Datasheet

Test Setup
3-5
Testing
Operation of the 1-V EVM with input voltages from 2.7 V to 3 V requires in-
creasing the bias current for the TL431. Changing R5 to 180 Ω accomplishes
this at the expense of higher quiescent currents. Figures 3–4 and 3–5 show
the results of this modification.
Figure 3–4. Quiescent Current vs Output Current
0
2
4
6
8
10
12
14
16
0204060 80100
QUIESCIENT CURRENT
vs
OUTPUT CURRENT
V
IN
= 5 V
R5=180 Ω
I
O
– Output Current – mA
– Quiscent Current – mA
I
Q
Figure 3–5. Line Regulation from 2.7 V
1.033
1.0335
1.034
1.0345
1.035
1.0355
1.036
1.0365
1.037
1.0375
2 2.5 3 3.5
I
I
=95.6 mA
I
I
=12 mA
V
I
– Input Voltage – V
– Output Voltage – V
V
O
4 4.5 5
R5=180 Ω
LINE REGULATION FROM 2.7 V