August, 2004 1 M9999-081604
LM4040/4041 Micrel
LM4040/4041
Precision Micropower Shunt Voltage Reference
General Description
Ideal for space critical applications, the LM4040 and LM4041
precision voltage references are available in the subminia-
ture (3mm × 1.3mm) SOT-23 surface-mount package.
The LM4040 is the available in fixed reverse breakdown
voltages of 2.500V, 4.096V and 5.000V. The LM4041 is
available with a fixed 1.225V or an adjustable reverse break-
down voltage.
The minimum operating current ranges from 60µA for the
LM4041-1.2 to 74µA for the LM4040-5.0. LM4040 versions
have a maximum operating current of 15mA. LM4041 ver-
sions have a maximum operating current of 12mA.
The LM4040 and LM4041 have bandgap reference tempera-
ture drift curvature correction and low dynamic impedance,
ensuring stable reverse breakdown voltage accuracy over a
wide range of operating temperatures and currents.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
Features
• Small SOT-23 package
• No output capacitor required
• Tolerates capacitive loads
• Fixed reverse breakdown voltages of 1.225, 2.500V,
4.096V and 5.000V
• Adjustable reverse breakdown version
• Contact Micrel for parts with extended temperature
range.
Key Specifications
• Output voltage tolerance .............................±0.1% (max)
• Low output noise (10Hz to 100Hz)
LM4040 ................................................ 35µVRMS (typ)
LM4041 ................................................ 20µVRMS (typ)
• Wide operating current range
LM4040 ................................................ 60µA to 15mA
LM4041 ................................................ 60µA to 12mA
• Industrial temperature range ..................–40°C to +85°C
• Low temperature coefficient ................100ppm/°C (max)
Applications
• Battery-powered equipment
• Data acquisition systems
• Instrumentation
• Process control
• Energy management
• Product testing
• Automotive electronics
• Precision audio components
Typical Applications
VS
RS
VR
LM4041
Adjustable
R1
R2
VO
V
S
R
S
V
R
I
Q
+ I
L
I
Q
I
L
LM4040
LM4041
V
O
Figure 2. LM4041 Adjustable
Shunt Regulator Application
Figure 1. LM4040, LM4041 Fixed
Shunt Regulator Application
VO = 1.233 (R2/R1 + 1)
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
LM4040/4041 Micrel
M9999-081604 2 August, 2004
Part Number Voltage Accuracy,
Temp. Coefficient
LM4041CIM3-1.2 1.225V ±0.5%, 100ppm/°C
LM4041DIM3-1.2 1.225V ±1.0%, 150ppm/°C
LM4041CIM3-ADJ 1.24V to 10V ±0.5%, 100ppm/°C
LM4041DIM3-ADJ 1.24V to 10V ±1.0%, 150ppm/°C
LM4041CYM3-1.2 1.225V ±0.5%, 100ppm/°C
Pb free
LM4041CYM3-ADJ 1.24V to 10V ±0.5%, 100ppm/°C
Pb free
LM4041DYM3-1.2 1.225V ±0.5%, 150ppm/°C
Pb free
Pin Configuration
1
2
3 –
FB
+
Adjustable Version
SOT-23 (M3) Package
Top View
Fixed Version
SOT-23 (M3) Package
Top View
1
2
3
+
–
Pin 3 must float or
be connected to pin 2.
Part Number Voltage Accuracy,
Temp. Coefficient
LM4040CIM3-2.5 2.500V ±0.5%, 100ppm/°C
LM4040DIM3-2.5 2.500V ±1.0%, 150ppm/°C
LM4040CIM3-4.1 4.096V ±0.5%, 100ppm/°C
LM4040DIM3-4.1 4.096V ±1.0%, 150ppm/°C
LM4040CIM3-5.0 5.000V ±0.5%, 100ppm/°C
LM4040DIM3-5.0 5.000V ±1.0%, 150ppm/°C
LM4040CYM3-2.5 2.500V ±1.0%, 100ppm/°C
Pb free
LM4040CYM3-5.0 5.000V ±1.0%, 100ppm/°C
Pb free
Example Field Code
_ _ C 3rd Character
C = ±0.5%
D = ±1.0%
X=
±0.5% Pb-Free
Y=
±1.0% Pb-Free
Example Field Code
_ 2 _ 2nd Character 1 = 1.225V
2 = 2.500V
4 = 4.096V
5 = 5.000V
A = Adjustable
Example: R2C represents
Reference,
2.500V,
±
0.5%
(LM4040CIM3-2.5)
Example: Y1C represents
Pb-Free,
1.225V,
±
0.5%
(LM4040CYM3-1.2) Note: If 3rd character is omitted, container will
indicate tolerance.
