MSK QCH28512T, QCH28512TE, QCH28512TH, QCH28512TK, RCH28512T Datasheet

DESCRIPTION

The QCH28512T/RCH28512T series of DC-DC convert­ers provides the ruggedness, reliability and features re­quired to meet the advanced challenges of today's hi-rel
market. This family of converters uses all surface-mounted
hybrid components including magnetics, all ceramic capaci­tors and ultrasonic wirebonds to give long life in full tempera­ture range and high acceleration environments. There is no
power derating anywhere in the –55°C to 125°C operating
range.

This product family is tolerant of many types of faults
including load short, load overload, loss of voltage feedback,
large forward and reverse voltages applied to the synchroniza­tion pin and input overvoltage. This converter family will
operate during input transients to 80 volts. The output voltages
have little overshoot during the input voltage transient such
that typical logic and linear parts on the outputs will stay well
within data sheet absolute maximums.

Other operational features include low duty factor current
limit and dynamic current limit threshold. The current limit
operates in a cyclic on-off mode with an on time of about 2
milliseconds and an off time of 20 milliseconds for a duty factor
of about 10 percent. This limits the converter dissipation to
about 1 watt, so there is no danger of overheating during an
output fault at 125° C. The dynamic current limit threshold

allows over 50 percent more current to flow for a short time
after power application, release from shutdown or recovery
from previous current limit allowing large load capacitances to
be charged during turn-on.

This converter family is a push-pull 400 kHz forward con­verter with full isolation between the input side, output side and
case. This isolation is achieved without optocouplers for an
even greater margin of reliability. The converter is housed in
a power DIP package and is hermetically sealed. The
RCH28512T has tabs for bolting the device down.

EXTERNAL CONNECTIONS

BLOCK DIAGRAM

HI-REL DESIGN

 REPLACES APEX DT28512T/F

 WAVE SOLDERABLE PACKAGE

 ALL CERAMIC CAPACITORS

 NO OPTOCOUPLERS

 SURFACE MOUNT MAGNETICS

 WITHSTANDS 3000 G Y1 AXIS

 OVER-VOLTAGE PROTECTION (OVP) OPTION

OTHER FEATURES  TRIPLE OUTPUT

 NO DERATING  55°C TO +125°C

 WIDE SUPPLY RANGE  16 TO 40 VOLTS

 HIGH ISOLATION  500V

 HIGH POWER DENSITY  23 W/in

3

 REMOTE SHUTDOWN

 EXTERNAL SYNCH INPUT (FULLY TTL COMPAT-

IBLE OPTION)

4707 Dey Road Liverpool, N.Y. 13088

M.S.KENNEDY CORP.

[phone]

QCH28512T/

RCH28512T

ISO-9001 CERTIFIED BY DSCC

30W TRIPLE

DC-DC

CONVERTERS

PRELIMINARY Rev. - 6/01

1

QCH28512T

RCH28512T

1
2
3
4
5

POSITIVE INPUT
+5 OUT
OUT COMMON

-12 OUT
+12 OUT

10

9
8
7
6

INPUT COMMON
SYNCH
INHIBIT
CASE GND
CASE GND

SPECIFICATIONS

INPUT VOLTAGE V

IN

No load 1, 2, 3 0 28 50 Vdc Normal

to full load 16 40 Operating

1

50 80 Vpk Transient

UVLO V

UVLO

1, 2, 3 10 12.5 14 Vdc

INPUT CURRENT I

IN

NoLoad 1, 2, 3 0.12 Adc

Full load

2

1.25 1.57 1.65

Inhibited 0.0001 0.002 0.005

OUTPUT CURRENT

3

I

MAIN

1 4.00 6.00 Adc
2, 3

I

+AUX

1 0.42 0.83
2, 3

I

-AUX

1 -0.42 -0.83
2,3

OUTPUT VOLTAGE

2,4

V

MAIN

1 4.95 5.0 5.05 Vdc
2,3

V

+AUX

1 11.85 12.00 12.15
2, 3

V

-AUX

1 -11.85 -12.00 -12.15
2, 3

OVP

4

V

OVP

1 5.3 5.6 5.9 Vdc
2, 3 5.14 6.10

OUTPUT POWER P

OUT

P

MAIN

1, 2, 3 0 20 30 W

P±

AUX

01020

P

TOT

030

P

OVERLOAD

30 35 65

(5)

EFFICIENCY

2

η 163%

2, 3

LINE REGULATION VR

LINE

V

IN

1 5 10 mV Main

16-40V 2, 3 10 50

1 50 75 Aux
2, 3 120 150

LOAD REGULATION VR

LOAD

I

MAIN

1 5 20 mV Main

0↔4A 2, 3 20 50

±I

AUX

1 50 75 Aux

0↔0.42A 2, 3 150 250

INPUT VOLTAGE RANGE 0 to 50 VDC
INPUT VOLTAGE TRANSIENT RANGE 80V@50mS
OUTPUT WITHSTAND VOLTAGE 25 VDC
STORAGE TEMPERATURE –65 to +150°C
OPERATING TEMPERATURE –55 to +125°C
TEMPERATURE, pin soldering 10 seconds 300 °C MAX

ABSOLUTE MAXIMUM RATINGS

ABSOLUTE MAXIMUM RATINGS

SPECIFICATIONSQCH28512T/RCH28512T

TEST GROUP A

12

PARAMETER SYMBOL CONDITIONS SUBGROUP MIN TYPICAL MAX UNITS COMMENT

Unless noted: –55°C ≤ T

CASE

≤ 125°C, 16Vdc ≤ VIN ≤ 40Vdc, P

MAIN

= 20W, P+

AUX

= P-

AUX

= 5W.

2

PRELIMINARY Rev. - 6/01

CROSS REGULATION VR

CROSS

±I

AUX

1 5 20 mV Main

0↔0.42A 2, 3 20 50

I

MAIN

1 50 75 ±Aux

0↔4A 2, 3 150 250

CURRENT LIMIT I

LIM

1 115 125 %
2, 3

LOAD FAULT POWER P

D

Overload

6

1, 2, 3 14 25 W

Short Ckt. 6

INHIBIT PIN VOLTAGE

7

V

ENH

Enabled 1, 2, 3 12 16.8 V dc

V

ENL

Inhibited 0 5

INHIBIT PIN CURRENT

7

I

ENH

Enabled 1, 2, 3 0 10 µA dc

I

ENL

Inhibited 650 1200 1800

ISOLATION R

ISO

500V dc 1, 2, 3 100 Meg Ω Primary

to Secondary to Case

CAPACITIVE LOAD C

L

1, 2, 3 330 500 µF Main

10 22 ±Aux

INPUT CURRENT RIPPLE2I

RIP

4 100 mA rms
5, 6 120 250

OUTPUT VOLTAGE RIPPLE V

RIP

4 15 45 mV rms Main
5, 6 30 90
4 12 36 ±Aux
5 ,6 25 75

SWITCHING FREQUENCY F

SW

4, 5, 6 350 400 450 kHz

SYNC. FREQUENCY F

SYNC

4, 5, 6 300 650 kHz

SYNC. PIN VOLTAGE

8

V

HI

1, 2, 3 2.4 – V dc

V

LO

– 0.4

SYNC. PIN CURRENT I

SYN

H 1, 2, 3 -400 µA dc

I

SYN

L -500 -750

TURN ON TIME

9

T

ON

448mS

TURN ON OVERSHOOT VT

ON

CL=0 4 0 300 mVdc Main

4 900 ±Aux

STEP LOAD TRANSIENT, VT

LOADCL

=0, I

MAIN

=50↔100% 4 -800 +800 mVdc Main

RESPONSE CL=0, I

AUX

=50↔100% 4 500 750 ±Aux

SPECIFICATIONS

QCH28512T/RCH28512T

TEST GROUP A

12

PARAMETER SYMBOL CONDITIONS SUBGROUP MIN TYPICAL MAX UNITS COMMENT

Unless noted: –55°C ≤ T

CASE

≤ 125°C, 16Vdc ≤ VIN ≤ 40Vdc, P

MAIN

= 20W, P+

AUX

= P-

AUX

= 5W.

3

PRELIMINARY Rev. - 6/01