Datasheet MAX1684, MAX1685 (Maxim) - 7
| Hersteller | Maxim |
| Beschreibung | Low-Noise, 14V Input, 1A, PWM Step-Down Converters |
| Seiten / Seite | 14 / 7 — Low-Noise, 14V Input, 1A, PWM. Step-Down Converters. MAX1684/MAX1685. … |
| Dateiformat / Größe | PDF / 301 Kb |
| Dokumentensprache | Englisch |
Low-Noise, 14V Input, 1A, PWM. Step-Down Converters. MAX1684/MAX1685. Typical Operating Characteristics (continued)
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Low-Noise, 14V Input, 1A, PWM Step-Down Converters MAX1684/MAX1685 Typical Operating Characteristics (continued)
(Circuit of Figure 1, TA = +25°C, unless otherwise noted.)
LINE-TRANSIENT RESPONSE STARTUP CURRENT
MAX1684/85 toc19 MAX1684/85 toc20 V V IN SHDN 5V/div 5V/div 0V VOUT I 100mV/div IN 50mA/div 2ms/div 10ms/div MAX1684, ILOAD = 100mA, VIN = 5V TO 10V, MAX1684, ILOAD = 100mA, VOUT = 3.3V, SYNC/PWM = 3.3V VIN = 5V, CILIM/SS = 0.1µF, SYNC/PWM = 3.3V
Pin Description PIN NAME FUNCTION
1 CVH High-Side MOSFET Gate Bias. Bias voltage for P-channel switch. Bypass to IN with a 0.1µF capacitor. Analog Supply Voltage Input. Connect to IN with a 0.2in metal trace. Bypass to PGND with a 0.1µF 2 AIN capacitor. 3 IN Supply Voltage Input Logic Supply Voltage Output and IC Logic Supply. Sources 5mA for external loads. Bypass to AGND 4 CVL with 1µF capacitor. 5 AGND Analog Ground Reference Output. 1.25V reference output supplies 10µA for external loads. Bypass to AGND with 0.1µF 6 REF capacitor. Dual-Mode Feedback Input. Connect FB to VOUT for 1.25V output. Connect to an external resistor divider 7 FB to adjust the output voltage. Connect to AGND to set output voltage to 3.3V. 8 CC Integrator Capacitor Connection. Connect a 0.01µF capacitor to AGND. SYNC/PWM Input: For synchronized-PWM operation, drive with TTL level, 50% square wave. 9 SYNC/PWM Connect to CVL for PWM mode. Connect to AGND for normal mode. 10 ILIM/SS Current-Limit Adjust/Soft-Start Input. See the Current Limit and Soft-Start section. Standby Control Input. Connect to CVL for normal operation. Connect to AGND for low-power mode 11 STBY (Table 1). This pin overrides SYNC/PWM setting. Bootstrap Input. Connection for the bootstrap switch and internal feedback path. Connect BOOT to VOUT 12 BOOT for VOUT < 5.5V. Connect BOOT to AGND for VOUT > 5.5V. 13, 14 LX Inductor Connection. Drain for internal P-channel MOSFETs. Connect inductor from LX to OUT. 15 SHDN Active-Low Shutdown Input. Connect to ground for shutdown. SHDN can withstand the input voltage. 16 PGND Power Ground
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(Circuit of Figure 1, TA = +25°C, unless otherwise noted.)
LINE-TRANSIENT RESPONSE STARTUP CURRENT
MAX1684/85 toc19 MAX1684/85 toc20 V V IN SHDN 5V/div 5V/div 0V VOUT I 100mV/div IN 50mA/div 2ms/div 10ms/div MAX1684, ILOAD = 100mA, VIN = 5V TO 10V, MAX1684, ILOAD = 100mA, VOUT = 3.3V, SYNC/PWM = 3.3V VIN = 5V, CILIM/SS = 0.1µF, SYNC/PWM = 3.3V
Pin Description PIN NAME FUNCTION
1 CVH High-Side MOSFET Gate Bias. Bias voltage for P-channel switch. Bypass to IN with a 0.1µF capacitor. Analog Supply Voltage Input. Connect to IN with a 0.2in metal trace. Bypass to PGND with a 0.1µF 2 AIN capacitor. 3 IN Supply Voltage Input Logic Supply Voltage Output and IC Logic Supply. Sources 5mA for external loads. Bypass to AGND 4 CVL with 1µF capacitor. 5 AGND Analog Ground Reference Output. 1.25V reference output supplies 10µA for external loads. Bypass to AGND with 0.1µF 6 REF capacitor. Dual-Mode Feedback Input. Connect FB to VOUT for 1.25V output. Connect to an external resistor divider 7 FB to adjust the output voltage. Connect to AGND to set output voltage to 3.3V. 8 CC Integrator Capacitor Connection. Connect a 0.01µF capacitor to AGND. SYNC/PWM Input: For synchronized-PWM operation, drive with TTL level, 50% square wave. 9 SYNC/PWM Connect to CVL for PWM mode. Connect to AGND for normal mode. 10 ILIM/SS Current-Limit Adjust/Soft-Start Input. See the Current Limit and Soft-Start section. Standby Control Input. Connect to CVL for normal operation. Connect to AGND for low-power mode 11 STBY (Table 1). This pin overrides SYNC/PWM setting. Bootstrap Input. Connection for the bootstrap switch and internal feedback path. Connect BOOT to VOUT 12 BOOT for VOUT < 5.5V. Connect BOOT to AGND for VOUT > 5.5V. 13, 14 LX Inductor Connection. Drain for internal P-channel MOSFETs. Connect inductor from LX to OUT. 15 SHDN Active-Low Shutdown Input. Connect to ground for shutdown. SHDN can withstand the input voltage. 16 PGND Power Ground
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