CIRRUS VRE3050A

VRE3050
VRE3050
P r o d u c t IInnnnoovvaa t i o n FFr roomm
Precision Voltage Reference
Features
DESCRIPTION
The VRE3050 is a low cost, high precision 5 V reference that operates from +10 V. The device features
a buried zener for low noise and excellent long term
stability. Packaged in an 8-pin SMT, the device is ideal
for high resolution data conversion systems.
♦ +5 V Output, ± 0.5 mV (.01%)
♦ Temperature Drift: 0.6 ppm/ºC
♦ Low Noise: 3 μVP-P (0.1Hz-10Hz)
♦ Low Thermal Hysterisis: 1 ppm Typical
♦ ±15mA Output Source and Sink Current
♦ Excellent Line Regulation: 5 ppm/V Typical
♦ Optional Noise Reduction and Voltage Trim
♦ Industry Standard Pinout: 8-pin Surface Mount
Package
The device provides ultrastable +5 V output with ±0.5
mV (.01%) initial accuracy and a temperature coefficient of 0.6 ppm/°C. This improvement in accuracy is
made possible by a unique, patented multipoint laser
compensation technique. Significant improvements
have been made in other performance parameters as
well, including initial accuracy, warm-up drift, line regulation, and long-term stability, making the VRE3050
series the most accurate reference available.
Applications
The VRE3050 is recommended for use as a reference for 14, 16, or 18 bit data converters which
require an external precision reference. The device is also ideal for calibrating scale factor on
high resolution data converters. The VRE3050
offers superior performance over monolithic references.
For enhanced performance, the VRE3050 has an external trim option for users who want less than 0.01%
initial error. For ultra low noise applications, an external
capacitor can be attached between the noise reduction
pin and the ground pin.
Figure 1. BLOCK DIAGRAM
8
2
+
6
-
R1
R4
R2
5
R3
4
Selection Guide
Model
VRE3050A
VRE3050B
VRE3050C
VRE3050J
VRE3050K
VRE3050L
VRE3050DS
Initial Error Temp. Coeff.
(mV)
(ppm/ºC)
±0.5
±0.8
±1.0
±0.5
±0.8
±1.0
http://www.cirrus.com
0.6
1.0
2.0
0.6
1.0
2.0
Temp. Range
(ºC)
0ºC to +70ºC
0ºC to +70ºC
0ºC to +70ºC
-40ºC to +85ºC
-40ºC to +85ºC
-40ºC to +85ºC
Copyright
© Cirrus
Logic, Inc. 2009
(All Rights Reserved)
8-pin Surface Mount
Package Style GF
MAR 2009
APEX − VRE3050DSREVF
VRE3050
P r o d u c t I n n o v a t i o nF r o m
1. Characteristics and Specifications
ABSOLUTE MAXIMUM RATINGS
Power Supply............................ -0.3V to +40V
OUT, TRIM................................. -0.3V to +12V
NR............................................... -0.3V to +6V
Operating Temp. (A,B,C)............ 0ºC to +70ºC
Operating Temp. (J,K,L).......... -40ºC to +85ºC
Out Short Circuit to GND Duration (VIN< 12V)............ Continuous
Out Short Circuit to GND Duration (VIN< 40V)......................5 sec
Out Short Circuit to IN Duration (VIN< 12V)................ Continuous
Continuous Power Dissipation (TA = +70ºC)..................... 300mW
Storage Temperature.......................................... -65ºC to +150ºC
Lead Temperature (soldering,10 sec)............................... +250ºC
ELECTRICAL Specifications
Vps =±15V, T = +25ºC, RL = 10KΩ Unless Otherwise Noted.
Parameter
Symbol
Input Voltage
Conditions
Min
Typ
Max
Units
VRE3050A/J
+36
V
+2.4995
+5.0000
+5.0005
VRE3050B/K
+2.4992
+5.0000
+5.0008
VRE3050C/L
+2.4990
+5.0000
+5.0010
VRE3050A/J
0.3
0.6
VRE3050B/K
0.5
1.0
VRE3050C/L
1.0
2.0
VIN
Output Voltage (Note 1)
+8
VOUT
V
Output Voltage
Temperature Coefficient
(Note 2)
TCVOUT
Trim Adjustment Range
∆VOUT
Figure 3
±5.0
TON
To 0.01% of final value
2.0
µs
0.1Hz < f < 10Hz
3.0
µVp-p
10Hz < f < 1kHz
2.5
Note 4
1
ppm
6
ppm/1000hrs.
