PD-94473
Low Dropout
Linear Regulator
Hermetic Package
Product Summary
Part Number
OM8508SC
OM8508SF
Dropout
5.0 V
5.0 V
I
O
3.3A
3.3A
Vin
Package
3.0V
MO-078AA
3.0V 8-lead Flatpack
OM8508SC
OM8508SF
+5.0Vin to +3.3Vout at 3.0A
MO-078AA
Features:
The OM8508 is a low dropout linear regulator designed
specifically for space applications. Housed in either a 5
pin through hole or 8 lead surface mount package, these
regulators provide high reliability in military/defense ap-
plications. The low dropout voltage of 0.4V @ 3A makes
the part particularly useful for applications requiring low
noise and higher efficiency.
Ultra low dropout voltage of 0.4 volt
significantly reduces power consumption
Low noise, higher efficiency
Remote shutdown permits power
sequencing to be easily implemented
Hermetic MO-078AA (TO-258AA) and 8-
lead flat pack ensure higher reliability
Available H-level screened
Absolute Maximum Ratings
Symbol
Io
Vin
P
TOT
RTHJC
R
THJC
TJ
TSTG
T
L
Parameter
Output Current
Input Voltage
Power Dissipation TC=25
o
C
Thermal Resistance, Junction to Case (MO-078AA)
Thermal Resistance, Junction to Case (8-lead flatpack)
Operating Junction
Storage Temperature Range
Lead Temperature
Value
3.5
+7.0
19
6.5
6.5
-55 to +125
-65 to +150
300
Units
A
V
W
W/°C
W/°C
o
o
o
C
C
C
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1
6/6/02
OM8508SC, OM8508SF
Electrical Characteristics
@ T
A
= 25°C (Unless Otherwise Specified)
Parameter
Ou tp u t Vo ltag e
In p u t Vo ltag e Ran g e-
Lin e Reg u latio n
Lo ad Reg u latio n
Cu rren t Limit
Rip p le Rejectio n
Sh u td o wn So u rce Cu rren t
Sh u td o wn Pin Th res h o ld
Ou tp u t Vo ltag e at
Sh u td o wn
Co n d itio n s
Vin = 5.0V, Io = 3.0A
Io = 3.0A
4.75
≤
Vin
≤
5.25, Io = 3.0A
4.5
≤
Vin
≤
5.5, Io = 50mA
Vin = 5.0V
10ma
≤
Io u t
≤
3.0A
Vin = 5.0V, Ov ercu rren t
Latch u p
F= 120 Hz., Vo u t= Vref
Vs h d n = 5V
Is o u rce= 200u A
Vin = 5.0, Io = 50mA ,
Sh d n = +5.0V
Sy mb o l
Vo u t
Vlin e
Vlo ad
Ilatch
M in .
3.267
4.5
-100
-5
-20
3.0
65
Is h d n
Vs h d n
Vo u t
(s h d n )
200
1.0
-0.1
1.6
0.1
Ty p .
3.3
M ax
3.333
5.5
+100
+5
+20
Un it
V
V
mV
mV
mV
A
dB
uA
V
V
Electrical Characteristics
T
A
= -55 to +125°C
Parameter
Output Voltage
Input Voltage Range-
Operating
Line Regulation
Load Regulation
Current Limit
Ripple Rejection
Shutdown Source Current
Shutdown Pin Threshold
Output Voltage at
Shutdown
Conditions
Vin= 5.0V, Io= 3.0A
Io= 3.0A
4.75
≤
Vin
≤
5.25, Io= 3.0A
4.5
≤
Vin
≤
5.5, Io= 50mA
Vin= 5.0V3V
10ma
≤
Iout
≤
3.0A
Vin= 5.0V, Overcurrent
Latchup
F= 120 Hz., Vout= Vref
Vshdn= 5V
Isource= 200uA
Vin= 5.0V, Io= 50mA,
Shdn= +5.0V
Symbol
Vout
Min.
3.135
4.5
-150
-150
-150
3.0
65
Ishdn
Vshdn
Vout
(shdn)
200
1.0
-0.1
1.6
0.1
Typ.
3.3
Max
3.465
6.5
+150
+150
+150
Unit
V
V
mV
mV
mV
A
dB
uA
V
V
Vline
Vload
Ilatch
Simplified Schematic
V in
D rive
V out
S hutdown
G nd
G round
2
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OM8508SC, OM8508SF
OM8508 Ripple Rejection vs. Frequency
120
100
80
(db)
60
40
20
0
100
1,000
10,000
100,000
1,000,000
Frequency (hZ)
3A
1.5A
.75A
.50A
V in
V in
Vout
Vout
O M 8508
100uF 16V
T a n ta lu m
SHDN
GND
1 .0 u F
C e ra m ic
X7R
2 2 0 u F 6 .3 V
T a n ta lu m
G ro u n d
Vout = Vref x (1+R1/1000)
In order to maintain regulation and stability specified additional input and output bulk capacitors are
recommended. Capacitors recommended above should be low ESR tantalums with tolerances of +/-
20% max. Internal to the product are a 4.7uF input capacitor and a 4.7uF output capacitor in parallel with a
0.33uF ceramic capacitor.
Shutdown:
The regulator can be shutdown by applying a voltage >1.6V to pin 4. The regulator will restart
when the SHDN pin is pulled below the shutdown threshold of 1.0V. If remote shutdown is not required,
pin 4 shold be connected to GND to insure a safe “off” state.
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OM8508SC, OM8508SF
Mechanical Outline MO-078AA
Base:
GLIDCOP
Pins:
Copper core, Alloy 52
Seals:
Glass
Pin Connections
Terminal
Description
1
Vin
2
GND
3
Vout
4
Shutdown
5
No Connection
Base
1 2 3 4 5
Mechanical Outline 8-Lead Flat Pack
Base:
1010-1018 C.R.S.
Pins:
#52 Alloy, Copper Cored
Seals:
Glass – 9013 or Equiv.
Finish:
100-250 Microinches
Electroless Nickel Over 50-250
Microinches Electrolytic Nickel.
Pin Connections
Terminal
Description
1,2
GND
3
Shutdown
4
No Connection
5,6
Vout
7,8
Vin
0 .7 5 5
0 .7 4 5
0 .7 5 5
0 .7 4 5
8X
0 .0 8 0
0 .0 7 0
8 7 6 5
1 2 3 4
0 .1 1 0
8x
0 .1 5 0
0 .1 0 5
0 .2 2 5
0 .3 0 5
0 .2 9 5
0 .0 9 5
0 .1 8 0
0 .1 6 5
0 .0 4 0
0 .0 6 5
0 .0 4 0
0 .0 6 5
8 X 0 .0 2 0
0 .0 1 6
4
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OM8508SC, OM8508SF
Part Number Nomenclature
OM
Omnirel
8508
Device
X
X
X
Screening
S=Isolated Package
N=Non-Isolated
Pa rt Num be r
OM8508SCP
OM8508SCH
OM8508SFP
OM8508SFH
Pa cka ge De scription
MO-078AA 5 - Lead
MO-078AA 5 - Lead
8 -Lead Flat Pack
8 -Lead Flat Pack
Scre e ning
100% Final Electrical
Class H per MIL-PRF-38534
100% Final Electrical
Class H per MIL-PRF-38534
MIL-PRF-38534 Screening Requirements
TEST/INSPECTION
SCREENING LEVEL MIL-STD-883
Class H
Method
Pre Seal Burn-In
Nondestructive Bond Pull
Internal Visual
Temperature Cycle
Constant Acceleration
Mechanical Shock
PIND
Pre Burn-In Electrical
Burn-In
Final Electrical
Seal
Radiographic
External Visual
Optional
N/A
100%
100%
100%
100%
N/A
Optional
100%
100%
100%
N/A
100%
1030
2023
2017
1010
2001
2002
2020
1015
1014
2012
2009
WORLD HEADQUARTERS:
233 Kansas St., El Segundo, California 90245, Tel: (310) 2527105
IR LEOMINSTER:
205 Crawford St., Leominster, Massachusetts 01453, Tel: (978) 5345776
Data and specifications subject to change without notice.
6/2002
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