x60008b-50 Intersil Corporation, x60008b-50 Datasheet - Page 10

• Manufacturer Part Number: x60008b-50
• Description: Precision 5.0v Fga Voltage Reference
• Manufacturer: Intersil Corporation

0.1µF capacitor on the output, but noise in the 1Hz to
100Hz band increases due to instability of the very low
power amplifier with a 0.1µF capacitance load. For
load capacitances above .001µF the noise reduction
network shown in fig. 3 is recommended. This network
reduces noise sig-nificantly over the full bandwidth. As
shown in fig. 2, noise is reduced to less than 40µVp-p
from 1Hz to 1MHz using this network with a .01µF
capacitor and a 2k: resistor in series with a 10µF
capacitor.
Figure 2.
Figure 3.
Turn-On Time
The X60008 devices have ultra-low supply current and
thus the time to bias up internal circuitry to final values
will be longer than with higher power references. Nor-
mal turn-on time is typically 7ms. This is shown in the
graph, Figure 4. Since devices can vary in supply cur-
rent down to 300nA, turn-on time can last up to about
12ms. Care should be taken in system design to
include this delay before measurements or conver-
sions are started.
V
IN
= 6.5V
250
200
150
100
300
400
350
50
.1µF
0
1
10µF
X60008-50 NOISE REDUCTION
10
CL = 0
CL = .001µF
CL = .1µF
CL = .01µF & 10µF + 2k:
X60008-50
100
GND
V
10
IN
V
O
1000
.01µF
10000
100000
2K:
10µF
X60008B-50
Figure 4.
Temperature Coefficient
The limits stated for temperature coefficient (tempco)
are governed by the method of measurement. The
overwhelming standard for specifying the temperature
drift of a reference is to measure the reference voltage
at two temperatures, take the total variation, (V
measurement (T
the nominal reference voltage (at T = 25°C) and multi-
plied by 10
for temperature coefficient which allows comparison of
devices but can mislead a designer concerned about
specific ranges of temperature (i.e., 35°C to 65°C for a
power supply design). The designer may infer the
tempco to be a well-behaved flat line slope, similar to
that shown in Figure 5. The slope of the Vout vs. tem-
perature curve at points in-between the extremes can
actually be much higher than the tempco stated in the
specifications due to multiple inflections in the temper-
ature drift curve. Most notably, bandgap devices may
have some type of “s-curve” which will have slopes
that exceed the average specified tempco by 2x or 3x.
V
LOW
), and divide by the temperature extremes of
7
6
5
4
3
2
1
0
-1
6
to yield ppm/° C. This is the “Box” method
1
X60008-50 TURN-ON TIME (25°C)
I
IN
HIGH
= 730nA
3
- T
5
TIME (mSec)
LOW
I
IN
I
= 320nA
IN
7
). The result is divided by
= 500nA
9
11
13
March 14, 2005
FN8141.0
15
HIGH
-