Precision Micropower,
Low Dropout Voltage Reference
REF191-EP
Enhanced Product
PIN CONFIGURATION DIAGRAM
Temperature coefficient: 5 ppm/°C maximum
High output current: 30 mA
Low supply current: 50 µA maximum
Initial accuracy: 2.050 V maximum
Sleep mode: 15 µA maximum
Low dropout voltage
Load regulation: 4 ppm/mA typical at TA = 25°C
Line regulation: 2 ppm/V typical at TA = 25°C
Short-circuit protection
REF191-EP
TP 1
8
NIC
VS 2
7
NIC
6
OUTPUT
5
TP
TOP VIEW
SLEEP 3 (Not to Scale)
GND 4
NOTES
1. NIC = NO INTERNAL CONNECTION.
2. TP PINS ARE FACTORY TEST
POINTS, NO USER CONNECTION.
17250-001
FEATURES
Figure 1.
ENHANCED PRODUCT FEATURES
Supports defense and aerospace applications (AQEC standard)
Military temperature range: −55°C to +125°C
Controlled manufacturing baseline
1 assembly/test site
1 fabrication site
Product change notification
Qualification data available on request
APPLICATIONS
Portable instruments
ADCs and DACs
Smart sensors
Solar powered applications
Loop current powered instruments
GENERAL DESCRIPTION
The REF191-EP precision band gap voltage reference uses a
proprietary temperature drift curvature correction circuit and
laser trimming of highly stable, thin film resistors to achieve a
very low temperature coefficient and high initial accuracy.
The REF191-EP is a micropower, low dropout voltage device,
providing stable output voltage from supplies with low headroom
and consuming less than 50 µA of supply current. In sleep mode,
which is enabled by applying a low transistor to transistor logic
(TTL) or complementary metal-oxide semiconductor (CMOS)
level to the SLEEP pin, the output is turned off and supply
current is further reduced to less than 15 µA.
The REF191-EP is available in an 8-lead SOIC package.
Pin 1 and Pin 5 (TP) are reserved for in package Zener zaps. To
achieve the highest level of accuracy at the output, the Zener
zapping technique is used to trim the output voltage. Because
each unit may require a different amount of adjustment, the
resistance value at the test pins varies widely from pin to pin
and from device to device. Leave Pin 1 and Pin 5 unconnected.
Additional application and technical information can be found
in the REF19x Series data sheet.
The REF191-EP reference is specified over the full military
temperature range (−55°C to +125°C).
Rev. 0
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Tel: 781.329.4700
©2020 Analog Devices, Inc. All rights reserved.
Technical Support
www.analog.com
REF191-EP
Enhanced Product
TABLE OF CONTENTS
Features .............................................................................................. 1
Absolute Maximum Ratings ............................................................4
Enhanced Product Features ............................................................ 1
Thermal Resistance .......................................................................4
Applications ....................................................................................... 1
ESD Caution...................................................................................4
Pin Configuration Diagram ............................................................ 1
Typical Performance Characteristics ..............................................5
General Description ......................................................................... 1
Outline Dimensions ..........................................................................6
Revision History ............................................................................... 2
Ordering Guide .............................................................................6
Specifications..................................................................................... 3
REVISION HISTORY
2/2020—Revision 0: Initial Version
Rev. 0 | Page 2 of 6
Enhanced Product
REF191-EP
SPECIFICATIONS
At VS = 3.3 V, TA = 25°C, unless otherwise noted.
Table 1.
Parameter
INITIAL ACCURACY1
REGULATION2
Line
Load
DROPOUT VOLTAGE
Symbol
VO
Test Conditions/Comments
Output current (IOUT) = 0 mA
ΔVO/ΔVIN
ΔVO/ΔVLOAD
VS − VO
LONG-TERM STABILITY3
NOISE VOLTAGE
DVO
eN
3.0 V ≤ VS ≤ 15 V, IOUT = 0 mA
VS = 5.0 V, 0 mA ≤ IOUT ≤ 30 mA
VS = 3.0 V, load current (ILOAD) = 2 mA
VS = 3.3 V, ILOAD = 10 mA
VS = 3.6 V, ILOAD = 30 mA
1000 hours at 125°C
0.1 Hz to 10 Hz
1
2
3
Min
2.046
Typ
2.048
Max
2.050
Unit
V
2
4
4
11
0.95
1.25
1.55
ppm/V
ppm/mA
V
V
V
mV
µV p-p
1.2
20
Initial accuracy does not include shift due to solder heat effect.
Line and load regulation specifications include the effect of self heating.
Long-term stability specification is noncumulative. The drift in subsequent 1000-hour periods is significantly lower than in the first 1000-hour period.
At VS = 3.3 V, −40°C ≤ TA ≤ +125°C, unless otherwise noted.
Table 2.
Parameter
TEMPERATURE COEFFICIENT1, 2
REGULATION3
Line
Load
DROPOUT VOLTAGE
SLEEP PIN
Logic High Input Voltage
Logic High Input Current
Logic Low Input Voltage
Logic Low Input Current
SUPPLY CURRENT
Sleep Mode
Symbol
TCVO
Test Conditions/Comments
IOUT = 0 mA
ΔVO/ΔVIN
ΔVO/ΔVLOAD
VS − VO
3.0 V ≤ VS ≤ 15 V, IOUT = 0 mA
VS = 5.0 V, 0 mA ≤ IOUT ≤ 20 mA
VS = 3.0 V, ILOAD = 2 mA
VS = 3.3 V, ILOAD = 10 mA
VS = 3.6 V, ILOAD = 20 mA
VH
IH
VL
IL
Min
Typ
2
Max
5
Unit
ppm/°C
5
5
10
15
0.95
1.25
1.55
ppm/V
ppm/mA
V
V
V
−8
0.8
−8
50
15
V
µA
V
µA
µA
µA
2.4
No load
No load
2
For proper operation, a 1 µF capacitor is required between the output pin and the GND pin of the device.
