NJRC NJM2825F Precision micropower shunt voltage reference Datasheet

NJM2825
Precision Micropower Shunt Voltage Reference
■GENERAL DESCRIPTION
■PACKAGE OUTLINE
NJM2825 is a precision and low quiescent current shunt voltage
reference.
Reference voltage form bandgap circuit has guaranteed the high
accuracy of the ±0.5% with trimming. In addition the temperature drift of
10ppm/°C typ. was actualized by the temperature compensating circuit.
The reference voltage circuit operates by consumed low quiescent current
of the 0.7µA for low power technology.
The Output capacitor is unnecessary by the phase compensating circuit
which is built in. Tolerates capacitive loads, it is easy to use for application.
It is suitable for data converters, instrumentation, and other applications
where precision reference is required.
■FEATURES
● Precision Reference Voltage
1,200mV±0.5%
● Low temperature coefficient
10ppm/°C typ.
● Low Quiescent Current
0.7µA max.
● No Output Capacitor Required
● Tolerates Capacitive Loads
● Bipolar Technology
● Package Outline
NJM2825F : SOT-23-5 (MTP5)
■BLOCK DIAGRAM
NJM2825F
■PRODUCT VARIATION
NJM2825
±0.5%, IMIN=0.7µA
NJM2823
±0.4%, IMIN=60µA
■PIN CONFIGURATION
CATHODE
5 CATHODE
NC 1
ANODE 2
VREF
NC 3
FB
4 FB
NJM2825F
ANODE
Ver.2009-03-05
-1-
NJM2825
■ABSOLUTE MAXIMUM RATINGS (Ta=25°C)
PARAMETER
SYMBOL
Cathode Voltage
VKA
Cathode Current
IK
Cathode-Anode Reverse Current
-IK
Power Dissipation
PD
Operating Temperature Range
TOPR
Storage Temperature Range
TSTG
MAXIMUM RATINGS
14
20
10
200
-40 ∼ +85
-40 ∼ +125
■RECOMMENDED OPERATING CONDITIONS (Ta=25°C)
PARAMETER
SYMBOL MIN.
TYP.
Cathode Voltage
Cathode Current
VKA
IK
VREF
0.7µ
MAX.
UNIT
13
12
V
mA
–
–
■ELECTRICAL CHARACTERISTICS (IK=0.8µA,Ta=25°C)
PARAMETER
SYMBOL
TEST CONDITION
Reference Voltage
Load Regulation
Reference Voltage
Change vs. Cathode
Voltage Change
Minimum Operating
Current
Feedback Current
Dynamic Impedance
VREF
∆VREF/
∆IK
∆VREF/
∆VKA
IMIN
IFB
ZKA
MIN.
TYP.
MAX.
UNIT
VFB=VA
VFB=VA, IMIN≤ IK≤ 200µA
VFB=VA, 200µA ≤ IK≤ 2mA
VFB=VA, 2mA≤ IK≤ 12mA
(*1)
(*1)
(*1)
(*1)
1194.0
–
–
–
1200.0
0.2
0.7
3.4
1206.0
0.7
2
10
mV
mV
mV
mV
VREF≤ VKA≤ 13V, IK=2µA
R1=120kΩ, R2=val (Note 1)
(*2)
–
-1
-2
mV/V
VREF≤ VKA≤ 5V
5V≤ VKA≤ 13V
R1=∞, R2=120kΩ
VFB=VA, IK=0.7µA∼12mA
(*2)
(*2)
(*2)
(*1)
–
–
–
–
0.3
1
0.3
0.4
0.7
2
1
1.1
µA
µA
nA
Ω
MIN.
TYP.
MAX.
UNIT
■TEMPERATURE CHARACTERISTICS (IK=0.8µA, Ta= -40°C ∼ 85°C)
PARAMETER
SYMBOL
TEST CONDITION
Reference Voltage
Change
(Note 2)
Reference Voltage
(Note 2)
Feedback Current
Change
UNIT
V
mA
mA
mW
°C
°C
∆VREF_T
VFB=VA
(*1)
–
0.8
10
2.3
30
mV
ppm/°C
VREF_T
VFB=VA
(*1)
1191.7
1200.0
1208.3
mV
R1=∞, R2=120kΩ
(*2)
–
0.4
–
nA
IFB_T
Note 1: VREF···Reference voltage includes error.
Note 2: Reference Voltage Change is defined as
∆VREF_T [mV] = ± < Reference Voltage Change [ppm/°C] > × <-40°C ∼ 25°C> × VREF
The maximum value of “Reference Voltage Change” is determined based on sampling evaluation from the 5 initial
production lots, and thus not tested in the production test. Therefore, these values are for the reference design
purpose only.
(*1): Test Circuit (Fig.1)
(*2): Test Circuit (Fig.2)
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Ver.2009-03-05
NJM2825
■TEST CIRCUIT
Input
VKA
Input
VKA
IK
VREF
IK
CATHODE
VREF
R1
FB
CATHODE
FB
R2
ANODE
IFB
Fig.1 VKA=VREF to test circuit
ANODE
Fig.2 VKA>VREF to test circuit
R2 

