Ap p lic a tion Note
Re m ote ON/ OFF Control
De ra ting
The C HB75 se rie s a llo ws the use r to switc h the m o d ule o n a nd o ff e le c tro nic a lly with re m o te o n/ o ff fe a ture . The C HB75 se rie s
a re a va ila b le with "p o sitive lo g ic " o r "ne g a tive lo g ic " (o p tio n).
The o p e ra ting c a se te m p e ra ture ra ng e o f the C HB75 se rie s is -40˚C to +100˚C. Whe n o p e ra ting the C HB75 , p ro p e r d e ra ting
o r c o o ling is ne e d e d .
Log ic Ta b le
Fo llo wing is the d e ra ting c urve o f C HB75 witho ut he a t sink
ON/OFF (2)
Logic State
Negative Logic
Module on
Positive Logic
Module off
(PIN 2)
Logic Low -
HIGH SIGNAL HERE
DISABLE OUTPUT
Power Dissipated vs Ambient Temperature and Air Flow
Switch Closed
25
Natural Convection
20 ft./min. (0.1 m/s)
-VIN (4)
Logic High -
Switch Open
Module on
Module off
20
100 ft./min. (0.5 m/s)
15
200 ft./min. (1.0 m/s)
10
300 ft./min. (1.5 m/s)
Exte rna l Outp ut Trim m ing
5
400 ft./min. (2.0 m/s)
O utp ut m a y o p tio na lly b e e xte rna lly trim m e d
(±10%) with a fixe d re sisto r o r a n e xte rna l trim -
p o t a s sho wn.
0
+SENSE (8)
+SENSE (8)
60
40
70
80
90
0
100
50
10
20
30
TRIM DOWN
Ambient Temperature, Ta(Deg. C)
10K ohms
TRIMPOT
TRIM (7)
TRIM (7)
Fo rc e d C o nve c tio n Po we r De ra ting with No He a t Sink
TRIM UP
-SENSE (6)
-SENSE (6)
Whe re :
The p o we r d issip a tio n (Pd ):
Pd = Pi - Po = Po (1- ) /
The the rm a l re sista nc e a re list b e lo w:
Outp ut Noise
Cha rt o f The rm a l Re sista nc e vs Air Flo w:
The o utp ut no ise is m e a sure d with 10µF ta nta lum c a p a c ito r a nd 1.0µF c e ra m ic c a p a c ito r a c ro ss o utp ut.
AIR FLO W RATE
TYPIC AL Rc a
Na tura l C o nve c tio n
100 ft./ m in.
7.12 ˚C/ W
6.21 ˚C/ W
5.17 ˚C/ W
4.29 ˚C/ W
3.64 ˚C/ W
+Vout (9)
Ceramic
1.0µF
200 ft./ m in.
300 ft./ m in.
400 ft./ m in.
Resistor
Load
The te m p e ra ture rise ( T ):
To
Scope
Solid tantalum
T = Pd * Rc a
10µF
-Vout (5)
O utp ut No ise Te st C irc uit sc he m a tic
75
76
All Sp e c ific a tio n s Typ ic a l At No m in a l Lin e , Fu ll Lo a d a n d 25˚ C Un le ss O th e rw ise No te d .
RSG [ RSG ELECTRONIC COMPONENTS GMBH ]