SOT-23 Package Markings
Example Field Code
R _ _ 1st Character R = Reference
Y _ _ 1st Character Y = Pb-Free
Ordering Information
August, 2004 3 M9999-081604
LM4040/4041 Micrel
Absolute Maximum Ratings
Reverse Current.........................................................20mA
Forward Current .........................................................10mA
Maximum Output Voltage
LM4041-Adjustable ...................................................15V
Power Dissipation at TA = 25°C (Note 2)................306mW
Storage Temperature ...............................–65°C to +150°C
Lead Temperature
Vapor phase (60 seconds) .............................. +215°C
Infrared (15 seconds) ...................................... +220°C
ESD Susceptibility
Human Body Model (Note 3) ................................2kV
Machine Model (Note 3)......................................200V
Operating Ratings (Notes 1 and 2)
Temperature Range
(TMIN ≤ TA ≤ TMAX)..........................–40°C ≤ TA ≤ +85°C
Reverse Current
LM4040-2.5 .......................................... 60µA to 15mA
LM4040-4.1 .......................................... 68µA to 15mA
LM4040-5.0 .......................................... 74µA to 15mA
LM4041-1.2 .......................................... 60µA to 12mA
LM4041-ADJ ........................................ 60µA to 12mA
Output Voltage Range
LM4041-ADJ .......................................... 1.24V to 10V
+
Functional Diagram
LM4040, LM4041 Fixed Functional Diagram
LM4041 Adjustable
+
FB
VREF
Note 1. Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the
device is functional, but do not guarantee specific performance limits. For guaranteed specification and test conditions, see the
“Electrical
Characteristics”
. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when
the device is not operated under the listed test conditions.
Note 2. The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX (maximum junction temperature), θJA
(junction to ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any temperature is
PDMAX = (TJMAX – TA)/θJA or the number given in the Absolute Maximum Ratings, whichever is lower. For the LM4040 and LM4041,
TJMAX = 125°C, and the typical thermal resistance (θJA), when board mounted, is 326°C/W for the SOT-23 package.
Note 3. The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor
discharged directly into each pin.
LM4040/4041 Micrel
M9999-081604 4 August, 2004
LM4040-2.5 Electrical Characteristics (Note 4)
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25°C. The grades C and D designate initial Reverse
Breakdown Voltage tolerance of ±0.5% and ±1.0 respectively.
LM4040CIM3 LM4040DIM3
Symbol Parameter Conditions Typical Units
(Note 5) Limits Limits (Limit)
(Note 6) (Note 6)
VRReverse Breakdown Voltage IR = 100µA 2.500 V
Reverse Breakdown Voltage IR = 100µA±12 ±25 mV (max)
Tolerance (Note 7) ±29 ±49 mV (max)
IRMIN Minimum Operating Current 45 µA
60 65 µA (max)
65 70 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA ±20 ppm/°C
Voltage Temperature IR = 1mA ±15 ±100 ±150 ppm/°C (max)
Coefficient IR = 100µA±15 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.3 mV
Change with Operating 0.8 1.0 mV (max)
Current Change 1.0 1.2 mV (max)
1mA ≤ IR 15mA 2.5 mV
6.0 8.0 mV (max)
8.0 10.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.3 Ω
IAC = 0.1 IR0.9 1.1 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 35 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
Note 4. Specification for packaged product only.
Note 5. Typicals are at TJ = 25°C and represent most likely parametric norm.
Note 6. Limits are 100% production tested at 25°C. Limits over temperature are guaranteed through correlation using Statistical Quality Control (SQL)
methods.
Note 7. The boldface (over temperature limit for Reverse Breakdown Voltage Tolerance is defined as the room temperature Reverse Breakdown
Voltage Tolerance ±[(∆VR/∆T)(65°C)(VR)]. ∆VR/∆T is the VR temperature coefficient, 65°C is the temperature range from –40°C to the
reference point of 25°C, and VR is the reverse breakdown voltage. The total over temperature tolerance for the different grades follows:
C-grade: ±1.15% = ±0.5% ±100ppm/°C × 65°C
D-grade: ±1.98% = ±1.0% ±150ppm/°C × 65°C
Example: The C-grade LM4040-2.5 has an over temperature Reverse Breakdown Voltage tolerance of ±2.5 × 1.15% = ±29mV.