TCVO is defined as the ratio of the output voltage change (between the maximum output voltage (VMAX) and the minimum output voltage (VMIN)) with temperature
variation to the specified temperature range, expressed in ppm/°C.
3
Line and load regulation specifications include the effect of self heating.
1
TCVO = (VMAX − VMIN)/VO(TMAX − TMIN)
At VS = 3.3 V, −55°C ≤ TA ≤ +125°C, unless otherwise noted.
Table 3.
Parameter
TEMPERATURE COEFFICIENT1, 2
REGULATION3
Line
Load
Symbol
TCVO
Test Conditions/Comments
IOUT = 0 mA
ΔVO/ΔVIN
ΔVO/ΔVLOAD
DROPOUT VOLTAGE
VS − VO
3.0 V ≤ VS ≤ 15 V, IOUT = 0 mA
VS = 5.0 V, 0 mA ≤ IOUT ≤ 25 mA, TA = −55°C
VS = 5.0 V, 0 mA ≤ IOUT ≤ 20 mA, TA = 125°C
VS = 3.3 V, ILOAD = 10 mA
VS = 3.6 V, ILOAD = 20 mA
Min
Typ
2
10
10
10
Max
15
15
1.25
1.55
Unit
ppm/°C
ppm/V
ppm/mA
ppm/mA
V
V
2
For proper operation, a 1 µF capacitor is required between the output pin and the GND pin of the device.
TCVO is defined as the ratio of the output voltage change (between the maximum output voltage (VMAX) and the minimum output voltage (VMIN)) with temperature
variation to the specified temperature range, expressed in ppm/°C.
3
Line and load regulation specifications include the effect of self heating.
1
TCVO = (VMAX − VMIN)/VO(TMAX − TMIN)
Rev. 0 | Page 3 of 6
REF191-EP
Enhanced Product
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 4.
Parameter
Supply Voltage
Output to GND
Output to GND Short-Circuit Duration
Temperature Ranges
Storage
Operating
Junction
Lead Temperature (Soldering 60 sec)
Rating
−0.3 V to +18 V
−0.3 V to VS + 0.3 V
Indefinite
−65°C to +150°C
−55°C to +125°C
−65°C to +150°C
260°C
Thermal performance is directly linked to printed circuit board
(PCB) design and operating environment. Careful attention to
PCB thermal design is required.
θJA is the natural convection junction to ambient thermal
resistance measured in a one cubic foot sealed enclosure. θJC is
the junction to case thermal resistance.
Table 5. Thermal Resistance
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
Package Type1
R-8
1
θJA
158
θJC
43
Unit
°C/W
Thermal impedance simulated values are based on JEDEC specifications. Use
these values in compliance with JESD51-12.
ESD CAUTION
Rev. 0 | Page 4 of 6
Enhanced Product
REF191-EP
TYPICAL PERFORMANCE CHARACTERISTICS
2.051
–2.0
3 TYPICAL PARTS
VS = 3.3V
–1.8
–1.6
2.049
2.048
2.047
–1.4
–1.2
–1.0
–0.8
–0.6
VL
–0.4
2.046
–35
–15
5
25
45
65
85
105
17250-002
–0.2
2.045
–55
125
TEMPERATURE (°C)
Figure 2. Output Voltage vs. Temperature
NORMAL MODE
25
20
15
10
0
–55
SLEEP MODE
–35
–15
5
25
45
65
85
TEMPERATURE (°C)
105
125
17250-003
SUPPLY CURRENT (µA)
35
5
VH
–35
–15
5
25
45
65
85
TEMPERATURE (°C)
Figure 4. SLEEP Pin Current vs. Temperature
40
30
0
–55
Figure 3. Supply Current vs. Temperature
Rev. 0 | Page 5 of 6
105
125
17250-004
SLEEP PIN CURRENT (µA)
OUTPUT VOLTAGE (V)
2.050
REF191-EP
Enhanced Product
OUTLINE DIMENSIONS
5.00 (0.1968)
4.80 (0.1890)
1
5
6.20 (0.2441)
5.80 (0.2284)
4
1.27 (0.0500)
BSC
0.25 (0.0098)
0.10 (0.0040)
COPLANARITY
0.10
SEATING
PLANE
0.50 (0.0196)
0.25 (0.0099)
1.75 (0.0688)
1.35 (0.0532)
0.51 (0.0201)
0.31 (0.0122)
45°
8°
0°
0.25 (0.0098)
0.17 (0.0067)
1.27 (0.0500)
0.40 (0.0157)
COMPLIANT TO JEDEC STANDARDS MS-012-AA
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
012407-A
8
4.00 (0.1574)
3.80 (0.1497)
Figure 5. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
S-Suffix (R-8)
Dimensions shown in millimeters and (inches)
ORDERING GUIDE
Model1
REF191TRZ-EP
REF191TRZ-EP-RL
1
Temperature Range
−55°C to +125°C
−55°C to +125°C
Package Description
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
Z = RoHS Compliant Part.
©2020 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D17250-2/20(0)
Rev. 0 | Page 6 of 6
Package Option
R-8
R-8
