Datasheet

REF1112
5
SBOS283C
www.ti.com
APPLICATIONS INFORMATION
The REF1112 is a two-terminal bandgap reference diode
designed for high accuracy with outstanding temperature
characteristics at low operating currents. Precision thin-film
resistors result in 0.2% initial voltage accuracy and 50ppm/
°C
maximum temperature drift. The REF1112 is specified from
–40
°C to +85°C, with operation from –40°C to +125°C, and is
offered in a SOT23-3 package.
Typical connections for the REF1112 are shown in Figure 1.
A minimum 1µA bias current is required to maintain a stable
output voltage and can be provided with a resistor con-
nected to the supply voltage. I
BIAS
depends on the values
selected for R
BIAS
and V
S
, and will vary as a sum of the
minimum operating current and the load current. To main-
tain stable operation, the value of R
BIAS
must be low
enough to maintain the minimum operating current at the
minimum and maximum load and supply voltage levels.
FIGURE 1. Typical Connections.
A 0.1µF load capacitor is recommended to maintain stabil-
ity under varying load conditions. A minimum 0.01µF load
capacitor is required for stable operation. Start-up time for
the REF1112 will be affected, depending on the value of
load capacitance and the bias currents being used. A 1µF
power-supply bypass capacitor is recommended to mini-
mize supply noise within the circuit.
The REF1112 shunt voltage reference provides a versatile
function for low power and space-conservative applications.
The REF1112 can be configured with an additional diode
and NPN transistor to provide a temperature compensated
current reference as shown in Figure 2. The REF112 can be
scaled to provide extremely low power reference voltages.
Figure 3 shows the REF1112 used as a 1V out, 3µA voltage
reference, and in Figure 4 as a 2.5V reference on 1µA.
FIGURE 2. REF1112 Provides a Stable Current Source.
FIGURE 3. MicroPOWER 3µA 1V Voltage Reference.
FIGURE 4. 2.5V Reference on 1µA.
I
BIAS
= I
REF
+ I
LOAD
V
S
V
REF
R
BIAS
I
LOAD
I
BIAS
=
V
S
− V
REF
R
BIAS
0.1µF
I
REF
1µF
V
S
I
SET
0.1µF
R
SET
10kΩ
I
SET
=
V
REF
R
SET
0.1µF
3V
3V
V
REF
V
OUT
= 1V
795kΩ
250kΩ
1MΩ
REF1112
TLV2401
0.1µF
3V
R
LOAD
V
O
U
T
= 2.5V
0.1µF
R
SET