August, 2004 5 M9999-081604
LM4040/4041 Micrel
LM4040-4.1 Electrical Characteristics (Note 4)
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25°C. The grades C and D designate initial Reverse
Breakdown Voltage tolerance of ±0.5% and ± 1.0% respectively.
LM4040CIM3 LM4040DIM3
Symbol Parameter Conditions Typical Units
(Note 5) Limits Limits (Limits)
(Note 6) (Note 6)
VRReverse Breakdown Voltage IR = 100µA 4.096 V
Reverse Breakdown Voltage IR = 100µA±20 ±41 mV (max)
Tolerance (Note 7) ±47 ±81 mV (max)
IRMIN Minimum Operating Current 50 µA
68 73 µA (max)
73 78 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA ±30 ppm/°C
Voltage Temperature IR = 1mA ±20 ±100 ±150 ppm/°C (max)
Coefficient IR = 100µA±20 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.5 mV
Change with Operating 0.9 1.2 mV (max)
Current Change 1.2 1.5 mV (max)
1mA ≤ IR 15mA 3.0 mV
7.0 9.0 mV (max)
10.0 13.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.5 Ω
IAC = 0.1 IR1.0 1.3 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 80 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
Note 4. Specification for packaged product only.
Note 5. Typicals are at TJ = 25°C and represent most likely parametric norm.
Note 6. Limits are 100% production tested at 25°C. Limits over temperature are guaranteed through correlation using Statistical Quality Control (SQL)
methods.
Note 7. The boldface (over temperature limit for Reverse Breakdown Voltage Tolerance is defined as the room temperature Reverse Breakdown
Voltage Tolerance ±[(∆VR/∆T)(65°C)(VR)]. ∆VR/∆T is the VR temperature coefficient, 65°C is the temperature range from –40°C to the
reference point of 25°C, and VR is the reverse breakdown voltage. The total over temperature tolerance for the different grades follows:
C-grade: ±1.15% = ±0.5% ±100ppm/°C × 65°C
D-grade: ±1.98% = ±1.0% ±150ppm/°C × 65°C
Example: The C-grade LM4040-2.5 has an over temperature Reverse Breakdown Voltage tolerance of ±2.5 × 1.15% = ±29mV.
LM4040/4041 Micrel
M9999-081604 6 August, 2004
LM4040-5.0 Electrical Characteristics (Note 4)
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25°C. The grades C and D designate initial Reverse
Breakdown Voltage tolerance of ±0.5% and ± 1.0% respectively.
LM4040CIM3 LM4040DIM3
Symbol Parameter Conditions Typical Units
(Note 5) Limits Limits (Limits)
(Note 6) (Note 6)
VRReverse Breakdown Voltage IR = 100µA 5.000 V
Reverse Breakdown Voltage IR = 100µA±25 ±50 mV (max)
Tolerance (Note 7) ±58 ±99 mV (max)
IRMIN Minimum Operating Current 54 µA
74 79 µA (max)
80 85 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA ±30 ppm/°C
Voltage Temperature IR = 1mA ±20 ±100 ±150 ppm/°C (max)
Coefficient IR = 100µA±20 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.5 mV
Change with Operating 1.0 1.3 mV (max)
Current Change 1.4 1.8 mV (max)
1mA ≤ IR 15mA 3.5 mV
8.0 10.0 mV (max)
12.0 15.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.5 Ω
IAC = 0.1 IR1.1 1.5 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 80 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
Note 4. Specification for packaged product only.
Note 5. Typicals are at TJ = 25°C and represent most likely parametric norm.
Note 6. Limits are 100% production tested at 25°C. Limits over temperature are guaranteed through correlation using Statistical Quality Control (SQL)
methods.
Note 7. The boldface (over temperature limit for Reverse Breakdown Voltage Tolerance is defined as the room temperature Reverse Breakdown
Voltage Tolerance ±[(∆VR/∆T)(65°C)(VR)]. ∆VR/∆T is the VR temperature coefficient, 65°C is the temperature range from –40°C to the
reference point of 25°C, and VR is the reverse breakdown voltage. The total over temperature tolerance for the different grades follows:
C-grade: ±1.15% = ±0.5% ±100ppm/°C × 65°C
D-grade: ±1.98% = ±1.0% ±150ppm/°C × 65°C
Example: The C-grade LM4040-2.5 has an over temperature Reverse Breakdown Voltage tolerance of ±2.5 × 1.15% = ±29mV.
