4
LTC2420
The ● denotes specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. (Note 3)
f
EOSC
External Oscillator Frequency Range 20-Bit Effective Resolution ● 2.56 307.2 kHz
12-Bit Effective Resolution
● 2.56 2.048 MHz
t
HEO
External Oscillator High Period ● 0.2 390 µs
t
LEO
External Oscillator Low Period ● 0.2 390 µs
t
CONV
Conversion Time F
O
= 0V ● 130.86 133.53 136.20 ms
F
O
= V
CC
● 157.03 160.23 163.44 ms
External Oscillator (Note 11)
● 20510/f
EOSC
(in kHz) ms
f
ISCK
Internal SCK Frequency Internal Oscillator (Note 10) 19.2 kHz
External Oscillator (Notes 10, 11) f
EOSC
/8 kHz
D
ISCK
Internal SCK Duty Cycle (Note 10) 45 55 %
f
ESCK
External SCK Frequency Range (Note 9) ● 2000 kHz
t
LESCK
External SCK Low Period (Note 9) ● 250 ns
t
HESCK
External SCK High Period (Note 9) ● 250 ns
t
DOUT_ISCK
Internal SCK 24-Bit Data Output Time Internal Oscillator (Notes 10, 12) ● 1.23 1.25 1.28 ms
External Oscillator (Notes 10, 11)
● 192/f
EOSC
(in kHz) ms
t
DOUT_ESCK
External SCK 24-Bit Data Output Time (Note 9) ● 24/f
ESCK
(in kHz) ms
t
1
CS ↓ to SDO Low Z ● 0 150 ns
t2 CS ↑ to SDO High Z ● 0 150 ns
t3 CS ↓ to SCK ↓ (Note 10) ● 0 150 ns
t4 CS ↓ to SCK ↑ (Note 9) ● 50 ns
t
KQMAX
SCK ↓ to SDO Valid ● 200 ns
t
KQMIN
SDO Hold After SCK ↓ (Note 5) ● 15 ns
t
5
SCK Set-Up Before CS ↓ ● 50 ns
t
6
SCK Hold After CS ↓ ● 50 ns
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Note 1: Absolute Maximum Ratings are those values beyond which the
life of the device may be impaired.
Note 2: All voltage values are with respect to GND.
Note 3: All voltages are with respect to GND. V
CC
= 2.7 to 5.5V unless
otherwise specified. R
SOURCE
= 0Ω.
Note 4: Internal Conversion Clock source with the F
O
pin tied
to GND or to V
CC
or to external conversion clock source with
f
EOSC
= 153600Hz unless otherwise specified.
Note 5: Guaranteed by design, not subject to test.
Note 6: Integral nonlinearity is defined as the deviation of a code from
a straight line passing through the actual endpoints of the transfer
curve. The deviation is measured from the center of the quantization
band.
Note 7: F
O
= 0V (internal oscillator) or f
EOSC
= 153600Hz ±2%
(external oscillator).
Note 8: F
O
= V
CC
(internal oscillator) or f
EOSC
= 128000Hz ±2%
(external oscillator).
Note 9: The converter is in external SCK mode of operation such that
the SCK pin is used as digital input. The frequency of the clock signal
driving SCK during the data output is f
ESCK
and is expressed in kHz.
Note 10: The converter is in internal SCK mode of operation such that
the SCK pin is used as digital output. In this mode of operation the
SCK pin has a total equivalent load capacitance C
LOAD
= 20pF.
Note 11: The external oscillator is connected to the F
O
pin. The external
oscillator frequency, f
EOSC
, is expressed in kHz.
Note 12: The converter uses the internal oscillator.
F
O
= 0V or F
O
= V
CC
.
Note 13: The output noise includes the contribution of the internal
calibration operations.
Note 14: For reference voltage values V
REF
> 2.5V the extended input
of –0.125 • V
REF
to 1.125 • V
REF
is limited by the absolute maximum
rating of the Analog Input Voltage pin (Pin 3). For 2.5V < V
REF
≤
0.267V + 0.89 • V
CC
the input voltage range is –0.3V to 1.125 • V
REF
.
For 0.267V + 0.89 • V
CC
< V
REF
≤ V
CC
the input voltage range is –0.3V
to V
CC
+ 0.3V.
Note 15: V
CC
(DC) = 4.1V, V
CC
(AC) = 2.8V
P-P
.
TI I G CHARACTERISTICS
UW
