Datasheet MAX8863, MAX8864 (Analog Devices) - 6
| Hersteller | Analog Devices |
| Beschreibung | Low-Dropout, 120mA Linear Regulators |
| Seiten / Seite | 10 / 6 — Pin Description. PIN. NAME. FUNCTION. Detailed Description. MAX8863. … |
| Dateiformat / Größe | PDF / 2.0 Mb |
| Dokumentensprache | Englisch |
Pin Description. PIN. NAME. FUNCTION. Detailed Description. MAX8863. MAX8864
Modelllinie für dieses Datenblatt
Textversion des Dokuments
link to page 6 MAX8863T/S/R, Low-Dropout, 120mA Linear Regulators MAX8864T/S/R
Pin Description PIN NAME FUNCTION
1 SHDN Active-Low Shutdown Input. A logic low reduces the supply current to 0.1nA. On the MAX8864, a logic low also causes the output voltage to discharge to GND. Connect to IN for normal operation. 2 GND Ground. This pin also functions as a heatsink. Solder to large pads or the circuit board ground plane to maximize thermal dissipation. 3 IN Regulator Input. Supply voltage can range from +2.5V to +6.5V. Bypass with 1µF to GND (see Capacitor Selection and Regulator Stability). 4 OUT Regulator Output. Fixed or adjustable from +1.25V to +6.5V. Sources up to 120mA. Bypass with a 1µF, < 0.2Ω typical ESR capacitor to GND. Feedback Input for Setting the Output Voltage. Connect to GND to set the output voltage to the preset 5 SET 2.80V (MAX886_R), 2.84V (MAX886_S), or 3.15V (MAX886_T). Connect to an external resistor- divider for adjustable-output operation.
Detailed Description
P-channel pass transistor. If the feedback voltage is lower The MAX8863/MAX8864 are low-dropout, low-quiescent- than the reference, the pass-transistor gate is pulled current linear regulators designed primarily for battery- lower, allowing more current to pass and increasing the powered applications. They supply an adjustable 1.25V output voltage. If the feedback voltage is too high, the to 6.5V output or a preselected 2.80V (MAX886_R), pass-transistor gate is pulled up, allowing less current to 2.84V (MAX886_S), or 3.15V (MAX886_T) output for load pass to the output. currents up to 120mA. As illustrated in Figure 1, these The output voltage is fed back through either an internal devices consist of a 1.25V reference, error amplifier, resistor voltage divider connected to the OUT pin, or an MOSFET driver, P-channel pass transistor, Dual Mode™ external resistor network connected to the SET pin. The comparator, and internal feedback voltage divider. Dual Mode comparator examines the SET voltage and The 1.25V bandgap reference is connected to the error selects the feedback path. If SET is below 60mV, internal amplifier’s inverting input. The error amplifier compares feedback is used and the output voltage is regulated to this reference with the selected feedback voltage and the preset output voltage. Additional blocks include a amplifies the difference. The MOSFET driver reads the current limiter, reverse battery protection, thermal sensor, error signal and applies the appropriate drive to the and shutdown logic. IN REVERSE BATTERY SHDN PROTECTION ERROR MOS DRIVER P AMP WITH ILIMIT SHUTDOWN
MAX8863
LOGIC N OUT
MAX8864
* SET THERMAL 1.25V SENSOR REF DUAL-MODE COMPARATOR 60mV GND * AUTO-DISCHARGE, MAX8864 ONLY Figure 1. Functional Diagram www.maximintegrated.com Maxim Integrated │ 6
Pin Description PIN NAME FUNCTION
1 SHDN Active-Low Shutdown Input. A logic low reduces the supply current to 0.1nA. On the MAX8864, a logic low also causes the output voltage to discharge to GND. Connect to IN for normal operation. 2 GND Ground. This pin also functions as a heatsink. Solder to large pads or the circuit board ground plane to maximize thermal dissipation. 3 IN Regulator Input. Supply voltage can range from +2.5V to +6.5V. Bypass with 1µF to GND (see Capacitor Selection and Regulator Stability). 4 OUT Regulator Output. Fixed or adjustable from +1.25V to +6.5V. Sources up to 120mA. Bypass with a 1µF, < 0.2Ω typical ESR capacitor to GND. Feedback Input for Setting the Output Voltage. Connect to GND to set the output voltage to the preset 5 SET 2.80V (MAX886_R), 2.84V (MAX886_S), or 3.15V (MAX886_T). Connect to an external resistor- divider for adjustable-output operation.
Detailed Description
P-channel pass transistor. If the feedback voltage is lower The MAX8863/MAX8864 are low-dropout, low-quiescent- than the reference, the pass-transistor gate is pulled current linear regulators designed primarily for battery- lower, allowing more current to pass and increasing the powered applications. They supply an adjustable 1.25V output voltage. If the feedback voltage is too high, the to 6.5V output or a preselected 2.80V (MAX886_R), pass-transistor gate is pulled up, allowing less current to 2.84V (MAX886_S), or 3.15V (MAX886_T) output for load pass to the output. currents up to 120mA. As illustrated in Figure 1, these The output voltage is fed back through either an internal devices consist of a 1.25V reference, error amplifier, resistor voltage divider connected to the OUT pin, or an MOSFET driver, P-channel pass transistor, Dual Mode™ external resistor network connected to the SET pin. The comparator, and internal feedback voltage divider. Dual Mode comparator examines the SET voltage and The 1.25V bandgap reference is connected to the error selects the feedback path. If SET is below 60mV, internal amplifier’s inverting input. The error amplifier compares feedback is used and the output voltage is regulated to this reference with the selected feedback voltage and the preset output voltage. Additional blocks include a amplifies the difference. The MOSFET driver reads the current limiter, reverse battery protection, thermal sensor, error signal and applies the appropriate drive to the and shutdown logic. IN REVERSE BATTERY SHDN PROTECTION ERROR MOS DRIVER P AMP WITH ILIMIT SHUTDOWN
MAX8863
LOGIC N OUT
MAX8864
* SET THERMAL 1.25V SENSOR REF DUAL-MODE COMPARATOR 60mV GND * AUTO-DISCHARGE, MAX8864 ONLY Figure 1. Functional Diagram www.maximintegrated.com Maxim Integrated │ 6