Reference voltage and reference current generation, Ata6264 [preliminary – Atmel ATA6264 User Manual
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4929B–AUTO–01/07
ATA6264 [Preliminary]
14. Reference Voltage and Reference Current Generation
The pin IREF is an output derived directly from the chip’s internal reference voltage. This refer-
ence source is a band gap. All internally used precise voltages are derived from this band-gap
voltage. At pin IREF a reference resistor of 12.4 k
Ω
has to be applied, providing a reference cur-
rent. All internally used precise currents are derived from this current. In case of a missing
resistor at IREF, the regulators will stop. The power-sequencing block still operates as specified.
A defect of the band-gap reference source can be detected by a microcontroller by comparing
the voltage at IREF with the voltage at pin VINT (Internal 5V supply), because V
VINT
is derived
from a different band gap.
Necessary for operation:
V
EVZ
= 5.5V to 40V or V
K30
= 3.85V to 40V
Operating conditions of all other supply pins:
V
SAT
, V
PERI
and V
CORE
are within functional range limits, T
j
= –40°C to +150°C
Other pins:
As defined in
Section 4. ”Functional Range” on page 8
Table 14-1.
Truth Table for VINT
State
K30GOOD
(V
K30
> 4.2V to 5V)
K15GOOD
(V
K15
> 3V to 4V)
V
EVZ
V
VINT
1
Low
Low
0
OFF
2
High
Low
0
OFF
3
Low
High
0
OFF
4
High
High
V
EVZ
< V
K30
ON (Supply: K30)
5
Low
Low
V
EVZ
> 5.5V
ON (Supply: EVZ) – only valid if VINT was
already enabled via state #4
6
High
Low
V
EVZ
> 5.5V
ON (Supply: EVZ) – only valid if VINT was
already enabled via state #4
7
Low
High
V
EVZ
> 5.5V
ON (Supply: EVZ) – only valid if VINT was
already enabled via state #4
8
High
High
V
EVZ
> V
K30
ON (Supply: K30)
Table 14-2.
Electrical Characteristics – Reference Voltage and Reference Current Generation
No. Parameters
Test Conditions
Pin
Symbol
Min
Typ.
Max.
Unit
Type*
13.1 Reference voltage V
IREF
IREF
V
IREF
1.24 ± 4%
V
A
13.2 Reference current IREF
IREF
I
IREF
100 ± 4%
µA
A
13.3a Voltage at VINT
V
K30
> V
EVZ
V
K30
= VK30GOOD to 5V
VINT
V
VINT
3.35
5.47
V
A
13.3b Voltage at VINT
V
K30
> V
EVZ
, V
K30
= 5V to 6V
VINT
V
VINT
3.7
5.47
V
A
13.3c Voltage at VINT
V
K30
> V
EVZ
, V
K30
= 6V
IREF
V
IREF
4.2
5.47
V
A
13.3d Voltage at VINT
V
EVZ
> V
K30
V
K30
= 0V, V
EVZ
> 6V
IREF
V
IREF
4.2
5.47
V
A
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter