PD-97563B
SBB SERIES
HIGH RELIABILITY CLASS K HYBRID,
RADIATION HARDENED, NON-ISOLATED
POINT OF LOAD (POL) VOLTAGE REGULATOR
Description
The SBB Series point of load (POL) DC to DC voltage
regulators are high reliability hermetically sealed thick
film hybrids designed to provide a single regulated DC
output from a DC voltage source. The output power
rating is 14W to 30W depending on output voltage,
with maximum current rating of 14A. The POLs are class
K qualified per MIL-PRF-38534. These products are
designed to operate continuously on board a space
craft up to the rated power output without power derating
for case temperature of 85°C. The POLs are suitable
for harsh radiation environments normally encountered
in the geo-synchronous orbit (GEO), medium earth orbit
(MEO), low earth orbit (LEO), deep space, and for other
challenging radiation design applications.
The SBB POL is a non isolated synchronous buck
regulator. It incorporates IR’s heritage- rich components
and circuit design library for long term reliability
expected of system designs with a mission life of up to
18 years or more. The SBB Series of POLs operate from
a DC input power source with the voltage range of 4.5V
to 5.5V. It converts DC input voltage down to a fixed and
highly stable DC output. The standard voltage outputs
are 1.0V, 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V. The output
is adjustable with the addition of an external resistor.
The output adjustment range is approximately ±10% of
a nominal output voltage. Also included is remote
sensing capability to compensate for voltage drops in
the output lines. This feature, in combination with the
output adjustment capability, enables an output voltage
of a POL to be accurately set as needed.
With its excellent efficiency performance, SBB POLs
are ideal as the point of load regulators for the
distributed power architecture (DPA) design systems.
Other key benefits include excellent dynamic load
response, precise voltage setting, remote output voltage
sensing and synchronization.
Single Output
Features
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Total dose >100K Rads (Si)
SEE hardness rated with LET > 82 MeV-cm
2
/mg
Operates from 4.5V to 5.5V DC supply
Fixed output voltage: 1V, 1.2V, 1.5V, 1.8V,
2.5V and 3.3V are standards
Output power up to 30W or 14A maximum
without de-rating
High efficiency to 89%
Remote sense compensation
Fixed 400 KHz operating frequency
Output adjustable to ±10% of nominal
output with an external resistor
Enable function pin for remote on/off control
Input undervoltage and output under
voltage protection
Overload and short circuit protection
Low noise with integrated input
and output filters
No external filter capacitors required
Soft start
Under voltage lockout (UVLO)
Synchronization
Output Status Telemetry(POK)
-55 to +85°C operating case temperature
without output power derating
MIL-PRF-38534 element evaluated components
Custom versions available
Derating per MIL-STD-1547 for space flight
MTBF > 2.8 million hours for space
flight environments
Standard Microcircuit Drawings (SMDs) Available
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1
11/28/12
SBB SERIES
Single Output
The product’s package footprint is less than three
square inches. The package and lid materials are
cold rolled steel. The low profile package measures
1.9"L x 1.5"W x 0.335"H, excluding mounting tabs
and input/output (I/O) pins. The ceramic sealed I/O
pins protrude the package’s side walls with the
mounting tabs on the corners of the side walls. The
I/O pins are copper Alloy 52. The pins are gold plated
for long term storage. Gold is to be removed prior to
assembly. A complete POL weighs less than 60
grams. Cooling of this device can be accomplished
by bonding the base of the package to a metal plate
or heat sink with a thermally conductive material.
The package’s mechanical outline and I/O pins
functional assignment are included in this data sheet.
The SBB POLs are designed, manufactured, tested,
and qualified at IR’s facility in San Jose, California
which is qualified to ISO9001 and MIL-PRF-38534
by DSCC. Flight hardware is 100% screened and
fully compliant to class K per MIL-PRF-38534.
Abbreviated screening version or engineering model
(EM) of the SBB is available for engineering evaluation.
Please refer to the Device Screening table for details.
Undervoltage Lockout (UVLO):
An UVLO circuit
prohibits the POL from operating when the line
voltage is too low to maintain the output voltage.
The POL will not start until the line input voltage
rises to approximately 4.3 volts and will shut down
when the input voltage drops below 3.9 volts.
Output Voltage Adjustment:
The output voltage
(Vout) of an SBB can be adjusted to ±10% of a
nominal output voltage. One external resistor with
a power rating of > 0.125 watt is required for this
function.
Following is the formula to determine an approximate
value of the resistor and how it needs to be
connected to the functional pins for a higher and a
lower output voltage with respect to the nominal
output voltage.
To reduce Vout, connect an adjust resistor to
Vadjust pin and Output pin
Circuit Description
The SBB Series POLs utilize a non-isolated buck
circuit design topology with synchronous output
rectification to maximize efficiency. The nominal
switching frequency is 400 KHz. An internal EMI filter
minimizes the reflected switching ripple current to
meet most space applications at the system level. A
two-stage output filter reduces the output ripple and
noise to a very low level required by today’s digital
loads. No external filter capacitors are required for
typical design applications.
Output current is limited under any load fault
condition. It is designed to behave similar to a
constant current source with the output voltage
dropping below nominal. The SBB POL will resume
normal operation when the load current is reduced
below the current limit point. This protects the POL
from both overload and short circuit conditions.
The current limit threshold exhibits a negative
temperature coefficient to reduce the possibility of
thermal runaway.
⎧
11280
×
Vout
⎫
−
10280
⎪
⎪
⎪
⎪
Vnom
Radj
= ⎨
⎬
2
×
Vout
⎪
⎪
2
−
⎪
⎪
Vnom
⎩
⎭
To increase Vout, connect an adjust resistor to
Vadjust pin and Output Return pin
⎧
9280
×
Vout
⎫
−
10280
⎪
⎪
Vnom
⎪
⎪
Radj
= ⎨
⎬
2
×
Vout
⎪
⎪
2
−
⎪
⎪
Vnom
⎩
⎭
Where:
Radjust is the value of the adjust resistor in Ohms(Ω)
Vnom is the nominal output voltage of the SBB
2
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SBB SERIES
Single Output
Remote Sense:
Output pins 4 and 5 must be connected
to +Sense pin 6 for proper operation. The +Sense pin
may be connected remotely to the output line at the
load to compensate for a voltage drop in the output line
for precise optimum output regulation. The maximum
voltage compensation in combination with the output
voltage adjustment (if required) is limited to 10% of the
nominal output voltage.To enhance the load regulation
performance Input Return (Pin 2) may be connected
externally to Output Return (Pin 3).
Enable:
An Enable pin is provided to remotely turn
the POL on or off. It can also be used for output
sequenceing for multiple SBB POL regulators. The
nominal threshold relative to the input return (pin 2)
is 2.5V. If 3.9 volts or greater are applied to the
Inhibit pin (pin 3) then the POL will operate normally.
The pin may be left open for normal operation. A
voltage of 0.4V or less will cause the SBB POL to
shut down.
Synchronization:
An external synchronization port
is provided to allow the multiple SBB POLs to be
synchronized to an external frequency source to
minimize the noise interference coming from the
switching operation of the POLs. The synchronization
frequency ranges from 360 KHz to 440 KHz and the
synchronization signal port can be driven from 5V
logic.
POK:The
SBB POL also provides a power ok (POK)
output status signal at Pin 11. A logic high signal is
present when the POL’s output voltage is greater
than 95% of the nominal output voltage. A logic low
signal at Pin 11 indicates the POL’s output voltage
drops below the output voltage threshold of 95%
The SBB Series POLs use a proven conservative
design methodology with careful incorporation of
known radiation performance devices and established
reliability components. All components are fully
derated to MIL-STD-1547. Standard design analyses
include stress, thermal, failure modes and effects
(FMEA), reliability & worst case and are available
upon request.
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3
SBB SERIES
Single Output
Absolute Maximum Ratings
Input voltage range
Output power
Lead temperature
Operating case temperature
Storage temperature
-0.5Vdc to +7.0Vdc
Internally limited
300°C for 10 seconds
-55°C to +125°C
-55°C to +125°C
1
Recommended Operating Conditions
Input voltage range
Output power
1
4.5Vdc to 5.5Vdc
0 to Max. Rated
-55°C to +85°C
-55°C to +125°C
Operating case temperature
Storage temperature
Meets derating per MIL-STD-1547
Electrical Performance Characteristics
Parameter
Group A
Subgroup
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 5.0V DC ± 5%, C
L
= 0
unless otherwise specified
Limits
Unit
Min
4.5
1
1
1
1
1
1
2,3
2,3
2,3
2,3
2,3
2,3
0.985
1.182
1.478
1.773
2.463
3.251
0.970
1.164
1.462
1.755
2.450
3.234
Nom
5.0
Max
5.5
1.015
1.218
1.523
1.827
2.538
3.350
1.030
1.236
1.537
1.855
2.550
3.366
14
16.8
21
25.2
30
30
0
0
0
0
0
0
-0.25
14
14
14
14
12
9.1
0.25
V
V
Input Voltage
Output Voltage (V
OUT
)
SBB501S
SBB501R2S
SBB501R5S
SBB501R8S
SBB502R5S
SBB503R3S
SBB501S
SBB501R2S
SBB501R5S
SBB501R8S
SBB502R5S
SBB503R3S
Output power (P
OUT
)
SBB501S
SBB501R2S
SBB501R5S
SBB501R8S
SBB502R5S
SBB503R3S
Output current (I
OUT
)
SBB501S
SBB501R2S
SBB501R5S
SBB501R8S
SBB502R5S
SBB503R3S
Line regulation (VR
LINE
)
Load regulation (VR
LOAD
)
SBB501S
SBB501R2S
SBB501R5S
SBB501R8S
SBB502R5S
SBB503R3S
Switching frequency (F
S
)
I
OUT
= 100% rated load
I
OUT
= 100% rated load
1.000
1.200
1.500
1.800
2.500
3.300
1,2,3
V
IN
= 4.5, 5.0 and 5.5V, Note 2
W
1,2,3
V
IN
= 4.5, 5.0 and 5.5V, Note 2
A
1,2,3
V
IN
= 4.5, 5.0, 5.5 Volts
I
OUT
= 0, 50%, 100% rated
V
IN
= 4.5, 5.0, 5.5 Volts
I
OUT
= 0, 50%, 100% rated
%
1,2,3
-15
-15
-15
-15
-13
-17
360
400
15
15
15
15
17
17
440
mV
1,2,3
Sync Input (Pin 9) open
KHz
For Notes to Electrical Performance Characteristics Table, refer to page 6
4
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SBB SERIES
Single Output
Electrical Performance Characteristics
Parameter
Input current (I
IN
)
SBB501S
SBB501R2S
SBB501R5S
SBB501R8S
SBB502R5S
SBB503R3S
Output ripple (V
RIP
)
SBB501S
SBB501R2S
SBB501R5S
SBB501R8S
SBB502R5S
SBB503R3S
Efficiency (E
FF
)
SBB501S
SBB501R2S
SBB501R5S
SBB501R8S
SBB502R5S
SBB503R3S
Enable Input (Inhibit Function)
Open circuit voltage
Drive current (sink)
Voltage range
Synchronization Input
Frequency range
Pulse high level
Pulse low level
Pulse transition time
Pulse duty cycle
Current Limit point
SBB501S
SBB501R2S
SBB501R5S
SBB501R8S
SBB502R5S
SBB503R3S
Power dissipation, load fault (P
D
)
SBB501S
SBB501R2S
SBB501R5S
SBB501R8S
SBB502R5S
SBB503R3S
Output response to
Step load changes (V
TLD
)
SBB501S
SBB501R2S
SBB501R5S
SBB501R8S
SBB502R5S
SBB503R3S
Group A
Subgroup
( continued )
Limits
Unit
Min
Nom
130
Max
200
mA
Conditions
-55°C
≤
T
C
≤
+85°C
V
IN
= 5.0V DC ± 5%, C
L
= 0
unless otherwise specified
I
OUT
= 0, Pin 10 open
Pin 10 shorted to pin 2
40
50
1,2,3
V
IN
= 4.5, 5.0, 5.5 Volts
I
OUT
= 100% rated load,
Note 3
30
30
30
30
25
20
67
70
73
76
82
86
V
IN
- 0.8
-0.5
360
Vin -0.5
-0.5
20
14.5
14.5
14.5
14.5
12.5
9.5
V
IN
500
50
440
Vin +0.5
+0.5
50
80
21.5
21.5
21.5
21.5
17.9
13.7
11
11
11
11
9.5
8.0
mV p-p
1,2,3
I
OUT
= 100% rated load
%
1,2,3
Note 1
V
µA
V
KHz
V
V
nS
%
1,2,3
External clock for Sync Input (Pin 9)
Note 1
1,2,3
V
OUT
= 90% of Nominal
A
1,2,3
Short Circuit, Overload, Note 5
W
4,5,6
Half Load to/from Full Load, Note 6
-150
-150
-150
-150
-200
-200
150
150
150
150
200
200
mV
For Notes to Electrical Performance Characteristics Table, refer to page 6
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