August, 2004 7 M9999-081604
LM4040/4041 Micrel
LM4040 Typical Characteristics
+0.5
+0.4
+0.3
+0.2
+0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
-40
-22ppm/°C
-51ppm/°C
IR = 150µA
12ppm/°C
TEMPERATURE (°C)
VR CHANGE (%)
Temperature Drift for Different
Average Temperature Coefficient
-200 20406080100
Output Impedance
vs. Frequency
IR = IRMIN + 100 µA
VR = 5V
2.5V
100 1k 10k 100k 1M
FREQUENCY (Hz)
CL
= 1µF
TANTALUM
XCL
1k
100
10
1
0.1
IMPEDANCE (Ω)
T
J
= 25 °C, ∆ I
R
= 0.1 I
R
CL = 0
Output Impedance
vs. Frequency
IR= 1mA
TJ = 25 °C, ∆IR = IR
CL= 0
CL= 1µF
TANTALUM
VR = 5V
2.5V
1k
100
10
1
0.1
100 1k 10k 100k 1M
FREQUENCY (Hz)
IMPEDANCE (Ω)
LM4040-5.0 R
S
= 30k
Start-up Characteristics
T
J
= 25°C
10
0
6
4
2
0
0 100 200 300 400
RESPONSE TIME (µs)
V
R
(V) V
IN
(V)
T
J
= 25°C
LM4040-2.5 RS = 30k
Start-up Characteristics
0 20 40 60 80
5
0
3
2
1
0
RESPONSE TIME (µs)
V
R
(V) V
IN
(V)
Test Circuit
V
IN
1Hz rate LM4040
R
S
V
R
10.0
5.0
1 10 100 1k 10k 100k
FREQUENCY (Hz)
2.0
1.0
0.5
0.2
IR = 200µA
TJ = 25°C
5V
2.5V
Noise Voltage
vs. Frequency
0.1
Noise (µV/ Hz )
√
¥
¥
¥
¥
REVERSE VOLTAGE (V)
C Suffix
D Suffix
Reverse Characteristics and
Minimum Operating Current
120
100
80
60
40
20
0
0 2 4 6 8 10
T
J
= 25°C
Typical
IRMIN
Guaranteed
2.5V
4.1V
5V
REVERSE CURRENT (µA)
LM4040/4041 Micrel
M9999-081604 8 August, 2004
LM4041-1.2 Electrical Characteristics (Note 4)
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25°C. The grades C and D designate initial Reverse
Breakdown Voltage tolerance of ±0.5% and ± 1.0%, respectively.
LM4041CIM3
Symbol Parameter Conditions Typical Units
(Note 5) Limits (Limit)
(Note 6)
VRReverse Breakdown Voltage IR = 100µA 1.225 V
Reverse Breakdown Voltage IR = 100µA±6 mV (max)
Tolerance (Note 7) ±14 mV (max)
IRMIN Minimum Operating Current 45 µA
60 µA (max)
65 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA ±20 ppm/°C
Voltage Temperature IR = 1mA ±15 ±100 ppm/°C (max)
Coefficient IR = 100µA±15 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.7 mV
Change with Operating 1.5 mV (max)
Current Change 2.0 mV (max)
1mA ≤ IR 15mA 4.0 mV
6.0 mV (max)
8.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.5 Ω
IAC = 0.1 IR1.5 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 20 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
Note 4. Specification for packaged product only.
Note 5. Typicals are at TJ = 25°C and represent most likely parametric norm.
Note 6. Limits are 100% production tested at 25°C. Limits over temperature are guaranteed through correlation using Statistical Quality Control (SQL)
methods.
Note 7. The boldface (over temperature limit for Reverse Breakdown Voltage Tolerance is defined as the room temperature Reverse Breakdown
Voltage Tolerance ±[(∆VR/∆T)(65°C)(VR)]. ∆VR/∆T is the VR temperature coefficient, 65°C is the temperature range from –40°C to the
reference point of 25°C, and VR is the reverse breakdown voltage. The total over temperature tolerance for the different grades follows:
C-grade: ±1.15% = ±0.5% ±100ppm/°C × 65°C
D-grade: ±1.98% = ±1.0% ±150ppm/°C × 65°C
Example: The C-grade LM4040-2.5 has an over temperature Reverse Breakdown Voltage tolerance of ±2.5 × 1.15% = ±29mV.
