ADR280ART-R2 Analog Devices Inc, ADR280ART-R2 Datasheet - Page 8

• Manufacturer Part Number: ADR280ART-R2
• Description: IC REF VOLT HI PSRR 1.2V SOT-23
• Manufacturer: Analog Devices Inc

Specifications of ADR280ART-R2

• Rohs Status: RoHS non-compliant
• Design Resources: 4 mA-to-20 mA Loop-Powered Temperature Monitor Using ADuC7060/1 (CN0145)
• Reference Type: Series
• Voltage - Output: 1.2V
• Tolerance: ±0.4%
• Temperature Coefficient: 40ppm/°C
• Voltage - Input: 2.4 ~ 5.5 V
• Number Of Channels: 1
• Current - Quiescent: 16µA
• Current - Output: 100µA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-3, TO-236-3, Micro3™, SSD3, SST3
• Current - Cathode: -
• Other names: ADR280ART-R2TR

ADR280
APPLICATIONS INFORMATION
The ADR280 should be decoupled with a 0.1 μF ceramic
capacitor at the output for optimum stability. It is also good
practice to include 0.1 μF ceramic capacitors at the IC supply
pin. These capacitors should be mounted close to their
respective pins (see Figure 12).
The low supply voltage input pin V− can be elevated above
ground; a 1.2 V differential voltage can therefore be established
above V− (see Figure 13).
The ADR280 provides the core 1.2 V band gap voltage and is
able to drive a maximum load of only 100 μA. Users can simply
buffer the output for high current or sink/source current applica-
tions, such as ADC or LCD driver references (see Figure 14).
Users can also tailor any specific need for voltage and dynamics
with an external op amp and discrete components (see Figure 14
and Figure 15). Depending on the specific op amp and PCB
layout, it may be necessary to add a compensation capacitor, C2,
to prevent gain peaking and oscillation. The exact value of C2
needed requires some trial and error but usually falls in the
range of a few picofarads.
V
OUT
5V
0.1µF
0.1µF
U2
0.1µF
0.1µF
1.2V + V–
Figure 12. Basic Configuration
Figure 13. Floating References
Figure 14. Buffered Output
0.1µF
V+
V
OUT
V+
V
ADR280
OUT
ADR280
0.1µF
U2 = AD8541, SC70
U1
V–
V+
V
V–
OUT
ADR280
AD8601, SOT-23-5
V–
2.5V
Rev. C | Page 8 of 12
LOW COST, LOW POWER CURRENT SOURCE
Because of its low power characteristics, the ADR280 can be
converted to a current source with just a setting resistor. In
addition to the ADR280 current capability, the supply voltage
and the load limit the maximum current. The circuit in Figure 16
produces 100 μA with 2 V compliance at a 5 V supply. The load
current is the sum of I
load; a R
Precision Low Power Current Source
By adding a buffer to redirect the I
can be precisely set by R
120kΩ ± 0.1%
60kΩ ± 0.1%
1.8V
V
R2
R1
SET
O
of 13.6 kΩ yields 100 μA of load current.
R
Figure 17. Precision Low Power Current Source
12kΩ
R
1.2V
2.2pF
1kΩ
SET
1kΩ
SET
5V
RL
RL
C2
+
–
Figure 16. Low Cost Current Source
13.6kΩ
U2
Figure 15. 1.8 V Reference
0.1µF
5V
SET
AD8541
C1
I
100µA
I
L
5V
I
100µA
SET
SET
V+
V–
L
and I
+
–
with the equation I
I
L
0.1µF
AD8541
–
+
= 1.2V/R
U1
U1
GND
C2
V+
V–
V+
V
0.1µF
V+
V
I
L
OUT
OUT
= I
ADR280
5V
ADR280
C1
. I
5V
U2
GND
1.2V
SET
I
SET
GND
GND
+ I
in Figure 17, a current
increases slightly with
GND
V–
V–
U1
V+
V
OUT
ADR280
L
= 1.2 V/R
V–
SET
.