Datasheet MAX4322, MAX432, MAX4326, MAX4327, MAX4329 (Maxim) - 10

Single/Dual/Quad, Low-Cost, UCSP/SOT23, Low-Power, Rail-to-Rail I/O Op Amps
Driving a capacitive load can cause instability in most V - 1.8V I = DIFF high-speed op amps, especially those with low quies- BIAS 2kΩ cent current. The MAX4322/MAX4323/MAX4326/ MAX4327/MAX4329 have a high tolerance for capaci-
Rail-to-Rail Output Stage
tive loads. They are stable with capacitive loads up to The minimum output voltage is within millivolts of 500pF. Figure 4 gives the stable operating region for ground for single-supply operation where the load is capacitive loads. Figures 5 and 6 show the response referenced to ground (VEE). Figure 3 shows the input with capacitive loads and the results of adding an iso- voltage range and output voltage swing of a MAX4322 lation resistor in series with the output (Figure 7). The connected as a voltage follower. With a 3V supply and resistor improves the circuit’s phase margin by isolat- the load tied to ground, the output swings from 0 to ing the load capacitor from the op amp’s output. 2.90V. The maximum output voltage swing depends on the load, but is within 350mV of a 5V supply, even with
Power-Up and Shutdown Mode
the maximum load (500Ω to ground). The MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 amplifiers typically settle within 1µs after power-up. 10,000 VCC = 3V IN AV = +1
UNSTABLE REGION
1000 VOLTAGE (1V/div) OUT CAPACITIVE LOAD (pF) RL TO VEE VOUT = VCC / 2 100 100 1k 10k 100k 2µs/div RESISTIVE LOAD (Ω) Figure 3. Rail-to-Rail Input/Output Voltage Range Figure 4. Capacitive-Load Stability A A V = +1 V = +1 C C L = 500pF L = 1000pF RS = 39Ω IN IN VOLTAGE (50mV/div) VOLTAGE (50mV/div) OUT OUT
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
400ns/div 400ns/div Figure 5. Small-Signal Transient Response with Figure 6. Transient Response to Capacitive Load with Capacitive Load Isolation Resistor
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