August, 2004 9 M9999-081604
LM4040/4041 Micrel
LM4041-1.2 Electrical Characteristics (Note 4)
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25°C. The grades C and D designate initial Reverse
Breakdown Voltage tolerance of ±0.5% and ± 1.0%, respectively.
LM4041DIM3
Typical Limits Units
Symbol Parameter Conditions (Note 5) (Note 6) (Limit)
VRReverse Breakdown Voltage IR = 100µA 1.225 V
Reverse Breakdown Voltage IR = 100µA±12 mV (max)
Tolerance (Note 7) ±24 mV (max)
IRMIN Minimum Operating Current 45 µA
65 µA (max)
70 µA (max)
∆VR/∆T Average Reverse Breakdown IR = 10mA ±20 ppm/°C
Voltage Temperature IR = 1mA ±15 ±150 ppm/°C (max)
Coefficient IR = 100µA±15 ppm/°C (max)
∆VR/∆IRReverse Breakdown Voltage IRMIN ≤ IR 1mA 0.7 mV
Change with Operating 2.0 mV (max)
Current Change 2.5 mV (max)
1mA ≤ IR 15mA 2.5 mV
8.0 mV (max)
10.0 mV (max)
ZRReverse Dynamic Impedance IR = 1mA, f = 120Hz 0.5 Ω
IAC = 0.1 IR2.0 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 20 µVRMS
∆VRReverse Breakdown Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
Note 4. Specification for packaged product only.
Note 5. Typicals are at TJ = 25°C and represent most likely parametric norm.
Note 6. Limits are 100% production tested at 25°C. Limits over temperature are guaranteed through correlation using Statistical Quality Control (SQL)
methods.
Note 7. The boldface (over temperature limit for Reverse Breakdown Voltage Tolerance is defined as the room temperature Reverse Breakdown
Voltage Tolerance ±[(∆VR/∆T)(65°C)(VR)]. ∆VR/∆T is the VR temperature coefficient, 65°C is the temperature range from –40°C to the
reference point of 25°C, and VR is the reverse breakdown voltage. The total over temperature tolerance for the different grades follows:
C-grade: ±1.15% = ±0.5% ±100ppm/°C × 65°C
D-grade: ±1.98% = ±1.0% ±150ppm/°C × 65°C
Example: The C-grade LM4040-2.5 has an over temperature Reverse Breakdown Voltage tolerance of ±2.5 × 1.15% = ±29mV.
LM4040/4041 Micrel
M9999-081604 10 August, 2004
LM4041-Adjustable Electrical Characteristics (Note 4)
Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TJ = 25°C unless otherwise specified (SOT-23, see Note 8),
IRMIN ≤ IR < 12mA, VREF ≤ VOUT ≤ 10V. The grades C and D designate initial Reverse Breakdown Voltage tolerance of ±0.5% and
±1%, respectively for VOUT = 5V.
LM4041CIM3 LM4041DIM3
Symbol Parameter Conditions Typical Units
(Note 5) Limits Limits (Limit)
(Note 6) (Note 6)
VREF Reference Breakdown Voltage IR = 100µA 1.233 V
VOUT = 5V
Reference Breakdown Voltage IR = 100µA±6.2 ±12 mV (max)
Tolerance (Note 9) ±14 ±24 mV (max)
IRMIN Minimum Operating Current 45 µA
60 65 µA (max)
65 70 µA (max)
∆VREF Reference Voltage IRMIN ≤ IR 1mA 0.7 mV
/∆IRChange with Operating SOT-23: 1.5 2.0 mV (max)
Current Change VOUT ≥ 1.6V 2.0 2.5 mV (max)
(Note 8)
1mA ≤ IR 15mA 2 mV
SOT-23: 4 6 mV (max)
VOUT ≥ 1.6V 68mV (max)
(Note 8)
∆VREF Reference Voltage Change IR = 1mA –1.55 mV/V
/∆VOwith Output Voltage Change –2.0 –2.5 mV/V (max)
–2.5 –3.0 mV/V (max)
IFB Feedback Current 60 nA
100 150 nA (max)
120 200 nA (max)
∆VREF Average Reference VOUT = 5V
/∆T Voltage Temperature IR = 10mA ±20 ppm/°C
Coefficient IR = 1mA ±15 ±100 ±150 ppm/°C (max)
(Note 9) IR = 100µA±15 ppm/°C (max)
ZOUT Dynamic Output Impedance IR = 1mA, f = 120Hz
IAC = 0.1 IR
VOUT = VREF 0.3 Ω
VOUT = 10V 2 Ω (max)
eNWideband Noise IR = 100µA
10Hz ≤ f ≤ 10kHz 20 µVRMS
∆VREF Reference Voltage t = 1000hrs
Long Term Stability T = 25°C ±0.1°C 120 ppm
IR = 100µA
Note 4. Specification for packaged product only.
