s/DIV
6655 F06
VOUT 10mV/DIV
COUT = 3.3F
200s/DIV
6655 F05
Figure 5. Output Response with a 5mA Load Step Sourcing
5mA
IOUT 0mA
VOUT 10mV/DIV C1 1F VIN
VOUT_F
VOUT C2 10F
LTC6655-2.5 SHDN TO C 2N7002 GND VOUT_S
Figure 6. Output Response with 5mA Load Step Sinking
6655 F09
IOUT -2mA
2mA
Figure 9. Open-Drain Shutdown Circuit
Long-Term Drift
VOUT 10mV/DIV
COUT = 3.3F
200s/DIV
6655 F07
Figure 7. Output Response Showing a Sinking to Sourcing Transition
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 LTC6655 long-term drift data was collected on 80 parts that were soldered into printed circuit boards similar to a real world application. The boards were then placed into a constant temperature oven with a TA = 35C, their outputs were scanned regularly and measured with an 8.5 digit DVM. Typical long-term drift is illustrated in Figure 10.
SHDN 2V/DIV
VOUT 1V/DIV
COUT = 3.3F
1ms/DIV
6655 F08
Figure 8. Shutdown Response with 5mA Source Load
6655fa
LTC6655 applicaTions inForMaTion
120 4 TYPICAL UNITS LTC6655-2.5 30 25 NUMBER OF UNITS 0 500 1500 1000 HOURS 2000 2500
6655 F10
LONG-TERM DRIFT (ppm)
80
40
20 15 10 5 0 -90 -70 -50 -30 -10 10 30 50 70 90 110 DISTRIBUTION (ppm)
6655 F11
0 -40
-80
Figure 10. Long-Term Drift
Figure 11. Hysteresis Plot -40C to 125C
0.14 0.12 0.10 POWER (W) 0.08 0.06 0.04 0.02 0 0 5 VIN (V) 10 15
6655 F12
Hysteresis Thermal hysteresis is a measure of change of output voltage as a result of temperature cycling. Figure 11 illustrates the typical hysteresis based on data taken from the LTC6655-2.5. A proprietary design technique minimizes thermal hysteresis. Power Dissipation Power dissipation for the LTC6655 depends on VIN and load current. Figure 12 illustrates the power consumption versus VIN under a no-load and 5mA load condition at room temperature for the LTC6655-2.5. Other voltage options display similar behavior. The MSOP8 package has a thermal resistance (JA) equal to 300C/W. Under the maximum loaded condition, the increase in die temperature is over 35C. If operated at these conditions with an ambient temperature of 125C, the absolute maximum junction temperature rating of the device would be exceeded. Although the maximum junction temperature is 150C, for best performance it is recommended to not exceed a junction temperature of 125C. The plot in Figure 13 shows the recommended maximum ambient temperature limits for differing VIN and load conditions using a maximum junction temperature of 125C.
5mA LOAD
NO LOAD
Figure 12. LTC6655-2.5 Power Consumption
125 MAXIMUM AMBIENT OPERATING TEMPERATURE (C) 115 105 5mA LOAD 95 85 75 65 55 0 3 6 VIN (V) 9 12 15
6655 F13
NO LOAD
Figure 13. LTC6655-2.5 Maximum Ambient Operating Temperature
6655fa
LTC6655 applicaTions inForMaTion
PC Board Layout The LTC6655 reference is a precision device that is factory trimmed to an initial accuracy of 0.025%, as shown in the Typical Performance Characteristic section. The mechanical stress caused by soldering parts to a printed circuit board may cause the output voltage to shift and the temperature coefficient to change. To reduce the effects of stress-related shifts, mount the reference near the short edge of a printed circuit board or in a corner. In addition, slots can be cut into the board on two sides of the device to reduce mechanical stress. A thicker and smaller board is stiffer and less prone to bend. Finally, use stress relief, such as flexible standoffs, when mounting the board. Additional precautions include making sure the solder joints are clean and the board is flux free to avoid leakage paths. A sample PCB layout is shown in Figure 14.
