View LT1027_83134.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

LT1027 Precision 5V Reference
FEATURES
s s
DESCRIPTIO
s s
s s s
Very Low Drift: 2ppm/C Max TC Pin Compatible with LT1021-5, REF-02, (TO-5 and PDIP Packages Only) Output Sources 15mA, Sinks 10mA Excellent Transient Response Suitable for A-to-D Reference Inputs Noise Reduction Pin Excellent Long Term Stability Less Than 1ppm P-P Noise (0.1Hz to 10Hz)
APPLICATIO S
s s s s
The LT (R)1027 is a precision reference with extra-low drift, superior accuracy, excellent line and load regulation and low output impedance at high frequency. This device is intended for use in 12- to 16-bit A-to-D and D-to-A systems where demanding accuracy requirements must be met without the use of power hungry, heated substrate references. The fast settling output recovers quickly from load transients such as those presented by A-to-D converter reference inputs. The LT1027 brings together both outstanding accuracy and temperature coefficient specifications. The LT1027 reference is based on LTC's proprietary advanced subsurface Zener bipolar process which eliminates noise and stability problems associated with surface breakdown devices.
, LTC and LT are registered trademarks of Linear Technology Corporation.
A-to-D and D-to-A Converters Digital Voltmeters Reference Standard Precision Current Source
TYPICAL APPLICATIO
Supplying VREF and VCC to the LTC(R)1290 12-bit ADC Output Voltage
CH0 CH1 CH2 CH3 CH4 CH5 CH6 CH7 COM REF + REF - VCC SCLK ACLK DOUT DIN CS
OUTPUT VOLTAGE (V)
ANALOG INPUTS 8V TO 40V
TO C
LTC1290
VIN
+
2.2F LT1027
VOUT
+
VTRIM 10k 22F AGND
V-
DGND
GND
1027 TA01
U
5.006 5.004 5.002 5.000 4.998 4.996 4.994 -50 -25 50 25 0 TEMPERATURE (C) 75 100
1027 TA02
U
U
1
LT1027 ABSOLUTE AXI U RATI GS
Supply Voltage (VIN) ............................................... 40V Input-Output Voltage Differential ............................ 35V Output to Ground Voltage ......................................... 7V VTRIM to Ground Voltage Positive ................................................................ 5V Negative .......................................................... - 0.3V Output Short-Circuit Duration VIN > 20V ........................................................ 10 sec VIN 20V ................................................... Indefinite
PACKAGE/ORDER I FOR ATIO
TOP VIEW NC* 8 NC* 1 VIN 2 NR 3 5 4 7 NC* 6 VOUT
NC* 1 VIN NR 2 3 4
VTRIM
GND
GND H PACKAGE 8-LEAD TO-5 METAL CAN
TJMAX = 150C, JA = 150C/W, JC = 45C/W
TJMAX = 100C, JA = 130C/W
ORDER PART NUMBER LT1027ACH-5 LT1027BCH-5 LT1027CCH-5 LT1027DCH-5 LT1027ECH-5
ORDER PART NUMBER LT1027BCN8-5 LT1027CCN8-5 LT1027DCN8-5 LT1027ECN8-5
*Connected internally. Do not connect external circuitry to these pins. Consult factory for Industrial and Military grade parts.
The q denotes specifications which apply over the full operating temperature range otherwise specifications are at TA = 25C. VIN = 10V, ILOAD = 0, unless otherwise specified.
SYMBOL VOUT PARAMETER Output Voltage (Note 2) CONDITIONS LT1027A LT1027B, C, D LT1027E LT1027A, B LT1027C LT1027D LT1027E
q q q q
ELECTRICAL CHARACTERISTICS
TCVOUT
Output Voltage Temperature Coefficient (Note 3)
2
U
U
W
WW U
W
(Note 1)
Operating Temperature Range LT1027C ................................................ 0C to 70C LT1027M ......................................... - 55C to 125C Storage Temperature Range All Devices ....................................... - 65C to 150C Lead Temperature (Soldering, 10 sec)................. 300C
TOP VIEW 8 NC*
NR 1 GND 2 VTRIM 3 VOUT 4
TOP VIEW 8 7 6 5 VIN NC* NC* NC*
7 NC* 6 5 N8 PACKAGE 8-LEAD PDIP VOUT VTRIM
S8 PACKAGE 8-LEAD PLASTIC SO
TJMAX = 100C, JA = 180C/W
ORDER PART NUMBER LT1027CCS8-5 LT1027DCS8-5 LT1027ECS8-5 S8 PART MARKING 1027C5 1027D5 1027E5
MIN 4.9990 4.9975 4.9950
TYP
MAX
UNITS V
5.000 5.0010 5.000 5.0025 5.000 5.0050 1 2 2 3 2 3 5 7.5
ppm/C
LT1027
The q denotes specifications which apply over the full operating temperature range otherwise specifications are at TA = 25C. VIN = 10V, ILOAD = 0, unless otherwise specified.
