Datasheet

TLV2556
SLAS355A – DECEMBER 2001 – REVISED SEPTEMBER 2002
6
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external reference specifications
PARAMETER TEST CONDITIONS MIN TYP
†
MAX UNIT
Reference input voltage REF
V
CC
= 4.5 V to 5.5 V –0.1 0 0.1
V
Reference input voltage, REF–
V
CC
= 2.7 V to 3.6 V –0.1 0 0.1
V
Reference input voltage REF
V
CC
= 4.5 V to 5.5 V 2 V
CC
V
Reference input voltage, REF+
V
CC
= 2.7 V to 3.6 V 2 V
CC
V
External reference input volta
g
e difference,
V
CC
= 4.5 V to 5.5 V 1.9 V
CC
V
External
reference
in ut
voltage
difference
,
(REF+) – (REF–)
V
CC
= 2.7 V to 3.6 V 1.9 V
CC
V
External reference supply current
CS at0V
V
CC
= 4.5 V to 5.5 V 1
mA
External reference supply current CS at 0 V
V
CC
= 2.7 V to 3.6 V 0.7
mA
V5V
Static 1 MΩ
Reference input impedance
V
CC
= 5 V
During sampling/conversion 6 9 kΩ
Reference input impedance
V27V
Static 1 MΩ
V
CC
= 2.7 V
During sampling/conversion 6 9 kΩ
†
All typical values are at V
CC
= 5 V, T
A
= 25°C.
NOTE: Add a 0.1-µF capacitor between REF+ and REF– pins when external reference is used.
internal reference specifications
PARAMETER TEST CONDITIONS MIN TYP
†
MAX UNIT
Reference input voltage, REF– V
CC
= 2.7 V to 5.5 V, REF– = Analog GND 0 V
It l f dlt lt
V
CC
= 5.5 V, Internal 4.096-V
ref
selected 3.95 4.065 4.25
Internal reference delta voltage,
(REF+)
–
(REF
–
)
V
CC
= 5.5 V, Internal 2.048-V
ref
selected 1.95 2.019 2.1
V
(REF
+
)
–
(REF
–
)
V
CC
= 2.7 V, Internal 2.048-V
ref
selected 1.95 2.019 2.1
V
Internal reference start up time
V
CC
= 5 V
With 10 F load
20
ms
Internal reference start-up time
V
CC
= 2.7 V
With 10-µF load
20
ms
Internal reference temperature coefficient V
CC
= 2.7 V to 5.5 V ±50 PPM/°C
†
All typical values are at V
CC
= 5 V, T
A
= 25°C.
NOTE: When an internal reference is used, the following conditions are required:
a) Add 0.1-µF and 10-µF capacitors between REF+ and REF– pins.
b) REF– must be connected to analog GND (the ground pin of the ADC).