MAX9001 Maxim, MAX9001 Datasheet - Page 14

• Manufacturer Part Number: MAX9001
• Description: The MAX9000 family features the combination of a high-speed operational amplifier, a 185ns comparator, and a precision 1
• Manufacturer: Maxim

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.
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
Low-Power, High-Speed, Single-Supply
Op Amp + Comparator + Reference ICs
Figure 3. MAX9000/MAX9001/MAX9002 Op-Amp Small-Signal
Transient Response with Capacitive Load (C
Isolation Resistor (R
Figure 5. Compensation for Input Capacitance
14
50mV/
50mV/
AIN+
______________________________________________________________________________________
V
OUT
V
div
div
IN
R1
ISO
2pF TO 10pF
= 91 Ω )
R2
Comparator Input Stage
2 s/div
Reference Bypassing
L
= 510pF) and
AOUT
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.
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.
Figure 4. MAX9000/MAX9001/MAX9002 Op-Amp Small-Signal
Transient Response with Capacitive Load (C
No Isolation Resistor
Figure 6. External Hysteresis
50mV/
50mV/
V
V
IN
OUT
V
div
div
IN
R1
V
C
DD
L
= 510pF
= +1
REF
2 s/div
Comparator Hysteresis
R2
L
= 510pF) and
COUT