Turn-On Settling Time
Output Noise Voltage
en
Temperature Hysterisis
Long Term Stability
∆VOUT/t
Supply Current
IIN
Load Regualtion (Note 3) ∆VOUT/ ∆IOUT
Line Regulation
(Note 3)
mV
5.0
3.5
4.0
Sourcing: 0mA ≤ IOUT ≤ 15mA
8
12
Sinking: -15mA ≤ IOUT ≤ 0mA
8
12
8V ≤ VIN ≤ 10V
25
35
10V ≤ VIN ≤ 18V
5
10
∆VOUT/ ∆VIN
ppm/ºC
µVRMS
mA
ppm/mA
ppm/V
NOTES:
1. The specified values are without external trim.
2. The temperature coefficient is determined by the box method. See discussion on temperature performance.
3. Line and load regulation are measured with pulses and do not include voltage changes due to temperature.
4. Hysterisis over the operating temperature range.
VRE3050DS
VRE3050
P r o d u c t I n n o v a t i o nF r o m
2. TYPICAL PERFORMANCE CURVES
1.00
1.00
1.00
0.75
0.75
0.75
0.50
0.50
0.50
0
-0.25
Low
Loer
wer Limi
Lim itt
Up per
0.25
0
-0.25
Lo wer
-0.50
-0.75
Lim it
0
20
30
40
50
60
-1.00
70
0
20
Temperature (oC)
VRE3050A
VOUT vs. TEMPERATURE
40
30
50
70
-1.00
2.0
1.0
1.0
1.0
-1.5
-2.0
-50 -25
0
Lim it
25
50
75 100
Up per
0.5
0
-0.5
50
60
Lo wer
Lim it
-1.0
-1.5
-2.0
-50 -25
25
50
75 100
Lim it
Lo wer
Lim it
0
-1.5
-2.0
-50 -25
0
Up per
70
-0.5
Temperature (oC)
VRE3050K
SUPPLY CURRENT
VS. SUPPLY VOLTAGE
40
0.5
-1.0
Temperature (oC)
VRE3050J
0
25
50
75 100
Temperature (oC)
VRE3050L
QUIESCENT CURRENT VS. TEMP
OUTPUT IMPEDIANCE
VS. FREQUENCY
Quiescent Current (mA)
5.0
4.0
3.0
Output Impediance ( Ω)
8.0
6.0
0
Lim it
∆Vout (mV)
∆Vout (mV)
Lo wer
-1.0
30
VOUT vs. TEMPERATURE
1.5
-0.5
20
VOUT vs. TEMPERATURE
2.0
0
0
Temperature (oC)
VRE3050C
1.5
Lim it
Lim it
Temperature (oC)
VRE3050B
1.5
Up per
Lo wer
0
2.0
0.5
Lim it
-0.25
-0.50
60
Up per
0.25
-0.75
-0.75
-1.00
∆Vout (mV)
Lim it
∆Vout (mV)
Uper
per LiLim
it
Upp
mit
0.25
-0.50
Supply Current (mA)
VOUT vs. TEMPERATURE
VOUT vs. TEMPERATURE
∆Vout (mV)
∆Vout (mV)
VOUT vs. TEMPERATURE
6.0
4.0
2.0
0
0
5 10 15 20 25 30 35 40
-50
Supply Voltage (V)
VRE3050DS
0
50
Temperature (oC)
100
Frequency (Hz)
VRE3050
JUNCTION TEMP. RISE VS.
OUTPUT CURRENT
30
20
V
cc
10
=
V
10
0
0
4
2
6
100
8
RIPPLE REJECTION
Vs. FREQUENCY(CNR=0µF)
0V
80
B
70
60
10
10
100
10k
1 µs/div
CHANGE IN OUTPUT VOLTAGE
VS. OUTPUT CURRENT
100
CHANGE IN OUTPUT VOLTAGE
VS. INPUT VOLTAGE
400
60
40
1k
10k
60
300
50
200
40
Vout (ppm)
80
Vout (µV)
Output Noise Density (nV/√Hz)
1k
A: Vin, 10V/div
B: Vout, 1V/div
Frequency (Hz)
OUTPUT NOISE-VOLTAGE
DENSITY vs. FREQUENCY
100
+10V
90
Output Current (mA)
20
10
TURN-ON AND TURN-OFF
TRANSIENT RESPONSE
A
Ripple Rejection (dB)
40
Junction Temperature
Rise Above Ambient (oC)
P r o d u c t I n n o v a t i o nF r o m
100
0
-100
30
20
10
-200
0
-300
-10
-400
0 2
4
6
-20
8 10 12 14 16
9 10 11 12 13 14 15 16
Vin(V)
Iout(mA)
Frequency (Hz)
0
∆Vout, 1µV/Div
0.1Hz to 10Hz Noise
1 Sec/Div
VRE3050DS
VRE3050
P r o d u c t I n n o v a t i o nF r o m
3. THEORY OF OPERATION
The following discussion refers to the block diagram in Figure 1. A FET current source is used to bias a 6.3 V zener
diode. The zener voltage is divided by the resistor network R1 and R2. This voltage is then applied to the noninverting input of the operational amplifier which amplifies the voltage to produce a 5 V output. The gain is determined by
the resistor networks R3 and R4: G=1 + R4/R3. The 6.3 V zener diode is used because it is the most stable diode
over time and temperature.