SYMBOL PARAMETER Line Regulation (Note 4) CONDITIONS 8V VIN 10V
q
ELECTRICAL CHARACTERISTICS
MIN
TYP 6 3
MAX 12 25 6 8 6 8 50 100 2.7 3.1
UNITS ppm/V ppm/V ppm/V ppm/V ppm/mA ppm/mA ppm/mA ppm/mA mA mA mV VP-P
10V VIN 40V
q
Load Regulation (Notes 4, 6)
Sourcing Current 0 IOUT 15mA Sinking Current 0 IOUT - 10mA
q q
-8 -10
-3 30 2.2
Supply Current
q
VTRIM Adjust Range en Output Noise (Note 5) Temperature Hysteresis Long Term Stability 0.1Hz f 10Hz 10Hz f 1kHz H package; T = 25C H package
q
30
50 3 2.0 10 20 6.0
VRMS ppm ppm/month
Note 1: Absolute Maximum Ratings are those values beyond which the life of the part may be impaired. Note 2: Output voltage is measured immediately after turn-on. Changes due to chip warm-up are typically less than 0.005%. Note 3: Temperature coefficient is determined by the "box" method in which the maximum VOUT over the temperature range is divided by T. Note 4: Line and load regulation measurements are done on a pulse basis. Output voltage changes due to die temperature change must be taken into account separately. Package thermal resistance is 150C/W for TO-5 (H), 130C/W for PDIP (N8), and 180C/W for plastic SO (SO-8).
Note 5: RMS noise is measured with an 8-pole bandpass filter with a center frequency of 30Hz and a Q of 1.5. The filter output is then rectified and integrated for a fixed time period, resulting in an average, as opposed to RMS voltage. A correction factor is used to convert average to RMS. This value is then used to obtain RMS noise voltage in the 10Hz to 1000Hz frequency band. This test also screens for low frequency "popcorn" noise within the bandwidth of the filter. Consult factory for 100% 0.1Hz to 10Hz noise testing. Note 6: Devices typically exhibit a slight negative DC output impedance of - 0.015. This compensates for PC trace resistance, improving regulation at the load.
TYPICAL PERFOR A CE CHARACTERISTICS
Ripple Rejection
100 120 110
REJECTION (dB)
VIN = 10V OUTPUT IMPEDANCE () 10
OUTPUT VOLTAGE (V)
100 90 80 70 60 50 10 100 1k FREQUENCY (Hz) 10k
1027 G01
UW
Output Impedance vs Frequency
100 5.006 I = 3mA AC ISOURCE = 5mA 5.004 5.002 5.000 4.998 4.996 0.01 10 100 1k 10k FREQUENCY (Hz) 100k 1M
1027 G02
Output Voltage
1
0.1
4.994 -50
-25
50 25 0 TEMPERATURE (C)
75
100
1027 G03
3
LT1027
TYPICAL PERFOR A CE CHARACTERISTICS
Start-Up and Turn-Off (No Load) Start-Up and Turn-Off
2.5
VOUT 1V/DIV
10V VIN
1027 G04
VOUT 1V/DIV
10V VIN RL = 1k, CL = 4.7F
1027 G05
SUPPLY CURRENT (mA)
1s/DIV
Load Regulation
800 500
CHANGE IN OUTPUT VOLTAGE (V)
CHANGE IN OUTPUT VOLTAGE (V)
400 0 -400 -800 -1200 -1600 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 Sink Source IOUT (mA)
1027 G07
300 200 100 0 -100 -200 -300 -400 -500 8 12 16 20 24 28 32 INPUT VOLTAGE (V) 36 40
OUTPUT NOISE DENSITY (nV/Hz)
Output Settling Time (Sourcing)
VOUT 400V/DIV AC COUPLED -10mA LOAD STEP 2s/DIV
1027 G10
10mA
LOAD STEP
2s/DIV
1027 G11
5V/DIV
VOUT 400V/DIV AC COUPLED
4
UW
Quiescent Current
2.0 1.5
1.0
500s/DIV
0.5
0
0
5
10
15 20 25 30 INPUT VOLTAGE (V)
35
40
1027 G06
Line Regulation
200 180 160 140 120 100 80 60 40 20 0 400
Output Noise Voltage Density
CNR = 0 CNR = 1F
10
100 1k FREQUENCY (Hz)
10k
1027 G09
1027 G08
Output Settling Time (Sinking)
0.1Hz to 10Hz Output Noise Filtering = 1 zero at 0.1Hz 2 poles at 10Hz
1sec/DIV
1027 G12
LT1027
APPLICATI S I FOR ATIO U
to approximately 1.2VRMS in a 10Hz to 1kHz bandwidth. Transient response is not affected by this capacitor. Startup settling time will increase to several milliseconds due to the 7k impedance looking into the NR pin. The capacitor must be a low leakage type. Electrolytics are not suitable for this application. Just 100nA leakage current will result in a 150ppm error in output voltage. This pin is the most sensitive pin on the device. For maximum protection a guard ring is recommended. The ring should be driven from a resistive divider from VOUT set to 4.4V (the open-circuit voltage on the NR pin). Transient Response The LT1027 has been optimized for transient response. Settling time is under 