VIN 7
+
2
LTC6655-2.5
6 4
2mA
LOAD STAR
6655 F15
MINIMIZE RESISTANCE OF METAL
Figure 15. Kelvin Connection for Good Load Regulation
output current <100A), VOUT_S should be tied to VOUT_F by the shortest possible path to reduce errors caused by resistance in the sense trace. Careful attention to grounding is also important, especially when sourcing current. The return load current can produce an I * R drop causing poor load regulation. Use a "star" ground connection and minimize the ground to load metal resistance. Although there are several pins that are required to be connected to ground, Pin 4 is the actual ground for return current. Optimal Noise Performance The LTC6655 offers extraordinarily low noise for a bandgap reference--only 0.25ppm in 0.1Hz to 10Hz. As a result, system noise performance may be dominated by system design and physical layout.
GND
VOUT
6655 F14
Figure 14. Sample PCB Layout
Load Regulation To take advantage of the VOUT Kelvin force/sense pins, the VOUT_S pin should be connected separately from the VOUT_F pin as shown in Figure 15. The VOUT_S pin sinks 2mA, which is unusual for a Kelvin connection. However, this is required to achieve the exceptional low noise performance. The I * R drop on the VOUT_S line directly affects load regulation. The VOUT_S trace should be as short and wide as practical to minimize series resistance The VOUT_S trace adds error as RTRACE * 2mA, so a 0.1 trace adds 200V error. The VOUT_F pin is not as important as the VOUT_S pin in this regard. An I * R drop on the VOUT_F pin increases the minimum supply voltage when sourcing current, but does not directly affect load regulation. For light loading of the output (maximum
Some care is required to achieve the best possible noise performance. The use of dissimilar metals in component leads and PC board traces creates thermocouples. Variations in thermal resistance, caused by uneven air flow, create differential lead temperatures, thereby causing thermoelectric voltage noise at the output of the reference. Minimizing the number of thermocouples, as well as limiting airflow, can substantially reduce these errors. Additional information can be found in Linear Technology Application Note 82. Position the input and load capacitors close to the part. Although the LTC6655 has a DC PSRR of over 100dB, the power supply should be as stable as possible to guarantee optimal performance. A plot of the 0.1Hz to 10Hz low frequency noise is shown in the Typical Performance Characteristic section. Noise performance can be further improved by wiring several LTC6655s in parallel as shown in the Typical Applications section. With this technique the noise is reduced by N, where N is the number of LTC6655s in parallel.
6655fa
LTC6655 applicaTions inForMaTion
Noise Specification Noise in any frequency band is a random function based on physical properties such as thermal noise, shot noise, and flicker noise. The most precise way to specify a random error such as noise is in terms of its statistics, for example as an RMS value. This allows for relatively simple maximum error estimation, generally involving assumptions about noise bandwidth and crest factor. Unlike wideband noise, low frequency noise, typically specified in a 0.1Hz to 10Hz band, has traditionally been specified in terms of expected error, illustrated as peak-to-peak error. Low frequency noise is generally measured with an oscilloscope over a 10 second time frame. This is a pragmatic approach, given that it can be difficult to measure noise accurately at low frequencies, and that it can also be difficult to agree on the statistical characteristics of the noise, since flicker noise dominates the spectral density. While practical, a random sampling of 10 second intervals is an inadequate method for representation of low frequency noise, especially for systems where this noise is a dominant limit of system performance. Given the random nature of noise, the output voltage may be observed over many time intervals, each giving different results. Noise specifications that were determined using this method are prone to subjectivity, and will tend toward a mean statistical value, rather than the maximum noise that is likely to be produced by the device in question. Because the majority of voltage reference data sheets express low frequency noise as a typical number, and as it tends to be illustrated with a repeatable plot near the mean of a distribution of peak-to-peak values, the LTC6655 data sheet provides a similarly defined typical specification in order to allow a reasonable direct comparison against similar products. Data produced with this method generally suggests that in a series of 10 second output voltage measurements, at least half the observations should have a peak-to-peak value that is below this number. For example, the LTC6655-2.5 measures less than 0.25ppmP-P in at least 50% of the 10 second observations. As mentioned above, the statistical distribution of noise is such that if observed for long periods of time, the peak error in output voltage due to noise may be much larger than that observed in a smaller interval. The likely maximum error due to noise is often estimated using the RMS value, multiplied by an estimated crest factor, assumed to be in the range of 6 to 8.4. This maximum possible value will only be observed if the output voltage is measured for very long periods of time. Therefore, in addition to the common method, a more thorough approach to measuring noise has been used for the LTC6655 (described in detail in Linear Technology's AN124) that allows more information to be obtained from the result. In particular, this method characterizes the noise over a significantly greater length of time, resulting in a more complete description of low frequency noise. The peak-to-peak voltage is measured for 10 second intervals over hundreds of intervals. In addition, an electronic peak-detect circuit stores an objective value for each interval. The results are then summarized in terms of the fraction of measurement intervals for which observed noise is below a specified level. For example, the LTC6655-2.5 measures less than 0.27ppmP-P in 80% of the measurement intervals, and less than 0.295ppmP-P in 95% of observation intervals. This statistical variation in noise is illustrated in Table 2 and Figure 17. The test circuit is shown in Figure 16.
