Datasheet

LM12454, LM12458, LM12H458
SNAS079A –MAY 2004–REVISED FEBRUARY 2006 www.ti.com
INTERNAL REFERENCE CHARACTERISTICS
(1) (2)
The following specifications apply to the LM12454, LM12458, and LM12H458 for V
A
+ = V
D
+ = 5V unless otherwise specified.
Boldface limits apply for T
A
= T
J
= T
MIN
to T
MAX
; all other limits T
A
= T
J
= 25°C.
Typical Limits
Symbol Parameter Conditions Units
(3) (4)
V
REFOUT
Internal Reference Output Voltage 2.5 2.5 ±4% V (max)
Internal Reference Temperature
ΔV
REF
/ΔT 40 ppm/°C
Coefficient
Sourcing (0 < I
L
≤ +4 mA) 0.2 %/mA (max)
Δ
REF
/ΔI
L
Internal Reference Load Regulation
Sinking (−1 ≤ I
IL
< 0 mA) 1.2 %/mA (max)
ΔV
REF
Line Regulation 4.5V ≤ V
A
+ ≤ 5.5V 3 20 mV (max)
I
SC
Internal Reference Short Circuit Current V
REFOUT
= 0V 13 25 mA (max)
ΔV
REF
/Δt Long Term Stability 200 ppm/kHr
V
A
+ = V
D
+ = 0V →
t
SU
Internal Reference Start-Up Time 10 ms
5V, C
L
= 100 μF
(1) Two on-chip diodes are tied to each analog input through a series resistor, as shown below. Input voltage magnitude up to 5V above
V
A
+ or 5V below GND will not damage the LM12454 or the LM12(H)458. However, errors in the A/D conversion can occur if these
diodes are forward biased by more than 100 mV. As an example, if V
A
+ is 4.5 V
DC
, full-scale input voltage must be ≤4.6 V
DC
to ensure
accurate conversions. See Figure 3
(2) V
A
+ and V
D
+ must be connected together to the same power supply voltage and bypassed with separate capacitors at each V
+
pin to
assure conversion/comparison accuracy.
(3) Typical figures are at T
A
= 25°C and represent most likely parametric norm.
(4) Limits are to AOQL (Average Output Quality Level).
DIGITAL CHARACTERISTICS
(1) (2)
The following specifications apply to the LM12454, LM12458, and LM12H458 for V
A
+ = V
D
+ = 5V, unless otherwise specified.
Boldface limits apply for T
A
= T
J
= T
MIN
to T
MAX
; all other limits T
A
= T
J
= 25°C.
Typical Limits
Symbol Parameter Conditions Units
(3) (4)
V
IN(1)
Logical “1” Input Voltage V
A
+ = V
D
+ = 5.5V 2.0 V (min)
V
IN(0)
Logical “0” Input Voltage V
A
+ = V
D
+ = 4.5V 0.8 V (max)
I
IN(1)
Logical “1” Input Current V
IN
= 5V 0.005 1.0 μA (max)
I
IN(0)
Logical “0” Input Current V
IN
= 0V −0.005 −1.0 μA (max)
C
IN
D0–D15 Input Capacitance 6 pF
V
A
+ = V
D
+ = 4.5V
V
OUT(1)
Logical “1” Output Voltage I
OUT
= −360 μA 2.4 V (min)
I
OUT
= −10 μA 4.25 V (min)
V
A
+ = V
D
+ = 4.5V
V
OUT(0)
Logical “0” Output Voltage 0.4 V (max)
I
OUT
= 1.6 mA
V
OUT
= 0V −0.01 −3.0 μA (max)
I
OUT
TRI-STATE
®
Output Leakage Current
V
OUT
= 5V 0.01 3.0 μA (max)
(1) Two on-chip diodes are tied to each analog input through a series resistor, as shown below. Input voltage magnitude up to 5V above
V
A
+ or 5V below GND will not damage the LM12454 or the LM12(H)458. However, errors in the A/D conversion can occur if these
diodes are forward biased by more than 100 mV. As an example, if V
A
+ is 4.5 V
DC
, full-scale input voltage must be ≤4.6 V
DC
to ensure
accurate conversions. See Figure 3
(2) V
A
+ and V
D
+ must be connected together to the same power supply voltage and bypassed with separate capacitors at each V
+
pin to
assure conversion/comparison accuracy.
(3) Typical figures are at T
A
= 25°C and represent most likely parametric norm.
(4) Limits are to AOQL (Average Output Quality Level).
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