The current source provides a closely regulated zener current, which determines the slope of the references’ voltage vs. temperature function. By trimming the zener current a lower drift over temperature can be achieved. But
since the voltage vs. temperature function is nonlinear this compensation technique is not well suited for wide temperature ranges.
A nonlinear compensation network of thermistors and resistors that is used in the VRE series voltage references.
This proprietary network eliminates most of the nonlinearity in the voltage vs. temperature function. By adjusting the
slope, a very stable voltage is produced over wide temperature ranges.
This network is less than 2% of the overall network resistance so it has a negligible effect on long term stability. The
proper connection of the VRE3050 series voltage references with the optional trim resistor for initial error and the
optional capacitor for noise reduction is shown below.
EXTERNAL CONNECTIONS
+ VIN
2
Optional Noise
Reduction
Capacitor
CN 1µF
8
+ VOUT
6
VRE3050
4
10kΩ
5
Optional Fine
Trim Adjustment
PIN DESCRIPTION
1, 3, 7
N. C.
Internally connected. Do not use
2
VIN
Positive power supply input
4
GND
Ground
5
TRIM
External trim input. Leave open if not
used.
6
OUT
Voltage reference output
8
NR
Noise Reduction
4. BASIC CIRCUIT CONNECTION
To achieve the specified performance, pay careful attention to the layout. A low resistance star configuration will
reduce voltage errors, noise pickup, and noise coupled from the power supply. Commons should be connected to
a single point to minimize interconnect resistances.
VRE3050DS
VRE3050
P r o d u c t I n n o v a t i o nF r o m
Figure 3.
10000
Reference TC (ppm/ºC
1000
100
8 BIT
10 BIT
10
12 BIT
1
14 BIT
16 BIT
0.1
18 BIT
0.01
20 BIT
1
10
100
Reference TC vs. ∆T change from 25°C for 1 LSB change
5. TEMPERATURE PERFORMANCE
The VRE3050 is designed for applications where the initial error at room temperature and drift over temperature are
important to the user. For many instrument manufacturers, a voltage reference with a temperature coefficient less
than 1 ppm/°C makes it possible to not perform a system temperature calibration, a slow and costly process.
Of the three TC specification methods (slope, butterfly, and box), the box method is most commonly used. A box
is formed by the min/max limits for the nominal output voltage over the operating temperature range. The equation
follows:
VMAX – VMIN
T.C. =
x 106
VNOMINAL x (TMAX – TMIN)
This method corresponds more accurately to the method of test and provides a closer estimate of actual error than
the other methods. The box method guarantees limits for the temperature error but does not specify the exact shape
and slope of the device under test.
A designer who needs a 14-bit accurate data acquisition system over the industrial temperature range (-40°C to
+85°C), will need a voltage reference with a temperature coefficient (TC) of 1 ppm/°C if the reference is allowed
to contribute an error equivalent to 1LSB. For 1/2LSB equivalent error from the reference you would need a voltage reference with a temperature coefficient of 0.5 ppm/°C. Figure 4 shows the required reference TC vs. delta T
change from 25°C for resolution ranging from 8 bits to 20 bits.
6. THERMAL HYSTERISIS
A change in output voltage as a result of a temperature change. When references experience a temperature change
and return to the initial temperature, they do not always have the same initial voltage. Thermal hysterisis is difficult to
correct and is a major error source in systems that experience temperature changes greater than 25°C. Reference
vendors are starting to include this important specification in their datasheets.
PIN CONFIGURATION
N/C
1
+VIN
2
N/C
3
GND
4
VRE3050
TOP
VIEW
8
NOISE
REDUCTION
7
N/C
6
VOUT
5
TRIM
VRE3050DS
VRE3050
P r o d u c t I n n o v a t i o nF r o m
Contacting Cirrus Logic Support
For all Apex Precision Power product questions and inquiries, call toll free 800-546-2739 in North America.
For inquiries via email, please contact [email protected]
International customers can also request support by contacting their local Cirrus Logic Sales Representative.
To find the one nearest to you, go to www.cirrus.com
IMPORTANT NOTICE
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VRE3050DS