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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 12.4kΩ 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 VVINT is derived
from a different band gap.
Necessary for operation:
VEVZ = 5.5V to 40V or VK30 = 3.85V to 40V
Operating conditions of all other supply pins:
VSAT, VPERI and VCORE are within functional range limits, Tj = –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
(VK30>4.2V to 5V)
K15GOOD
(VK15>3Vto4V) V
EVZ VVINT
1Low Low 0 OFF
2High Low 0 OFF
3 Low High 0 OFF
4 High High VEVZ < VK30 ON (Supply: K30)
5Low LowV
EVZ > 5.5V ON (Supply: EVZ) – only valid if VINT was
already enabled via state #4
6High LowV
EVZ > 5.5V ON (Supply: EVZ) – only valid if VINT was
already enabled via state #4
7 Low High VEVZ > 5.5V ON (Supply: EVZ) – only valid if VINT was
already enabled via state #4
8 High High VEVZ > VK30 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 VIREF IREF VIREF 1.24± 4% V A
13.2 Reference current IREF IREF IIREF 100 ± 4% µA A
13.3a Voltage at VINT VK30 > VEVZ
VK30 = VK30GOOD to 5V VINT VVINT 3.35 5.47 V A
13.3b Voltage at VINT VK30 > VEVZ, VK30 = 5V to 6V VINT VVINT 3.7 5.47 V A
13.3c Voltage at VINT VK30 > VEVZ, VK30 = 6V IREF VIREF 4.2 5.47 V A
13.3d Voltage at VINT VEVZ > VK30
VK30 = 0V, VEVZ > 6V IREF VIREF 4.2 5.47 V A
*) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter