MAX20002CATPASLASHV+ datasheet(13/19 Pages) MAXIM

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A logic-low at EN shuts down the device. During shut-

down, the internal linear regulator and gate drivers turn

off. Shutdown is the lowest power state and reduces the

quiescent current to 5µA (typ). Drive EN high to bring the

devices out of shutdown.

Spread-Spectrum Option

The spread spectrum can be enabled on the device

using a pin. When the SPS pin is pulled high the spread

spectrum is enabled and the operating frequency is varied

±3% centered on FOSC. The modulation signal is a trian-

gular wave with a period of 110μs at 2.2MHz. Therefore,

FOSC ramps down 3% and back to 2.2MHz in 110μs and

also ramps up 3% and back to 2.2MHz in 110μs. The

cycle repeats.

For operations at FOSC values other than 2.2MHz, the

modulation signal scales proportionally (e.g., at 400kHz,

the 110μs modulation period increases to 110μs x

2.2MHz/0.4MHz = 550μs).

The internal spread spectrum is disabled if the devices

are synchronized to an external clock. However, the

devices do not filter the input clock on the FSYNC pin and

pass any modulation (including spread spectrum) present

on the driving external clock.

Internal Oscillator (FOSC)

The switching frequency (fSW) is set by a resistor (RFOSC)

connected from FOSC to AGND. For example, a 400kHz

switching frequency is set with RFOSC = 73.2kΩ. Higher

frequencies allow designs with lower inductor values and

less output capacitance. Consequently, peak currents and

I2R losses are lower at higher switching frequencies, but

core losses, gate-charge currents, and switching losses

increase.

Overtemperature Protection

Thermal overload protection limits the total power

dissipation in the device. When the junction temperature

exceeds 175°C (typ), an internal thermal sensor shuts

down the internal bias regulator and the step-down

converter, allowing the IC to cool. The thermal sensor

turns on the IC again after the junction temperature cools

by 15°C.

Overvoltage Protection (OVP)

If the output voltage reaches the OVP threshold, the

high-side switch is forced off and the low-side switch is

forced on until the negative-current limit is reached. After

negative-current limit is reached, both the high-side and

low-side switches are turned off. The MAX20002C/E and

MAX20003C/E feature an additional clamp and lower

OVP threshold to limit the output-voltage overshoot for

automotive conditions. Contact the Maxim Applications

team to determine if the MAX20002C/E or MAX20003C/E

are needed for your application.

Applications Information

Setting the Output Voltage

Connect FB to BIAS for a fixed +5V/3.3V output voltage.

To set the output to other voltages between 1V and 10V,

connect a resistive divider from output (OUT) to FB to

AGND (Figure 2). Select RFB2 (FB to AGND resistor)

less than or equal to 500kΩ. Calculate RFB1 (OUT to FB

resistor) with the following equation:

OUT

FB1

FB2

-1





















where VFB = 1V (see the Electrical Characteristics

table).

Forced-PWM and Skip Modes

In PWM mode of operation, the devices switch at

a constant frequency with variable on-time. In skip

mode of operation, the converter’s switching frequency

is load dependent. At higher load current, the switching

frequency does not change and the operating mode is

similar to the PWM mode. Skip mode helps improve

efficiency in light-load applications by allowing the

converters to turn on the high-side switch only when the

output voltage falls below a set threshold. As such, the

converters do not switch MOSFETs on and off as often

as in the PWM mode. Consequently, the gate charge and

switching losses are much lower in skip mode.

Figure 2. Adjustable Output-Voltage Setting

RFB1

RFB2

VOUT

MAX20002

MAX20003

www.maximintegrated.com

Maxim Integrated │ 13

MAX20002/MAX20003

36V, 220kHz to 2.2MHz, 2A/3A Fully

Integrated Step-Down Converters

with 15μA Operating Current

MAX20002CATPA/V+ Datasheet(PDF) 13 Page - Maxim Integrated Products

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