Datasheet MAX1818 (Maxim) - 5
| 制造商 | Maxim |
| 描述 | 500mA, Low-Dropout Linear Regulator in SOT23 |
| 页数 / 页 | 9 / 5 — Typical Operating Characteristics (continued). SHORT-CIRCUIT CURRENT … |
| 文件格式/大小 | PDF / 1.5 Mb |
| 文件语言 | 英语 |
Typical Operating Characteristics (continued). SHORT-CIRCUIT CURRENT LIMIT. SHUTDOWN WAVEFORM. vs. SUPPLY VOLTAGE
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MAX1818 500mA Low-Dropout Linear Regulator in SOT23
Typical Operating Characteristics (continued)
(VIN = (VOUT + 500mV) or +2.5V, whichever is greater; SHDN = IN, CIN = 1μF, COUT = 3.3μF, TA = +25°C, unless otherwise noted.)
SHORT-CIRCUIT CURRENT LIMIT SHUTDOWN WAVEFORM vs. SUPPLY VOLTAGE
MAX1818 toc12 1.11 1.10 VOUT(NOM) = +2V SHUTDOWN 1.09 MAX1818 toc13 VOLTAGE 0 1.08 1.07 V 1.06 OUT 0 1.05 2V/div 1.04 1.03 1.02 POK 0 SHORT-CIRCUIT CURRENT LIMIT (A) 1.01 1.00 200µs/div 2.5 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V)
Pin Description PIN NAME FUNCTION
1 IN Regulator Input. Supply voltage can range from 2.5V to 5.5V. Bypass with a 1µF capacitor to GND (see Capacitor Selection and Regulator Stability). 2 POK Open-Drain POK Output. POK remains low while the output voltage (VOUT) is below the POK threshold. Connect a 100kΩ pull-up resistor from POK to OUT to obtain an output voltage. 3 SHDN Active-Low Shutdown Input. A logic low reduces supply current below 15µA. In shutdown, the POK output is low, and OUT is high impedance. Connect to IN for normal operation. 4 GND Ground 5 SET Voltage-Setting Input. Connect to GND for preset output. Connect to a resistive voltage-divider between OUT and GND to set the output voltage between 1.25V and 5.0V. 6 OUT Regulator Output. Sources up to 500mA. Bypass with a 3.3µF low-ESR capacitor to GND. Use a 4.7µF capacitor for output voltages below 2V.
Detailed Description
is pulled lower, which allows more current to pass to the The MAX1818 is a low-dropout, low-quiescent-current output and increases the output voltage. If the feedback linear regulator designed primarily for battery-powered voltage is too high, the pass-transistor gate is pulled up, applications. The device supplies loads up to 500mA and allowing less current to pass to the output. is available with preset output voltages. As illustrated in The output voltage is fed back through either an internal Figure 1, the MAX1818 consists of a 1.25V reference, resistive divider connected to OUT or an external resistor error amplifier, P-channel pass transistor, and internal network connected to SET. The Dual Mode comparator feedback voltage-divider. examines VSET and selects the feedback path. If VSET is The 1.25V reference is connected to the error amplifier, below 50mV, the internal feedback path is used and the which compares this reference with the feedback voltage output is regulated to the factory-preset voltage. and amplifies the difference. If the feedback voltage is Additional blocks include an output current limiter, thermal lower than the reference voltage, the pass-transistor gate sensor, and shutdown logic. www.maximintegrated.com Maxim Integrated │
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Typical Operating Characteristics (continued)
(VIN = (VOUT + 500mV) or +2.5V, whichever is greater; SHDN = IN, CIN = 1μF, COUT = 3.3μF, TA = +25°C, unless otherwise noted.)
SHORT-CIRCUIT CURRENT LIMIT SHUTDOWN WAVEFORM vs. SUPPLY VOLTAGE
MAX1818 toc12 1.11 1.10 VOUT(NOM) = +2V SHUTDOWN 1.09 MAX1818 toc13 VOLTAGE 0 1.08 1.07 V 1.06 OUT 0 1.05 2V/div 1.04 1.03 1.02 POK 0 SHORT-CIRCUIT CURRENT LIMIT (A) 1.01 1.00 200µs/div 2.5 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V)
Pin Description PIN NAME FUNCTION
1 IN Regulator Input. Supply voltage can range from 2.5V to 5.5V. Bypass with a 1µF capacitor to GND (see Capacitor Selection and Regulator Stability). 2 POK Open-Drain POK Output. POK remains low while the output voltage (VOUT) is below the POK threshold. Connect a 100kΩ pull-up resistor from POK to OUT to obtain an output voltage. 3 SHDN Active-Low Shutdown Input. A logic low reduces supply current below 15µA. In shutdown, the POK output is low, and OUT is high impedance. Connect to IN for normal operation. 4 GND Ground 5 SET Voltage-Setting Input. Connect to GND for preset output. Connect to a resistive voltage-divider between OUT and GND to set the output voltage between 1.25V and 5.0V. 6 OUT Regulator Output. Sources up to 500mA. Bypass with a 3.3µF low-ESR capacitor to GND. Use a 4.7µF capacitor for output voltages below 2V.
Detailed Description
is pulled lower, which allows more current to pass to the The MAX1818 is a low-dropout, low-quiescent-current output and increases the output voltage. If the feedback linear regulator designed primarily for battery-powered voltage is too high, the pass-transistor gate is pulled up, applications. The device supplies loads up to 500mA and allowing less current to pass to the output. is available with preset output voltages. As illustrated in The output voltage is fed back through either an internal Figure 1, the MAX1818 consists of a 1.25V reference, resistive divider connected to OUT or an external resistor error amplifier, P-channel pass transistor, and internal network connected to SET. The Dual Mode comparator feedback voltage-divider. examines VSET and selects the feedback path. If VSET is The 1.25V reference is connected to the error amplifier, below 50mV, the internal feedback path is used and the which compares this reference with the feedback voltage output is regulated to the factory-preset voltage. and amplifies the difference. If the feedback voltage is Additional blocks include an output current limiter, thermal lower than the reference voltage, the pass-transistor gate sensor, and shutdown logic. www.maximintegrated.com Maxim Integrated │
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