Table 2
50% 60% 70% 80% 90% Low Frequency Noise (ppmP-P) 0.246 0.252 0.260 0.268 0.292
This method of testing low frequency noise is superior to more common methods. The results yield a comprehensive statistical description, rather than a single observation. In addition, the direct measurement of output voltage over time gives an actual representation of peak noise, rather than an estimate based on statistical assumptions such as crest factor. Additional information can be derived from a measurement of low frequency noise spectral density, as shown in Figure 18. It should be noted from Figure 18 that the LTC6655 has not only a low wideband noise, but an exceptionally low flicker noise corner of 1Hz! This substantially reduces low frequency noise, as well as long-term variation in peak noise.
6655fa
LTC6655
+
IN - INPUT 10 * 330F 16V 330F 16V IN OUT
SD 750 * -15V AC LINE GROUND SHIELDED CAN
LTC6655 2.5V 100k* 330 * 100 *
F
**1.2k
10k ROOT-SUM-SQUARE CORRECTION SEE TEXT
1F
+
REFERENCE UNDER TEST
applicaTions inForMaTion
0.22F +15 RST = Q2 C2 RC2
10k
RESET PULSE GENERATOR +15 +V 74C221 BAT-85 B2 BAT-85
4.7k
PEAK TO PEAK NOISE DETECTOR
RST A7 1/4 LT1058
-
+ PEAK
+
1F
P
A5 1/4 LT1058
+
1k
- +
-15 0.005F 0.1F DVM
10k
O TO 1V = O TO 1V
CLR2 +15
A2
10k
+15
100k
-
4.7k
- PEAK
TO OSCILLOSCOPE INPUT VIA ISOLATED PROBE, 1V/DIV = 1V/DIV, REFERRED TO INPUT, SWEEP = 1s/DIV
FROM OSCILLOSCOPE SWEEP GATE OUTPUT VIA ISOLATION PULSE TRANSFORMER
A8 1/4 LT1058
+
1k
* = 1% METAL FILM ** = 1% WIREWOUND, ULTRONIX105A = 1N4148 = 2N4393 = 1/4 LTC202 SEE APPENDIX C FOR POWER, SHIELDING AND GROUNDING SCHEME
RST
-
-
1F
P
100k
A6 1/4 LT1058
Q1, Q2 = THERMALLY MATED 2SK369 (MATCH VGS 10%) OR LSK389 DUAL THERMALLY LAG SEE TEXT
T P
= TANTALUM,WET SLUG ILEAK < 5nA SEE TEXT/APPENDIX B = POLYPROPELENE A4 330F OUTPUT CAPACITORS = <200nA LEAKAGE AT 1VDC AT 25C
6655 F16
+
15
10k
0.005F
Figure 16. Detailed Noise Test Circuitry. See Application Note 124.
+
+
15V 0.15F 10k 0.1F 15V 2k 1k* 1F A3 LT1012 200 * 124k* 124k* Q3 2N2907 -15V -15V
A = 100 AND 0.1Hz TO 10Hz FILTER
1N4697 10V
0.1F
1F A1 LT1012 -
4
+
- +
330F 16V A4 LT1012
A = 10 LOW NOISE PRE-AMP 1F 450 * 900 * - 100k + 5 0.022F Q1 Q2 A2 LT1097 10k* 100k 1M*
+ -
0.1F
9V
+
330F 16V
1300F
T
SHIELD
S
6655fa
LTC6655 applicaTions inForMaTion
35 30 NUMBER OF OBSERVATIONS 25 20 15 10 5 0 450 950 225 TEMPERATURE (C)
6655 F17
shown in Figure 19, the output voltage shifts. After the device expands, due to the heat, and then contracts, the stresses on the die have changed position. This shift is similar, but more extreme than thermal hysteresis. Experimental results of IR reflow shift are shown below in Figure 20. These results show only shift due to reflow and not mechanical stress.