VKA = VREF1 +
 + IFB × R2
R1 

VFB=VA
■TYPICAL CHARACTERISTICS
Reference Voltage vs. Temperature
(I =0.8µA, V =V )
K
FB
15
A
Reference Voltage Change
∆VREF (mV)
Reference Voltage VREF [mV]
1206
1204
Reference Voltage vs Cathode Current
(VFB=VA )
Ta=-40 oC
12
1202
1200
1198
1196
1194
-50
9
6
o
Ta=25 C
3
o
Ta=75 C
0
0.0001 0.001 0.01 0.1
1
10
Cathode Current Ik (mA)
-25
0
25 50 75 100 125
Ambient Temperature Ta (oC)
Reference Voltage vs. Cathode Voltage
Reference Voltage vs. Cathode Current
o
A
(mV)
FB
1400
1000
800
600
400
(R1=120kΩ, R2=val, IK=2µA, Ta=25 C)
1202
1200
REF
1200
Reference Voltage V
Reference Voltage VREF (mV)
o
(V =V , Ta=25 C)
100
1198
1196
1194
1192
1190
1188
0
Ver.2009-03-05
0.2
0.4
0.6
0.8
Cathode Current Ik (µA)
1
0
5
10
Cathode Voltage VK (V)
15
-3-
NJM2825
■TYPICAL CHARACTERISTICS
Dynamic Impedance vs. Frequency
(V =V , Ta=25 C)
10
FB
IK=0.8µA
Cout=0 µF
1
2
A
IK=10µA
Cout=0 µF
0.1
0.01
IK=0.8µA
Cout=0.047 µF
0.001
0.0001
0.01
IK=10µA
Cout=0.1 µF
0.1
1
10
100
Frequency f (kHz)
1000
Feedback Current IFB (nA)
Dynamic Impedance |ZKA| (Ω)
o
Feedback Current vs. Temperature
(R1=Open, R2=120kΩ, IK=0.8µA)
1.5
1
0.5
0
-50
-25
0
25 50 75 100 125
o
Ambient Temperature Ta ( C)
Sefty Operating Boundary Condition
o
(V =V , Ta=25 C)
FB
Cathode Current IK (µA)
1
A
Ceramic Capacitor
0.8
0.6
Stable Operation Region
0.4
Note) Oscillation might occur while operating within the range
of safety curve.
So that, it is necessary to make ample margins by
taking considerations of fluctuation of the device.
0.2
Unstable Operation Region
0
0.001
0.01
0.1
1
Output Capacitance Co (µF)
10
Power Dissipation vs. Temperature
(MTP5=Itself, Tj= ∼125oC)
Power Dissipation PD (mW)
250
200
150
100
50
0
0
-4-
25
50
75
100
o
Ambient Temperature Ta ( C)
Ver.2009-03-05
NJM2825
■Application Information
The NJM2825 creates a highly accurate reference voltage, enabling a low power consumption application circuit to be
configured.
In the basic application (Fig.1) of the shunt regulator, a voltage drop is created by resistor Rs connected between the
input voltage and the NJM2825, and the output voltage (cathode – anode voltage = VKA) is controlled to a constant
value. The voltage drop due to Rs is determined by the total of the output current and the cathode current.
The feedback to the output voltage is controlled by the FB terminal, and the cathode current changes so that the set
voltage is obtained.
VIN
As a result, Rs must conform to the following conditions.
*Minimum cathode current = 0.7 uA min
Conditions under which the input voltage is a minimum
and the output current is a maximum.
R1
RS
VOUT=VKA
IK
VREF
CO
*Maximum cathode current = 12 mA max
Conditions under which the input voltage is a maximum
and the output current is a minimum.
R2
IFB
The value of resistor Rs is obtained by means of the following formula.
RS =
Fig.1 basic application
VIN − VOUT
[Ω]
IK + IOUT
The output voltage can be set using any desired value between VREF and 13 V.
The output voltage is set according to the ratio between the values of the two external resistors, however an error
occurs depending upon the feedback current. The error can be minimized by combining two external resistors with low
resistance values. The formula for calculating the output voltage setting is shown below.
 R2 
VOUT = 
+ 1 × VREF + IFB × R2
 R1 
As shown in the “reference voltage versus cathode voltage”
characteristics example, the reference voltage value has
negative characteristics. The reference voltage is corrected by
using ∆VREF/∆VKA stipulated by the electrical characteristics.
 ∆V
∆VREF =  REF
 ∆VKA

 × VOUT

VKA (V)
1.20
1.50
1.80
2.50
3.30
5.00
R1 (kΩ)
Open
120
120
120
120
120
R2 (kΩ)
Short
30.6
60.8
131
212
382
Table.1 Examples of output voltage settings at the standard
Table 1 shows an example of combining constants in the case where R1 is assumed to be 120 kΩ.
The error in the output voltage also varies with the accuracy of the resistors. In order to realize a highly accurate
application, the relative accuracy can be improved by either using accurate resistors or combining integrated resistors.
The NJM2825 contains an optimized phase compensation circuit. Consequently, in the basic application a stable
reference voltage is generated without the use of an output capacitor. As is indicated in the “dynamic impedance
versus frequency” characteristics, the impedance increases in proportion to the frequency. If necessary, connect an
output capacitor to reduce the high frequency impedance. You can connect a ceramic capacitor to obtain high stability,
but in this case be sure to use the NJM2825 in the stable operation region while referring to the “stable operation
boundary conditions” characteristics example.
Ver.2009-03-05
-5-
NJM2825
MEMO
[CAUTION]
The specifications on this databook are only
given for information , without any guarantee
as regards either mistakes or omissions. The
application circuits in this databook are
described only to show representative usages
of the product and not intended for the
guarantee or permission of any right including
the industrial rights.
-6-
Ver.2009-03-05
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