Allegro STRS6708, STRS6709, STRS6707 Datasheet

– WITH BIPOLAR SWITCHING TRANSISTOR

COLLECTOR

OVER-CURRENT

PROTECTION

ABSOLUTE MAXIMUM RATINGS

Supply Voltage, VIN........................... 15 V

Output Voltage, V

V

EBO

Continuous Output Current,

IC.......................................... See Table

1 ms Single-Pulse Output Current,

ICM........................................ See Table

Sink Current, IS......................... See Table

Drive Current, ID.......................... -700 mA

Feedback Current, I

Inhibit Voltage, V

Over-Current Protection Voltage Range,

V

OCP

Insulation Voltage,V

Package Power Diss., PD........ See Graph

Output Junction Temperature, TJ.. +150°C

Internal Frame Temperature, TF... +125°C

Operating Temperature Range,

TA............................... -20°C to +125°C

Storage Temperature Range,

T

stg

1

2

COMMON

BASE

SINK

DRIVE

FDBK

INHIBIT

3

4

5

6

7

8

V

9

IN

DRIVE

+

+

....................... 850 V

CEX

OSC.

FAULT

FAULT
LATCH

S

R

REF.

UVLO

Dwg. PK-001

................................................ 7 V

................. 20 mA

FDBK

........................... 15 V

INH

............................................ ±3.5 V

WM(RMS)

........... 2000 V

............................. -40°C to +125°C

STR-S6707 THRU

28113†

STR-S6709

OFF-LINE SWITCHING REGULATORS

The STR-S6707, STR-S6708, and STR-S6709 are specifically
designed to meet the requirement for increased integration and reliabil­ity in off-line quasi-resonant flyback converters. These devices incorpo­rate the primary control and proportional drive circuit with a third­generation high-voltage bipolar switching transistor.

Crucial system parameters such as maximum ON time and OFF
time are fixed during manufacture. Local control circuit decoupling and
layout are optimized within each device.

Cycle-by-cycle current limiting, under-voltage lock-out with hyster­esis, over-voltage protection, and thermal shutdown protect these
devices during all normal and overload conditions. Over-voltage
protection and thermal shutdown are latched after a short delay. A
versatile triple-level inhibit circuit includes the OFF time synchronization
required to establish quasi-resonant operation. The inhibit function has
also been expanded to initiate operation in stand-by mode in which the
power supply delivers a small fraction of the steady-state output power.
The dual requirements of dielectric isolation and low transient thermal
impedance and steady-state thermal resistance are satisfied in an over­molded single-in-line power package.

Proven in substantial volumes, these devices and their fixed­frequency counterparts represent a significant advance in off-line SMPS
reliability growth and integration.

FEATURES

■ Quasi-Resonant Operation for Low EMI and High Efficiency

■ Output Power to 220 W

■ Low-Power Output Standby Mode

■ Pulse-by-Pulse Over-Current Protection

■ Latched Over-Voltage and Thermal Protection

■ Third-Generation Switching Transistor with Proportional Drive

■ Maximum ON Time and Off Time Set During Manufacture

■ Internal Under-Voltage Lockout with Hysteresis

■ Over-Molded SIP with Integral Isolated Heat Spreader

Always order by complete part number:

Max. Cont. Peak Max. Sink

Part Number Current, I

C

STR-S6707 6 A 12 A 1.5 A
STR-S6708 7.5 A 15 A 1.5 A
STR-S6709 10 A 20 A 2 A

Current, I

CM

Current, I

S

Data Sheet

™

STR-S6707 THRU STR-S6709

OFF-LINE
QUASI-RESONANT FLYBACK
SWITCHING REGULATORS

STR-S6707 AND STR-S6708 FUNCTIONAL BLOCK DIAGRAM

FDBK

V

IN

9

UVLO

OVER-VOLT.

PROTECT

REF.

R

S

FAULT
LATCH

Q

TSD

OSC.

R

ton

+

INHIBIT

8

PROPORTIONAL

DRIVE

1 kΩ

0.7 Ω

DRIVE

5

SINK

4

3

BASE

1

COLLECTOR

0.75 V

7

3300 pF

R

toff

+

1.4 V

+

-1 V

2

COMMON

OVER-CURRENT

6

PROTECTION

+

5.1 V

Dwg. FK-001

ALLOWABLE PACKAGE POWER DISSIPATION MAXIMUM SAFE OPERATING AREA

30

60

54 W

40

20

3.2 W

ALLOWABLE PACKAGE POWER DISSIPATION in WATTS

0

20 60 100

MOUNTING SURFACE
TEMPERATURE

FREE AIR

RECOMMENDED MAX.
FRAME TEMP. = +100°C

TEMPERATURE in °C

LIMITED BY FRAME
TEMP. = +125°C MAX.

140

Dwg. GK-003-2

10

5.0

3.0

1.0

COLLECTOR CURRENT in AMPERES

0.5

0.3
0 200 400 600 1000

STR-S6709 (20 A)

STR-S6708 (15 A)

STR-S6707 (12 A)

L = 6 mH
I

B1

= 2.5 A (STR-S6707/08) or 3 A (STR-S6709)

I

B2

= 0.8 A (STR-SA6707/08) or 1.2 A (STR-S6709)

t

on

= 100 µs

dc < 1%

COLLECTOR-EMITTER VOLTAGE in VOLTS

800

Dwg. GK-002

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

Copyright © 1994 Allegro MicroSystems, Inc.

™

STR-S6707 THRU STR-S6709

OFF-LINE

QUASI-RESONANT FLYBACK

SWITCHING REGULATORS

STR-S6709

SINK

FUNCTIONAL BLOCK DIAGRAM

AS ABOVE

20 Ω

4

EXCEPT FOR SINK OUTPUT

ELECTRICAL CHARACTERISTICS at TA = +25°C, VIN = 8.5 V, voltage measurements are refer­enced to Common (pin 2) (unless otherwise noted).

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

On-State Voltage V
Under-Voltage Lockout V
Over-Voltage Threshold V
Output Leakage Current I
Output Saturation Voltage V

DC Current Gain h
Maximum ON Time t
Minimum OFF Time t
Over-Current Threshold V
Feedback Threshold Volt. V
Inhibit Threshold Voltage V

Latch Holding Current I
Latch Reset Voltage V
Supply Current I

Insulation RMS Voltage V

Thermal Shutdown T
Thermal Resistance R

INT

INQ

OVP(th)

CEX

CE(sat)

V

BE(sat)

FE

on

off

OCP(th)

FDBK(th)

INH(th)

INH

Q

IN(ON)

I

IN(OFF)

WM(RMS)

J

θJM

NOTES: Negative current is defined as coming out of (sourcing) the specified device terminal.

Typical Data is for design information only.

Turn-on, increasing V
Turn-off, decreasing V

IN

IN

7.6 8.0 8.4 V

4.6 4.9 5.2 V

9.2 – 10.7 V
VCE = 850 V, VBE = -1.5 V ––100 µA
STR-S6707, IC = 2 A, IB = 400 mA ––400 mV
STR-S6708, IC = 3 A, IB = 600 mA ––400 mV
STR-S6709, IC = 4 A, IB = 800 mA ––400 mV
STR-S6707, IC = 2 A, IB = 400 mA ––1.5 V
STR-S6708, IC = 3 A, IB = 600 mA ––1.5 V
STR-S6709, IC = 4 A, IB = 800 mA ––1.5 V
VCE = 4 V, IC = 1 A 29 – 61 –

33 – 41 µs
45 – 55 µs

-0.9 -1.0 -1.1 V
– 650 – mV

Oscillation stops 0.65 0.75 0.85 V
Oscillation synchronized – 1.4 2.0 V
Oscillation stops (fault latch set) 3.2 5.1 5.6 V
VIN reduced from 10.7 V to 4 V ––500 µA
IIN ≤ 100 µA, VIN reduced from 10.7 V 2.5 3.1 – V
Operating 15 – 29 mA

––200 µA

All terminals simultaneous reference 2000 –– V
metal plate against backside

125 150 – °C

Output junction to mounting surface – 2.0 – °C/W

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