300 750 850 650 550 PEAK-TO-PEAK NOISE (nV) 380s TP = 260C
Figure 17. Low Frequency Noise Histogram of the LTC6655-2.5
200 160
TL = 217C TS(MAX) = 200C TS = 190C T = 150C RAMP TO 150C
RAMP DOWN
tP 30s tL 130s 40s
150
75 NOISE VOLTAGE (nV/Hz) 120s 0 0 2 6 4 MINUTES
120
8
10
6655 F19
80
Figure 19. Lead-Free Reflow Profile
40 0 8 0.1 1 10 FREQUENCY (Hz) 100
6655 F18
7 6 NUMBER OF UNITS 5 4 3 2 1 0 -0.029 -0.023 -0.017 -0.011 -0.005 OUTPUT VOLTAGE SHIFT DUE TO IR REFLOW (%)
6655 F20
Figure 18. LTC6655-2.5 Low Frequency Noise Spectrum
IR Reflow Shift The mechanical stress of soldering a part to a board can cause the output voltage to shift. Moreover, the heat of an IR reflow or convection soldering oven can also cause the output voltage to shift. The materials that make up a semiconductor device and its package have different rates of expansion and contraction. After a part undergoes the extreme heat of a lead-free IR reflow profile, like the one
Figure 20. Output Voltage Shift Due to IR Reflow
6655fa
LTC6655 Typical applicaTions
Extended Supply Range Reference
4V TO 30V R1 C1 0.1F LTC6655-2.5 VIN VOUT_F SHDN VOUT_S GND
Extended Supply Range Reference
R1 R2 100k 4.7k VOUT C2 10F
6655 TA02
6V TO 80V ON SEMI MMBT5551 0.1F VIN SHDN VOUT_F LTC6655-2.5 VOUT_S GND VOUT C2 10F
6655 TA03
BZX84C12
BZX84C12
C1 0.1F
Boosted Output Current
4V TO 13.2V LTC6655-2.5 SHDN VOUT_F VIN C1 0.1F
6655 TA05
Boosted Output Current
Q1 2N2222 VOUT C2 4.7F IMAX SET BY NPN C3 0.1F VOUT + 1.8V TO 13.2V C1 1F R1 220 C4 1F 2N2905 35mA MAX
GND
VOUT_S
R2 1k
VIN SHDN VOUT_F LTC6655-2.5 VOUT_S GND VOUT C2 10F
6655 TA04
Output Voltage Boost
VIN VOUT + 0.5V TO 13.2V VIN SHDN GND VOUT = VOLTAGE OPTION + 0.002 * R THIS EXAMPLE USES 2.5V AS THE VOLTAGE OPTION VOUT_F LTC6655-2.5 VOUT_S R R = 0k to 1k
6655 TA07
C1 1F
C2 10F
VOUT 2.5V TO 4.5V
FOR R USE A POTENTIOMETER THAT CAN HANDLE 2mA, IS LOW NOISE AND HAS A LOW TEMPERATURE COEFFICIENT
Low Noise Precision Voltage Boost Circuit
VIN VOUT + 0.5V TO 13.2V VIN SHDN GND R3 5k VOUT = VOLTAGE OPTION * (1 + R1/R2) THIS EXAMPLE USES 2.5V AS THE VOLTAGE OPTION VOUT_F LTC6655-2.5 VOUT_S VOUT 5V
C1 1F
VIN LT1677 + + - -
R1 10k R2 10k
C2 10F RLOAD
6655 TA08
FOR R1 AND R2 USE VISHAY TRIMMED RESISTOR ARRAY (VSR144 OR MPM). WITH A PRECISION ARRAY THE MATCHING AND LOW TC WILL HELP PRESERVE LOW DRIFT. R3 = R1||R2
6655fa
LTC6655 Typical applicaTions
Low Noise Statistical Averaging Reference eN = eN/N; Where N is the Number of LTC6655s in Parallel
3V TO 13.2V C1 0.1F
LTC6655-2.5 SHDN VOUT_F VIN GND VOUT_S
R1 32.4 C2 2.7F
VOUT C9 4.7F
LTC6655-2.5 SHDN VOUT_F VIN C3 0.1F GND VOUT_S
R2 32.4 C4 2.7F
