5962-8686103XA Analog Devices Inc, 5962-8686103XA Datasheet - Page 5

• Manufacturer Part Number: 5962-8686103XA
• Description: IC VOLT REF 2.5V PREC TO-52-3
• Manufacturer: Analog Devices Inc

Specifications of 5962-8686103XA

• Reference Type: Series
• Voltage - Output: 2.5V
• Tolerance: ±4%
• Voltage - Input: 4.5 ~ 40 V
• Number Of Channels: 1
• Current - Quiescent: 2mA
• Current - Output: 10mA
• Mounting Type: Through Hole
• Package / Case: TO-52-3, Metal Can
• Operating Temperature: -
• Temperature Coefficient: -
• Current - Cathode: -
• Other names: Q2504744

THEORY OF OPERATION
The AD580 family (AD580, AD581, AD584, AD589) uses the
bandgap concept to produce a stable, low temperature coef-
ficient voltage reference suitable for high accuracy data acqui-
sition components and systems. The device makes use of the
underlying physical nature of a silicon transistor base-emitter
voltage in the forward-biased operating region. All such tran-
sistors have approximately a –2 mV/°C temperature coefficient,
unsuitable for use directly as a low TC reference. Extrapolation
of the temperature characteristic of any one of these devices to
absolute zero (with an emitter current propor-tional to the
absolute temperature), however, reveals that it will go to a V
1.205 V at 0 K, as shown in Figure 3. Thus, if a voltage could be
developed with an opposing temperature coefficient to sum
with V
operation from a single, low voltage supply would be possible.
The AD580 circuit provides such a compensating voltage, V1 in
Figure 4, by driving two transistors at different current densities
and amplifying the resulting V
has a positive TC). The sum, V
up to 2.5 V to provide a usable reference-voltage output. Figure
5 shows the schematic diagram of the AD580.
The AD580 operates as a 3-terminal reference, meaning that no
additional components are required for biasing or current
setting. The connection diagram, Figure 6, is quite simple.
Figure 3. Extrapolated Variation of Base-Emitter Voltage with Temperature
(I
E
αT), and Required Compensation, Shown for Two Different Devices
1.205
BE
1.5
1.0
0.5
–273°C
0
to total 1.205 V, a 0 TC reference would result and
0K
V
FOR TWO TYPICAL
DEVICES (I
BE
–200°C
VS. TEMPERATURE
73K
E
α
T)
TEMPERATURE
BE
Z
, is then buffered and amplified
–100°C
CONSTANT SUM = 1.205V
173K
difference (∆V
FOR BOTH
DEVICES
REQUIRED
COMPENSATION
VOLTAGE–
SAME DEVICES
273K
0°C
BE
—which now
100°C
373K
BE
Rev. B | Page 5 of 8
of
VOLTAGE VARIATION VERSUS TEMPERATURE
Some confusion exists in the area of defining and specifying
reference voltage error over temperature. Historically, references
are characterized using a maximum deviation per degree
Centigrade; i.e., 10 ppm/°C. However, because of the
inconsistent nonlinearities in Zener references (butterfly or S
type characteristics), most manufacturers use a maximum limit
error band approach to characterize their references. This
technique measures the output voltage at 3 to 5 different
temperatures and guarantees that the output voltage deviation
will fall within the guaranteed error band at these discrete
temperatures. This approach, of course, makes no mention or
guarantee of performance at any other temperature within the
operating temperature range of the device.
COM
2I
COM
+V
∆
1
V
= I
IN
BE
1
Q8
Q2
8A
+ I
Figure 4. Basic Bandgap-Reference Regulator Circuit
Q10
2
Q2
8A
R8
R2
I
2
R8
R2
R1
≅
R1
Q1
I
A
R3
1
4.5
Figure 6. Connection Diagram
Figure 5. Schematic Diagram
R7
Q11
Q9
AD580
V
+E
R7
≤
1
V
Q1
A
BE
= 2
V
Q3
IN
(Q1)
R6
R
R
≤
1
2
30V
Q12
∆
Q14
V
C1
+E
BE
R4
R5
Q15
R12
–E
E
OUT
V
V
Q13
OUT
Z
R11
LOAD
R13
= V
= V
= V
= 1.205V
= V
Q5
BE
BE
BE
–E
Q4
Z
+ V
+ 2
+ 2
Q6
R10
1 +
1
R
R
R
R
R
R
1
2
1
2
4
5
∆
Q7
kT
q
V
R9
R4
R5
= 2.5V
BE
ln
J
J
AD580
1
2
2.5V
OUT