Note 5. Typicals are at TJ = 25°C and represent most likely parametric norm.
Note 6. Limits are 100% production tested at 25°C. Limits over temperature are guaranteed through correlation using Statistical Quality Control (SQL)
methods.
Note 7. The boldface (over temperature limit for Reverse Breakdown Voltage Tolerance is defined as the room temperature Reverse Breakdown
Voltage Tolerance ±[(∆VR/∆T)(65°C)(VR)]. ∆VR/∆T is the VR temperature coefficient, 65°C is the temperature range from –40°C to the
reference point of 25°C, and VR is the reverse breakdown voltage. The total over temperature tolerance for the different grades follows:
C-grade: ±1.15% = ±0.5% ±100ppm/°C × 65°C
D-grade: ±1.98% = ±1.0% ±150ppm/°C × 65°C
Example: The C-grade LM4040-2.5 has an over temperature Reverse Breakdown Voltage tolerance of ±2.5 × 1.15% = ±29mV.
Note 8. When VOUT ≤ 1.6V, the LM4041-ADJ must operate at reduced IR. This is caused by the series resistance of the die attach between the die (–)
output and the package (–) output pin. See the Output Saturation curve in the
“Typical Performance Characteristics”
section.
Note 9. Reference voltage and temperature coefficient will change with output voltage. See
“Typical Performance Characteristics”
curves.
August, 2004 11 M9999-081604
LM4040/4041 Micrel
+0.5
+0.4
+0.3
+0.2
+0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
-40
-22ppm/°C
-51ppm/°C
IR = 150µA
LM4041-1.2
12ppm/°C
TEMPERATURE (°C)
VR CHANGE (%)
Temperature Drift for Different
Average Temperature Coefficient
-200 20406080100
CL= 1µF
TANTALUM
Output Impedence
vs. Frequency
1k
100
10
1
0.1100 1k 10k 100k 1M
FREQUENCY (Hz)
TJ = 25° C
∆IR = 0.1IR
LM4041-1.2 CL= 0
XC
IR
= 150µA
IR = 1mA
IMPEDANCE (Ω)
Voltage Impedance
1000
800
600
400
200
01 10 100 1k 10k 100k
FREQUENCY (Hz)
IR = 200µA
TJ = 25°C
LM4041-1.2
LM4041-ADJ: VOUT = VREF
√
NOISE (nV/ Hz )
Reverse Characteristics and
Minimum Operating Current
REVERSE VOLTAGE (V)
100
80
60
40
20
00 0.4 0.8 1.2 1.6 2.0
Typical
TJ = 25°C
LM4041-1.2
REVERSE CURRENT (µA)
10.0
5.0
1 10 100 1k 10k 100k
FREQUENCY (Hz)
2.0
1.0
0.5
0.2
IR = 200µA
TJ = 25°C
5V
2.5V
Noise Voltage
vs. Frequency
0.1
Noise (µV/ Hz )
√
R
S
30k
V
IN
1Hz rate LM4041-1.2 V
R
Test Circuit
LM4041 Typical Characteristics
LM4040/4041 Micrel
M9999-081604 12 August, 2004
LM4041 Typical Characteristics
LM4041-ADJ
85°C
25°C
-40°C
-40°C
85°C
Reference Voltage vs. Output
Voltage and Temperature
1.244
1.240
1.236
1.232
1.228
1.224
1.2200 2 4 6 8 10
OUTPUT VOLTAGE (V)
REFERENCE VOLTAGE (V)
Reference Voltage vs.
Temperature and Output Voltage
1.244
1.240
1.236
1.232
1.228
1.224
1.220
-40 -20 0 20 40 60 80 100
TEMPERATURE (°C)
LM4041-ADJ
VOUT = VREF
VOUT = 5V
VOUT = 10V
IR = 1mA
REFERENCE VOLTAGE (V)
TJ = 85°C
LM4041-ADJ
TJ = 25°C, -40°C
Feedback Current vs.