2s when an AC-coupled 10mA load transient is applied to the output. The LT1027 achieves fast settling by using a class B NPN/PNP output stage. When sinking current, the device may oscillate with capacitive loads greater than 100pF. The LT1027 is stable with all capacitive loads when at no DC load or when sourcing current, although for best settling time either no output bypass capactor or a 4.7F tantalum unit is recommended. An 0.1F ceramic output capacitor will maximize output ringing and is not recommended. Kelvin Connections Although the LT1027 does not have true force-sense capability, proper hook-up can improve line loss and ground loop problems significantly. Since the ground pin of the LT1027 carries only 2mA, it can be used as a lowside sense line, greatly reducing ground loop problems on the low side of the reference. The VOUT pin should be close to the load or connected via a heavy trace as the resistance of this trace directly affects load regulation. It is important to remember that a 1.22mV drop due to trace resistance is equivalent to a 1LSB error in a 5VFS, 12-bit system. The circuits in Figures 2 and 3 illustrate proper hook-up to minimize errors due to ground loops and line losses. Losses in the output lead can be further reduced by adding a PNP boost transistor if load current is 5mA or higher. R2 can be added to further reduce current in the output sense load.
Effect of Reference Drift on System Accuracy A large portion of the temperature drift error budget in many systems is the system reference voltage. Figure 1 indicates the maximum temperature coefficient allowable if the reference is to contribute no more than 0.5LSB error to the overall system performance. The example shown is a 12-bit system designed to operate over a temperature range from 25C to 65C. Assuming the system calibration is performed at 25C, the temperature span is 40C. It can be seen from the graph that the temperature coefficient of the reference must be no worse than 3ppm/C if it is to contribute less than 0.5LSB error. For this reason, the LT1027 has been optimized for low drift.
MAXIMUM TEMPERATURE COEFFICIENT FOR 0.5LSB ERROR (ppm/C)
100 8-BIT
10-BIT 10 12-BIT 14-BIT
1.0 0 10 20 30 40 50 60 70 80 90 100 TEMPERATURE SPAN (C)
1027 AI01
Figure 1. Maximum Allowable Reference Drift
Trimming Output Voltage The LT1027 has an adjustment pin for trimming output voltage. The impedance of the VADJ pin is about 20k with an open-circuit voltage of 2.5V. A 30mV guaranteed trim range is achievable by tying the VADJ pin to the wiper of a 10k potentiometer connecting between the output and ground. Trimming output voltage does not affect the TC of the device. Noise Reduction The positive input of the internal scaling amplifier is brought out as the Noise Reduction (NR) pin. Connecting a 1F Mylar capacitor between this pin and ground will reduce the wideband noise of the LT1027 from 2.0VRMS
W
U
UO
5
LT1027
APPLICATI S I FOR ATIO U
INPUT R1 91
KEEP THIS LINE RESISTANCE LOW INPUT IN LT1027 OUT
GND
GROUND RETURN
1027 F02
Figure 2. Standard Hook-Up
GROUND RETURN
1027 F03
TYPICAL APPLICATIONS
10V Reference
VIN
VIN VOUT 7 8
IN OUT LT1027 VTRIM GND 5k
+
LT1097 10.00V OUTPUT
-
5k*
5k* * 0.1% METAL FILM
1027 TA03
CMOS LOGIC GATE** 1N914 1N914 fIN 2kHz* 8.5V
C1 5F*
*FOR HIGHER FREQUENCIES C1 AND C2 MAY BE DECREASED **PARALLEL GATES FOR HIGHER REFERENCE CURRENT LOADING
6
+
W
U
U
UO
2N4403
+
LOAD
IN
LT1027
OUT R2* 2.4k
+
4.7F
LOAD
GND
*OPTIONAL-REDUCES CURRENT IN OUTPUT SENSE LEAD
Figure 3. Driving Higher Load Currents
10V Reference
VIN 1F 1F 12 GND 13 16 11
LT1027
OUT
LTC1043 14 17
0.01F
1027 TA04
Operating 5V Reference from 5V Supply
5V LOGIC SUPPLY
IN
LT1027
OUT
5V REFERENCE
+
C2 5F*
GND
1027 TA05
LT1027
EQUIVALE T SCHE ATIC
VIN
NR VADJ
GND
PACKAGE DESCRIPTIO
SEATING PLANE 0.010 - 0.045* (0.254 - 1.143) 0.016 - 0.021** (0.406 - 0.533)
45TYP 0.028 - 0.034 (0.711 - 0.864)
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 circuits as described herein will not infringe on existing patent rights.
U
W
U
VOUT
1027 ES
OUTPUT CURRENT LIMIT AND BIAS CIRCUITS NOT SHOWN
Dimensions in inches (millimeters) unless otherwise noted. H Package 8-Lead TO-5 Metal Can (0.230 PCD)
(LTC DWG # 05-08-1321)
0.335 - 0.370 (8.509 - 9.398) DIA 0.305 - 0.335 (7.747 - 8.509) 0.040 (1.016) MAX 0.050 (1.270) MAX GAUGE PLANE 0.165 - 0.185 (4.191 - 4.699) REFERENCE PLANE 0.500 - 0.750 (12.700 - 19.050)
0.027 - 0.045 (0.686 - 1.143) PIN 1
0.230 (5.842) TYP
0.110 - 0.160 (2.794 - 4.064) INSULATING STANDOFF
*LEAD DIAMETER IS UNCONTROLLED BETWEEN THE REFERENCE PLANE AND 0.045" BELOW THE REFERENCE PLANE 0.016 - 0.024 **FOR SOLDER DIP LEAD FINISH, LEAD DIAMETER IS (0.406 - 0.610)
H8 (TO-5) 0.230 PCD 1197
7
LT1027
PACKAGE DESCRIPTIO
0.300 - 0.325 (7.620 - 8.255)
0.009 - 0.015 (0.229 - 0.381)
0.065 (1.651) TYP 0.125 (3.175) 0.020 MIN (0.508) MIN 0.018 0.003 (0.457 0.076)
(
+0.035 0.325 -0.015 8.255 +0.889 -0.381
)
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 0- 8 TYP
0.053 - 0.069 (1.346 - 1.752)
0.014 - 0.019 (0.355 - 0.483) TYP *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
0.016 - 0.050 (0.406 - 1.270)
RELATED PARTS
PART NUMBER LT1019 LT1021 LT1236 LT1460 LT1461 LT1798 DESCRIPTION Precision Series Bandgap Reference, 0.05%, 5ppm/C Drift Precision Buried Zener Diode Reference, 0.5%, 5ppm/C Drift Precision Series Reference, 0.05%, 5ppm/C Drift Micropower Precision Series Bandgap Reference, 0.075%, 10ppm/C Drift Low Dropout 3ppm/C Drift, 0.04% Series Reference Low Dropout, Micropower Reference COMMENTS 2.5V, 4.5V, 5V, 10V Outputs; Industrial, Military Grades Available 5V, 7V, 10V Outputs; 8-Pin PDIP, SO, TO-5 Packages; Military Grades Available 5V, 10V Outputs; 8-Pin PDIP, SO Packages; Industrial Grade Available 2.5V, 5V, 10V Outputs; 8-Pin PDIP, SO, MSOP; TO-92 and SOT-23 Packages 2.5V, SO-8 Package 2.5V, 3V, 4.096V, 5V, Adjustable in SO-8
8
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 q FAX: (408) 434-0507 q www.linear-tech.com
U
Dimensions in inches (millimeters) unless otherwise noted. N8 Package 8-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
0.400* (10.160) MAX 8 7 6 5
0.045 - 0.065 (1.143 - 1.651)
0.130 0.005 (3.302 0.127)
0.255 0.015* (6.477 0.381)
1
2
3
4
N8 1098
0.100 (2.54) BSC
S8 Package 8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 - 0.197* (4.801 - 5.004) 8 0.004 - 0.010 (0.101 - 0.254) 0.228 - 0.244 (5.791 - 6.197) 0.150 - 0.157** (3.810 - 3.988) 7 6 5
0.050 (1.270) BSC
SO8 1298
1
2
3
4
1027fb LT/TP 1299 2K REV B * PRINTED IN USA
(c) LINEAR TECHNOLOGY CORPORATION 1992

▲Up To Search▲

Price & Availability of LT1027

	To Download LT1027 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .