1

2.5A Regulator with Integrated High-Side MOSFET for

Synchronous Buck or Boost Buck Converter

ISL78200

The ISL78200 is a synchronous buck controller with a 90mΩ

high side MOSFET and low side driver integrated. The ISL78200

supports a wide input voltage range from 3V to 40V. Regarding

the output current capability, the ISL78200 can typically support

range of 8V to 36V, 500kHz, +85°C ambient temperature with

still air. For any specific application, the actual maximum output

current depends upon the die temperature not exceeding

+125°C with the power dissipated in the IC, which is related to

input voltage, output voltage, duty cycle, switching frequency,

ambient temperature and board layout, etc. Refer to the Output

Current section on page 14 for more details.

The ISL78200 has flexible selection of operation modes of

forced PWM mode and PFM mode. In PFM mode, the

quiescent input current is as low as 300µA and can be further

and PWM can be programmed to cover wide applications.

The low side driver can be either used to drive an external low

side MOSFET for a synchronous buck, or left unused for a

standard non-synchronous buck. The low side driver can also

be used to drive a boost converter as a pre-regulator that

greatly expands the operating input voltage range down to 3V

or lower (refer to “Typical Application Schematic III - Boost

Buck Converters” on page 5).

The ISL78200 offers the most robust current protections. It

uses peak current mode control with cycle-by-cycle current

limiting. It is implemented with frequency foldback under

current limit condition; in addition, the hiccup overcurrent

mode is also implemented to guarantee reliable operations

under harsh short conditions.

The ISL78200 has comprehensive protections against various faults

including overvoltage and over-temperature protections, etc.

Features

• Ultra Wide Input Voltage Range 3V to 40V

• Selectable Mode Operation

- Forced PWM Mode

-PFM Mode

- Programmable Current Boundary between PFM and PWM

Modes

• 300µA IC Quiescent Current (PFM, No Load); 180µA Input

• Less than 3µA Standby Input Current (IC Disabled)

• Operational Topologies

-Synchronous Buck

-Non-Synchronous Buck

-Two Stage Boost Buck

• Programmable Frequency from 200kHz - 2.2MHz and

Frequency Synchronization Capability

• Reliable Cycle by Cycle Overcurrent Protection

- Temperature Compensated Current Sense

- Frequency Foldback

- Programmable OC Limit

-Hiccup Mode Protection in Worst Case Short Condition

• 20 Ld HTSSOP Package

• Pb-Free (RoHS Compliant)

Applications

• Automotive Applications

• General Purpose Power Regulator

• 24V Bus Power

•Battery Power

• Embedded Processor and I/O Supplies

FIGURE 1. TYPICAL APPLICATION

FIGURE 2. EFFICIENCY, SYNCHRONOUS BUCK, PFM MODE,

VOUT

ISL78200

VCC

SGND

MODE

BOOT

VIN

PHASE

PGND

FS

EXT_BOOST

EN

FB

COMP

VIN

AUXVCC

LGATE

ILIMIT

SS

SYNC

PGOOD

50

55

60

65

70

75

80

85

90

95

100

0.1m

1m

10m

100m

1

2.5

LOAD CURRENT (A)

September 22, 2011

FN7641.0

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

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