Output Voltage and Temperature
0 2 4 6 8 10
OUTPUT VOLTAGE (V)
100
80
60
40
20
0
FEEDBACK (nA)
Output Saturation
0 2 4 6 8 10 12
OUTPUT CURRENT (mA)
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
LM4041-ADJ
VADJ = VREF + 5µV
-40°C
85°C
25°C
OUTPUT SATURATION (V)
FB STEPS (V)
0 2 4 6 8 10
T
J
= 25°C
LM4041-ADJ
0 2 4 6 8
100
80
60
40
20
0
Reverse Characteristics
†
OUTPUT VOLTAGE (V)
REVERSE CURRENT (µA)
LM4041-ADJ
TJ = -40°C
25°C
85°C
0 10 20 30 40
-40°C
OUTPUT
INPUT -40°C
Large Signal Response ‡
10
8
6
4
2
0
RESPONSE TIME (µs)
VOLTAGE (V)
* Output Impedance vs. Freq.
Test Circuit
‡ Large Signal Response
Test Circuit
† Reverse Characteristics
Test Circuit
FB
2V / step
V
OU
T
I
R
( + )
( – )
LM4041-ADJ
V
VOUT
LM4041 - ADJ
( + )
FB
( - )
100k
INPUT
+ 15V
5.1k
–
+
CL
120k
FB
IR
LM4041-ADJ
T
J
= 25 °C
I
R
= 1mA
∆I
R
= 0.1I
R
CL = 0
CL=1µF
XC
V
OUT
= 10V
5V
2.5V
1.23V
Output Impedence
vs. Frequency *
1K
100
10
1
0100 1k 10k 100k 1M
FREQUENCY (Hz)
IMPEDANCE (Ω)
C
L
= 0
C
L
=1µF
X
C
5V
2.5V
1.23V
FREQUENCY (Hz)
100 1k 10k 100k 1M
1K
100
10
1
0
Output Impedence
vs. Frequency *
IMPEDANCE (Ω)
V
OUT
= 10V
LM4041-ADJ
T
J
= 25 °C
I
R
= 150µA
∆I
R
= 0.1 I
R
*Output impedance measurement..
†Reverse characteristics measurement.
‡Large signal response measurement.
August, 2004 13 M9999-081604
LM4040/4041 Micrel
Applications Information
The stable operation of the LM4040 and LM4041 references
requires an external capacitor greater than 10nF connected
between the (+) and (–) pins. Bypass capacitors with values
between 100pF and 10nF have been found to cause the
devices to exhibit instabilities.
Schottky Diode
LM4040-x.x and LM4041-1.2 in the SOT-23 package have a
parasitic Schottky diode between pin 2 (–) and pin 3 (die
attach interface connect). Pin 3 of the SOT-23 package must
float or be connected to pin 2. LM4041-ADJs use pin 3 as the
(–) output.
Conventional Shunt Regulator
In a conventional shunt regulator application (see Figure 1),
an external series resistor (RS) is connected between the
supply voltage and the LM4040-x.x or LM4041-1.2 reference.
RS determines the current that flows through the load (IL) and
the reference (IQ). Since load current and supply voltage may
vary, RS should be small enough to supply at least the
minimum acceptable IQ to the reference even when the
supply voltage is at its minimum and the load current is at its
maximum value. When the supply voltage is at its maximum
and IL is at its minimum, RS should be large enough so that
the current flowing through the LM4040-x.x is less than
15mA, and the current flowing through the LM4041-1.2 or
LM4041-ADJ is less than 12mA.
RS is determined by the supply voltage (VS), the load and
operating current, (IL and IQ), and the reference’s reverse
breakdown voltage (VR):
Rs = (Vs – VR) / (IL + IQ)
Adjustable Regulator
The LM4041-ADJ’s output voltage can be adjusted to any
value in the range of 1.24V through 10V. It is a function of the
internal reference voltage (VREF) and the ratio of the external
feedback resistors as shown in Figure 2. The output is found
using the equation:
(1) VO = VREF [ (R2/R1) + 1 ]
where VO is the desired output voltage. The actual value of
the internal VREF is a function of VO. The “corrected” VREF is
determined by:
(2) VREF´ = VO (∆VREF / ∆VO) + VY
where VO is the desired output voltage. ∆VREF / ∆VO is found
in the
“Electrical Characteristics”
and is typically –1.3mV/V
and VY is equal to 1.233V. Replace the value of VREF in
equation (1) with the value VREF found using equation (2).
Note that actual output voltage can deviate from that pre-
dicted using the typical ∆VREF / ∆VO in equation (2); for C-
grade parts, the worst-case ∆VREF / ∆VO is –2.5mV/V and
VY = 1.248V.
The following example shows the difference in output voltage
resulting from the typical and worst case values of
∆VREF / ∆VO.
Let VO = +9V. Using the typical values of ∆VREF /∆VO , VREF
is 1.223V. Choosing a value of R1 = 10kΩ, R2 = 63.272kΩ.
Using the worst case ∆VREF / ∆VO for the C-grade and D-
grade parts, the output voltage is actually 8.965V and 8.946V
respectively. This results in possible errors as large as 0.39%
for the C-grade parts and 0.59% for the D-grade parts. Once
again, resistor values found using the typical value of
∆VREF / ∆VO will work in most cases, requiring no further
adjustment.
Figure 4. Voltage Level Detector
R1
120
k
R2
1M
FB
+
–
LM4041-ADJ
D1
λ
< –12V
LED ON
R3
200
–5V
D1 λ
LM4041-
ADJ
R1
120k
R2
1M
FB
–
+
R3
330
> –12V
LED ON
–5V
Figure 3. Voltage Level Detector
Typical Application Circuits
LM4040/4041 Micrel
M9999-081604 14 August, 2004
Figure 8. Bidirectional Adjustable Clamp
±2.4 to ±6V
V
IN
R1I
LM4041-ADJ
D2
1N457
R3
1M
R2
330k
V
OUT
LM4041-ADJ
FB
+
–
FB –
+
D1
1N457 R4
330k
V
IN
R1
R2
390k
R3
500k
FB
+
–
LM4041-ADJ
D1
1N457
R4
390k
D2
1N457
LM4041-ADJ
FB
+
–
I
V
OUT
Figure 7. Bidirectional Adjustable Clamp
±18V to ±2.4V
0 to 20mA
R1
390Ω
± 2%
1N4002
D2
LM4041-ADJ
+
–
FB
λ
D1* 1
2
3
6
5
4
4N28
N.C.
I
THRESHOLD
=
+
= 3.2mA
1.24V
R1 5µA
4N28 GAIN
N.C.
R2
470k
CMOS
+ 5V
* D1 can be any LED, VF = 1.5V to 2.2V at 3mA. D1 may act as an indicator.
D1 will be on if ITHRESHOLD falls below the threshold current, except with I = O.
Figure 9. Floating Current Detector
D1
1N457 R3
510k
LM4041-ADJ
D2
1N457
V
OUT
R2
510k
V
IN
R1
I
+FB FB
LM4041-ADJ +
–
–
Figure 6. Bidirectional Clamp
±2.4V
Figure 5. Fast Positive Clamp
2.4V + ∆VD1
VIN
VOUT
D1
1N914
D2
1N914
R3
240k
R4
240k
R1
I
R2
50µA
LM4041-ADJ FB
+
–
August, 2004 15 M9999-081604
LM4040/4041 Micrel
+15V
R1
2N2905
2N
3964
R2
120k
LM4041-ADJ FB
+
–
1.24V
R1
I
OUT
=
1µA < I
OUT
= 100mA
+5V
R3
100k
CMOS
R4
10M
1
2
3
6
5
4
4N28
N.C.
R2
22k
LM4041-ADJ
+
–
R1
332Ω
±1% FB
1N914
2N2222
D1* λ
ITHRESHOLD = = 3.7mA ± 2%
1.24V
R1
D2
1N4002
0 to 20 mA
Figure 10. Current Source
* D1 can be any LED, VF = 1.5V to 2.2V at 3mA. D1 may act as an indicator.
D1 will be on if ITHRESHOLD falls below the threshold current, except with I = O.
Figure 11. Precision Floating Current Detector
LM4040/4041 Micrel
M9999-081604 16 August, 2004
Package Information
0.15 (0.006)
0.076 (0.0030)
0.41 (0.016)
0.13 (0.005)
3.05 (0.120)
2.67 (0.105) 8°
0°
0.445 (0.0175) TYP 3 PLACES
2.50 (0.098)
2.10 (0.083)
1.40 (0.055)
1.19 (0.047)
0.10 (0.004)
0.013 (0.0005)
1.15 (0.045)
0.76 (0.030)
DIMENSIONS:
MM (INCH)
2.36 (0.093)
2.28 (0.090)
C
L
C
L
SOT-23 (M3)
MICREL, INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 474-1000 WEB http://www.micrel.com
The information furnished by Micrel in this datasheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use.
Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into
the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s
use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser’s own risk and Purchaser agrees to fully indemnify
Micrel for any damages resulting from such use or sale.
© 2004 Micrel, Incorporated.
