The MAX8513/MAX8514 integrate a voltage-mode
PWM step-down DC-DC controller and two LDO controllers,
a voltage monitor, and a power-on reset for the
lowest-cost power-supply and monitoring solution for
xDSL modems, routers, gateways, and set-top boxes.
The DC-DC controller switching frequency can be set
with an external resistor from 300kHz to 1.4MHz, to allow
for the optimization of cost, size, and efficiency. For noisesensitive
applications, the DC-DC controller can also be
synchronized to an external clock, minimizing noise interference.
Operation above 1.1MHz reduces noise for high
data-rate xDSL applications. An adjustable soft-start and
adjustable foldback current limit provide reliable startup
and fault protection. The DC-DC controller output voltage
can be set externally to a voltage from 1.25V to 5.5V.
Current limiting is accomplished by inductor current sensing
for improved efficiency, or by an external sense resistor
for better accuracy.
The MAX8513/MAX8514s' first LDO controller is
designed to provide a low-cost, high-current regulated
output from 0.8V to 5.5V using an N-channel MOSFET or
a low-current output using a low-cost NPN transistor. The
MAX8513's second regulator can be used to generate
0.8V to 27V output with a low-cost PNP transistor. Both
LDO regulators can operate either from the DC-DC controller
output or from a higher voltage derived with a flyback
overwinding on the DC-DC converter inductor. The
MAX8514's second LDO regulator is designed to provide
a negative output with an NPN transistor.
A sequence input allows the outputs to either power up
together, or for the DC-DC regulator to power up first
and each LDO controller to power up in sequence. An
input power-fail output (PFO-bar) is provided for input
power-fail warning, such as in dying-gasp applications.
A power-on reset circuit with a 140ms delay is also
included to indicate when all outputs have achieved
regulation and stabilized.
Key Features
Applications/Uses
Low-Cost DC-DC Controller with Two LDOs
Wide Input Range: 4.5V to 28V
300kHz to 1.4MHz Adjustable Switching Frequency
Low Noise for High Data-Rate xDSL Applications
Synchronizable to External Clock
Adjustable Soft-Start
Lossless Adjustable Foldback Current Limit
Power-On Reset with 140ms Delay
Adjustable Input Power-Fail Warning for Dying Gasp
Selectable Output-Voltage Sequencing or Output-Voltage Tracking
Notes: **This pricing is BUDGETARY, for comparing similar parts. Prices are in
U.S. dollars and subject to change. Quantity pricing may vary
substantially and international prices may differ due to local
duties, taxes, fees, and exchange rates. For volume-specific prices
and delivery, please see the price and availability page
or contact an authorized distributor.
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