Datasheet
3Maxim Integrated
Digitally-Programmed, Dual
2nd-Order Continuous Lowpass Filter
MAX270/MAX271
ELECTRICAL CHARACTERISTICS (continued)
(V+ = +5V, V- = -5V; T
A
= +25NC, unless otherwise noted.)
Note 1: All internal amplifiers limited to 2MHz bandwidth.
Note 2: Only filter A tested for these parameters.
Note 3: Spurious-Free Dynamic Range is the ratio of the fundamental to the largest of any harmonic or noise spur in dB.
Note 4: Includes T/H propagation delays. With 5kω, parallel 100pF load.
Note 5: ±2V input step settling 0.1% with 5kω parallel 100pF load.
Note 6: T/H pin toggled at sampling rate, 50% duty cycle.
Note 7: THD and SFDR specifications for T/H include contributions from filter.
Note 8: Digital pins include SHDN, WR, CS, A0, D0–D6 (MAX270) and SHDN, T/H, A/B, WR, T/H EN, CS, A0, A1, D0–D6, T/H
(MAX271).
Note 9: Input of uncommitted op amp disconnected with a 5kω feedback resistor from input to output.
Note 10: WR, CS, A0, D0–D6 held at +5V; V
SHDN
= 0V (MAX270). WR, CS, A0, A1, D0–D6, T/H, T/H, A/B, T/H, MODE held at
+5V; V
SHDN
= 0V (MAX271).
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DYNAMIC FILTER CHARACTERISTICS (MAX270)
Total Harmonic Distortion
THD
f
C
code = 44 (2.01kHz typ), V
IN
= 3.5V
P-P
at
390.625Hz (Notes 2 and 3)
-70
dBSignal Noise Plus Distortion
SINAD
73
Spurious-Free Dynamic Range
SFDR
70
UNCOMMITTED AMPLIFIER (MAX270)
Slew Rate 1.2
V/Fs
Bandwidth 2 MHz
TRACK AND HOLD (MAX271)
Hold Settling Time To 0.1% (Note 4) 500 ns
Acquisition Time To 0.1% (Note 5) 1.8
Fs
Hold Step 1 mV
Droop Rate T
A
= T
MIN
to T
MAX
30
FV/Fs
Offset Voltage at T/H OUT Includes filter offset -6 +6 mV
T/H OUT Disabled Output Leakage
Current
T
A
= T
MIN
to T
MAX
, V
T/H
= 0V (Track Mode) -10 +10
FA
Total Harmonic Distortion
THD
f
C
code = 44 (2.01kHz typ), V
IN
= 3.5V
P-P
at
390.625Hz, sampling rate = 50kHz
(Notes 2, 6, 7)
-70
dB
Spurious-Free Dynamic Range
SFDR
70
DIGITAL INPUTS
Digital Input High Voltage T
A
= T
MIN
to T
MAX
(Note 8) 2.4
V
Digital Input Low Voltage 0.8
Digital Input Current
T
A
= T
MIN
to T
MAX
, digital input held at Q5V,
includes MODE (MAX271)(Note 8)
-1 +1
FA
POWER REQUIREMENTS
Supply Voltage Range
Q2.375
to Q8
V
Supply Current T
A
= T
MIN
to T
MAX
(Note 9) 6.5 mA
Shutdown Supply Current T
A
= T
MIN
to T
MAX
(Note 10) 15
FA
Power-Supply Rejection Ratio at
1kHz
PSRR
f
C
code = 0 (1kHz typ), V+ = 5V
DC
+
10mV
P-P
at 1kHz
30 dB