MAX15004 View Datasheet(PDF) - Maxim Integrated

Part Name

Description

MFG CO.

MAX15004

4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers

Maxim Integrated 

MAX15004A/B-MAX15005A/B

most accuracy, CT should include all additional stray

capacitance (typically 25pF to 35pF).

The MAX15004A/B is a 50% maximum duty-cycle part,

while the MAX15005A/B is a 100% maximum duty-cycle

part:

fOUT

=

1

2

fOSC

for the MAX15004A/B and:

fOUT = fOSC

for the MAX15005A/B.

The MAX15004A/B/MAX15005A/B can be synchronized

using an external clock at the SYNC input. For proper

frequency synchronization, SYNC’s input frequency must

be at least 102% of the programmed internal oscillator

frequency. Connect SYNC to SGND when not using an

external clock. A rising clock edge on SYNC is interpreted

as a synchronization input. If the SYNC signal is lost,

4.5V to 40V Input Automotive

Flyback/Boost/SEPIC

Power-Supply Controllers

the internal oscillator takes control of the switching rate,

returning the switching frequency to that set by RC net-

work connected to RTCT. This maintains output regulation

even with intermittent SYNC signals.

n-Channel MOSFET Driver

OUT drives the gate of an external n-channel MOSFET.

The driver is powered by the internal regulator (VCC),

internally set to approximately 7.4V. The regulated VCC

voltage keeps the OUT voltage below the maximum gate

voltage rating of the external MOSFET. OUT can source

750mA and sink 1000mA peak current. The average

current sourced by OUT depends on the switching

frequency and total gate charge of the external MOSFET.

Error Amplifier

The MAX15004A/B/MAX15005A/B include an internal

error amplifier. The noninverting input of the error ampli-

fier is connected to the internal 1.228V reference and

feedback is provided at the inverting input. High 100dB

open-loop gain and 1.6MHz unity-gain bandwidth allow

good closed-loop bandwidth and transient response.

RTCT

CLKINT

SYNC

OUT

RTCT

CLKINT

SYNC

OUT

MAX15004A/B (DMAX = 50%)

WITH SYNC WITHOUT

INPUT

SYNC INPUT

D = 50%

MAX15005A/B (DMAX = 81%)

D = 50%

WITH SYNC

INPUT

WITHOUT

SYNC INPUT

D = 81.25%

D = 80%

Figure 2. Timing Diagram for Internal Oscillator vs. External SYNC and DMAX Behavior

www.maximintegrated.com

Maxim Integrated │  13

Share Link: