SANYO STK730C Datasheet

Thick Film Hybrid IC

Ordering number : EN4472A

73096HA (OT)/82793YO 5-2862 No. 4472-1/6

SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters

TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN

5 V Single Output MOS Chopper Regulator

STK730C

Overview

The STK730C is a chopper type step-down dedicated
5 V single output regulator that uses a power MOSFET
as its switching element and a Schottky barrier diode
(SBD) as its flywheel diode.

The STK730C covers the 2 A and higher current
regions, regions that are difficult to handle with three
terminal step-down regulators. As compared with earlier
chopper regulator products that used bipolar transistors,
the efficiency of the STK730C has been further
improved by the adoption of MOSFET and SBD
technologies, and use of the STK730C enables further
miniaturization and increased performance in the end
product since it corresponds to the adoption of a
dedicated switching controller IC. Furthermore, due to
the development of a unique MOS drive circuit, the
STK730C can be used with a single power supply input.

The STK730C can prove useful when standardizing and
rationalizing power supply circuit design, since it can
handle a wide range of power supply circuits in a
number of applications, either as the secondary side
regulator in a switching power supply or as the output
regulator following AC transformer rectification.

Applications

• Power supplies in printers and other office equipment

• Power supplies in robots and other factory automation
related equipment

• Power supplies in VCRs and other consumer products

• Secondary side regulators in switching power supplies

Features

• IMST substrate (insulated metal substrate technology)

• Efficiency improved (by 10%) by the adoption of
MOSFET and SBD technology.

• An auxiliary drive power supply is no longer required
due to the development of a unique NMOS FET drive
circuit. This means that the STK730C can be used
with a single power supply, thus allowing
simplification of the input system.

• Built-in reverse going linear overload characteristic
curve overcurrent protection circuit

• Ground line handling is eased even in multi-output
power supply structures due to placement of the
overcurrent detection resistor on the plus line.

• The STK730C’s separate excitation oscillator
structure provides high stability in the switching
frequency.

• The STK730C’s switching operating frequency is set
at 125 kHz, which minimizes beating when used in a
multiple output structure with STK731 and STK733
type products.

Package Dimensions

unit: mm

4141

[STK730C]

STK730C

Specifications

Maximum Ratings at Ta = 25°C

Parameter Symbol Rating Unit
Maximum DC input voltage Vin (DC) max 40 V
Maximum output current I

O

max 5 A

Thermal resistance

θj-c 3.5 (SBD 7.2) °C/W
Junction temperature Tj max 150 (SBD 125) °C
Operating case temperature Tc max 105 °C
Storage temperature T

stg

–30 to +105 °C

Electrical Characteristics at Ta = 25°C, for the specified test circuit

Rating

Parameter Symbol Condition

min typ max

Unit

Output voltage setting V

O

Vin (DC) = 24 V, IO= 1 A

4.95 5.05 5.15 V

Ripple voltage V

rp

10 mVrms

Input regulation Reg-IN Vin (DC) = 10 to 40 V, I

O

= 1 A 10 mV/V

Load regulation Reg-L Vin (DC) = 24 V, I

O

= 0.5 to 5 A 30 mV/A

Overcurrent protection start current I

ocp

Vin (DC) = 24 V 5 A

Efficiency η Vin (DC) = 24 V, I

O

= 2.5 A 80 %

Operating frequency f

Vin (DC) = 24 V, I

O

= 1 A

125 kHz

Output voltage temperature coefficient T

cvo

0.02 %/°C

Block Diagram

No. 4472-2/6