AAT1415-Q8-T AAT [Advanced Analog Technology, Inc.], AAT1415-Q8-T Datasheet - Page 25

• Manufacturer Part Number: AAT1415-Q8-T
• Description: FIVE-CHANNEL DC-DC CONVERTER WITH A 2.5V LDO
• Manufacturer: AAT [Advanced Analog Technology, Inc.]

Soft Start Waveform
Figure 7. Timing Chart of Soft-Start
Advanced Analog Technology, Inc.
–
–
Advanced Analog Technology, Inc . –
台 灣 類 比 科 技 股 份 有 限 公 司
Page 25 of 32
Version 3.00
Low-Voltage Startup Oscillator
The
reference voltage circuitry receives power from VDD
and do not function when VDD is less than 2.5V. To
ensure low voltage startup, the CH1 employs a
low-voltage startup oscillator (about 200kHz) that
activates at 1.2V if a Schottky diode is connected from
PWR to OUT1. The startup oscillator drives the internal
NMOS at SW1 until VDD reaches 2.5V, at which point
voltage control is passed to the normal oscillator
(current-mode PWM circuitry). At low input voltages,
the CH1 can have difficulty starting into heavy loads.
AAT1415/AAT1415A
–
Figure 8. Oscillator Frequency
AAT1415/AAT1415A
internal
control
May 2008
and