REF03 Analog Devices, Inc., REF03 Datasheet - Page 8

• Manufacturer Part Number: REF03
• Description: 2.5v Precision Voltage Reference
• Manufacturer: Analog Devices, Inc.

REF03
BOOST TRANSISTOR PROVIDES HIGH
OUTPUT CURRENT
When applications require more than 10 mA current delivery,
an external boost transistor may be added to the REF03 to pass
the required current without dissipating excessive power within
the IC. The maximum current output to the system is bounded
only by the capabilities of the boost transistor. Figure 19 shows
this technique, with and without current limiting.
Current limiting may be used to prevent damage to the boost
transistor. Figure 19A is an example of no current limit, while
Figure 19B shows the limit that occurs when the voltage dropped
across R2 exceeds one V
to the variations of the forward drop of the diodes and the
PNP’s V
temperature.
REF03
A. NO CURRENT LIMIT
GND
V
IN
2
V
4
65Ω
BE
OUT
with temperature, and also decreases with increasing
V+
6
2.49kΩ
2N2905
Figure 19. Output Current Boost
–2.5V
BE
(0.6 V). The current limit is sensitive
B. CURRENT LIMITING
REF03
1N4148
GND
V
V–
IN
2
V
4
OUT
R1
40Ω
6
2.49kΩ
2N2905
R2
10Ω
–2.5V
0mA TO 100mA
Rev. G | Page 8 of 12
CMOS DAC REFERENCE
The REF03 makes an excellent reference for use with CMOS
and bipolar DACs. Figure 20 shows the REF03 connected to
the AD7393, a 12-bit CMOS DAC. An
mode input range that extends to its positive rail can be a good
combination with only 50 μA of maximum current consumption.
REF03
GND
+5V
V
IN
2
V
4
OUT
6
V
DD
Figure 20. CMOS DAC Reference
AD7393
V
GND
REF
470kΩ
V
OUT
AD8603
470kΩ
AD8603
–2.5V
with a common
2.5V TO –2.5V
V
OUT