Datasheet

LTC2157-12/
LTC2156-12/LTC2155-12
4
21576512f
INTERNAL REFERENCE CHARACTERISTICS
The l denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at T
A
= 25°C. (Note 5)
PARAMETER CONDITIONS MIN TYP MAX UNITS
V
CM
Output Voltage I
OUT
= 0 0.435 • V
DD
– 18mV 0.435 • V
DD
0.435 • V
DD
+ 18mV V
V
CM
Output Temperature Drift ±37 ppm/°C
V
CM
Output Resistance –1mA < I
OUT
< 1mA 4 Ω
V
REF
Output Voltage I
OUT
= 0 1.225 1.250 1.275 V
V
REF
Output Temperature Drift ±30 ppm/°C
V
REF
Output Resistance –400µA < I
OUT
< 1mA 7 Ω
V
REF
Line Regulation 1.7V < V
DD
< 1.9V 0.6 mV/V
DIGITAL INPUTS AND OUTPUTS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 5)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
ENCODE INPUTS (ENC
+
, ENC
–
)
V
ID
Differential Input Voltage (Note 8)
l
0.2 V
V
ICM
Common Mode Input Voltage Internally Set
Externally Set (Note 8)
l
1.1
1.2
1.5
V
V
R
IN
Input Resistance (See Figure 2) 10 kΩ
C
IN
Input Capacitance (Note 8) 2 pF
DIGITAL INPUTS (CS, SDI, SCK)
V
IH
High Level Input Voltage V
DD
= 1.8V
l
1.3 V
V
IL
Low Level Input Voltage V
DD
= 1.8V
l
0.6 V
I
IN
Input Current V
IN
= 0V to 3.6V
l
–10 10 µA
C
IN
Input Capacitance (Note 8) 3 pF
SDO OUTPUT (Open-Drain Output. Requires 2k Pull-Up Resistor if SDO Is Used)
R
OL
Logic Low Output Resistance to GND V
DD
= 1.8V, SDO = 0V 200 Ω
I
OH
Logic High Output Leakage Current SDO = 0V to 3.6V
l
–10 10 µA
C
OUT
Output Capacitance (Note 8) 4 pF
POWER REQUIREMENTS
The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. (Note 5)
SYMBOL PARAMETER CONDITIONS
LTC2157-12 LTC2156-12 LTC2155-12
UNITSMIN TYP MAX MIN TYP MAX MIN TYP MAX
V
DD
Analog Supply Voltage (Note 9)
l
1.7 1.8 1.9 1.7 1.8 1.9 1.7 1.8 1.9 V
OV
DD
Output Supply Voltage (Note 9)
l
1.7 1.8 1.9 1.7 1.8 1.9 1.7 1.8 1.9 V
I
VDD
Analog Supply Current
l
309 345 291 320 266 295 mA
I
OVDD
Digital Supply Current 1.75mA LVDS Mode
3.5mA LVDS Mode
l
l
40
68
46
76
38
66
45
75
37
65
42
74
mA
mA
P
DISS
Power Dissipation 1.75mA LVDS Mode
3.5mA LVDS Mode
l
l
628
679
704
758
592
643
657
711
545
596
607
665
mW
mW
P
SLEEP
Sleep Mode Power Clock Disabled
Clocked at f
S(MAX)
<5
<5
<5
<5
<5
<5
mW
mW
P
NAP
Nap Mode Power Clocked at f
S(MAX)
181 168 154 mW