LTC6655-2.5 SHDN VOUT_F VIN C5 0.1F GND VOUT_S
R3 32.4 C6 2.7F
LTC6655-2.5 SHDN VOUT_F
6655 TA06a
VIN C7 0.1F
GND
VOUT_S
R4 32.4 C8 2.7F
Low Frequency Noise (0.1Hz to 10Hz) with Four LTC6655-2.5 in Parallel
200nV/ DIV
320nVP-P 0.1Hz to 10Hz
1s/DIV
6655 TA06b
6655fa
LTC6655 pacKage DescripTion
(Reference LTC DWG # 05-08-1660 Rev F)
0.889 (.035 0.127 .005)
MS8 Package 8-Lead Plastic MSOP
5.23 (.206) MIN
3.20 - 3.45 (.126 - .136)
3.00 0.102 (.118 .004) (NOTE 3)
0.42 0.038 (.0165 .0015) TYP
0.65 (.0256) BSC
8
7 65
0.52 (.0205) REF
RECOMMENDED SOLDER PAD LAYOUT
DETAIL "A" 0 - 6 TYP
0.254 (.010)
GAUGE PLANE
4.90 0.152 (.193 .006)
3.00 0.102 (.118 .004) (NOTE 4)
0.53 0.152 (.021 .006)
DETAIL "A"
1 1.10 (.043) MAX
23
4 0.86 (.034) REF
0.18 (.007)
SEATING PLANE
0.22 - 0.38 (.009 - .015) TYP
NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
0.65 (.0256) BSC
0.1016 (.004
0.0508 .002)
MSOP (MS8) 0307 REV F
6655fa
0
LTC6655 reVision hisTory
REV A DATE 02/10 DESCRIPTION Voltage Options Added (1.250, 2.048, 3.000, 3.300, 4.096, 5.000), Reflected Throughout the Data Sheet PAGE NUMBER 1 to 22
6655fa
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.
LTC6655 Typical applicaTion
Low Noise Precision 24-Bit Analog-to-Digital Converter Application
2.5k VREF RREF 400 CH0 CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 CH9 CH10 CH11 CH12 CH13 CH14 CH15 COM REF+ REF- GND GND GND GND GND 5V 7.5V VCC MUXOUTN ADCINN 1nF 50
5k
1/2 LTC6241
- +
RTD
-2.5V MUXOUTP ADCINP 0.01F LTC2449 SDI SCK SDO CS BUSY EXT fO GND GND 0.01F 1nF 50 SPI INTERFACE 2.5k
THERMOCOUPLE
1/2 LTC6241
- +
0.1F
LTC6655 7 VOUT_F 1 6 SHDN VOUT_S 2 VIN GND 3,5,8 GND 4
VREF
10F
6655 TA09
relaTeD parTs
PART NUMBER LT(R)1236 LT1460 LT1461 LT1790 LT6650 LTC6652 LT6660 DESCRIPTION Precision Low Drift Low Noise Reference Micropower Series References Micropower Series Low Dropout Micropower Precision Series References Micropower Reference with Buffer Amplifier Precision Low Drift Low Noise Reference Tiny Micropower Series Reference COMMENTS 0.05% Max, 5ppm/C Max, 1ppm (Peak-to-Peak) Noise 0.075% Max, 10ppm/C Max, 20mA Output Current 0.04% Max, 3ppm/C Max, 50mA Output Current 0.05% Max, 10ppm/C Max, 60mA Supply, SOT23 Package 0.5% Max, 5.6A Supply, SOT23 Package 0.05% Max, 5ppm/C Max, -40C to 125C, MSOP8 0.2% Max, 20ppm/C Max, 20mA Output Current, 2mm x 2mm DFN
6655fa
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 FAX: (408) 434-0507
LT 0210 REV A * PRINTED IN USA
www.linear.com
LINEAR TECHNOLOGY CORPORATION 2009

▲Up To Search▲

Price & Availability of LTC6655

	To Download LTC6655 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .