Datasheet
MAX9000–MAX9005
Reference Bypassing
While the internal reference is stable with capacitive
loads up to 100nF, it does not require an output capaci-
tor for stability. However, in applications where the load
or the supply could experience large step changes, an
output capacitor reduces the amount of overshoot and
improves the circuit’s transient response.
Comparator Input Stage
The comparator’s input bias current is typically 8nA. To
reduce the offset error caused by the bias current flow-
ing through the external source impedance, match the
effective impedance seen by each input. High source
impedance together with the comparator’s input capaci-
tance can increase the propagation delay through the
comparator. The outputs do not undergo phase rever-
sal when the input common-mode range is exceeded,
and the input impedance is relatively constant for input
voltages within both supply rails.
Comparator Hysteresis
Built-in ±2mV hysteresis improves the comparator’s
noise immunity. It prevents unstable outputs with slow-
moving or noisy input signals. If additional hysteresis is
required, add positive feedback as shown in Figure 6.
This configuration increases the hysteresis band to
desired levels, but also increases power consumption
and slows down the output response.
Low-Power, High-Speed, Single-Supply
Op Amp + Comparator + Reference ICs
14 ______________________________________________________________________________________
2µs/div
V
IN
50mV/
div
V
OUT
50mV/
div
MAX9000-FIG03
Figure 3. MAX9000/MAX9001/MAX9002 Op-Amp Small-Signal
Transient Response with Capacitive Load (C
L
= 510pF) and
Isolation Resistor (R
ISO
= 91
Ω
)
Figure 5. Compensation for Input Capacitance
R1
R2
2pF TO 10pF
AOUT
AIN+
2µs/div
V
IN
50mV/
div
V
OUT
50mV/
div
MAX9000-FIG04
V
DD
= +1
C
L
= 510pF
Figure 4. MAX9000/MAX9001/MAX9002 Op-Amp Small-Signal
Transient Response with Capacitive Load (C
L
= 510pF) and
No Isolation Resistor
REF
R2
R1
COUT
V
IN
Figure 6. External Hysteresis