VISHAY SI91860

Si91860
Vishay Siliconix
400-mA Smart Regulator for Network Interface Card
FEATURES
D
D
D
D
D
D
D
D
Single Fixed 3.3-V Output
Linear Regulator for Dual Power Inputs
Auxilliary Input Can Be Bypassed
Automatically Switches Between Linear Regulator
and Bypass Mode
Linear Regulator: 3.3-V "3% Output at 400-mA
Current
Linear Regulator: 600-mA Peak Output Current
Low Bypass Switch Drop: <55-mV Drop at 150 mA
Built-in Short Circuit and Thermal Shutdown
Protection
D Low Supply Current
D SOIC-8 Package
APPLICATIONS
D
D
D
D
Network Interface Cards (NIC)
PCMCIA Cards
Cardbus
Desktop Computers/Workstations
DESCRIPTION
The Si91860 provides a constant 3.3-V output with multiple
inputs. This function is required in many power interface
applications, such as the Network Interface Card (NIC). The
Si91860 is offered in small SOIC-8 package with up to 2-W
Power handling capability. The complete application circuit
uses only four external components.
The PCI Card has a 3.3-V Chipset while the PCI bus has two
independent 5-V sources. When needed, the two 5-V sources
are available from the PCI bus or directly from the
motherboard—normally 5 VIN and standby 5 VSB. The
internal regulator steps down from either of the 5-V supplies
to 3.3 V. A 200-mΩ power switch is integrated to connect the
3.3-VAUX input to the output. The power drawn priority is 5 VIN
> 5 VSB > 3.3 VAUX, where the selection is done internally and
automatically by the Si91860. The power handling capability
is as such as to carry at least 400-mA continuous load current
for any power input condition.
In order to satisfy the stringent ambient temperature
requirements in many applications, the Si91860 is rated for the
industrial temperature range of −40_C to 85_C.
The Si91860 is available in both standard and lead (Pb)-free
packages.
FUNCTIONAL BLOCK DIAGRAM
Si91860
5 VSB
5 VIN
Regulator
and
Control
3.3 VOUT
3.3 VAUX
GND
Document Number: 71340
S-40704—Rev. B, 19-Apr-04
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Si91860
Vishay Siliconix
ABSOLUTE MAXIMUM RATINGS
Pin 1, 2, 4 Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3 V to 6 V
Linear Regulator Output Current (peak) . . . . . . . . . . . . . . . . . . . . . . . . 600 mA
Bypass Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 600 mA
Maximum Junction Temperature, TJ(max) . . . . . . . . . . . . . . . . . . . . . . . . 150_C
Storage Temperature, TSTG . . . . . . . . . . . . . . . . . . . . . . . . . . −55_C to 150_C
ESD (Human Body Model) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 kV
Package Power Dissipationb
PD . . . . . . . . . . . . . . . . . . . . . . . . 2W (internally limited via thermal shutdown)
Thermal Impedance (JA)a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.5_C/W
Notes
a. Device mounted with all leads soldered or welded to PC board.
b. Derate 16 mW/_C above TA = 25_C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation
of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect device reliability.
RECOMMENDED OPERATING RANGE
5-VIN and 5-VSB Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 V to 5.5 V
Load Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 mA to 400 mA
3.3-VAUX Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 V to 3.6 V
Operating Ambient Temperature, TA . . . . . . . . . . . . . . . . . . . . −40_C to 85_C
SPECIFICATIONS
Test Conditions
Unless Otherwise Specified
Parameter
Symbol
Limits
−40 to 85_C
5 VIN = 5 VSB = 5 V,
V 3 VAUX = 3
3.30
30 V
IOUT = 1 mA, CIN = 4.7 F, COUT = 2.2 F
Tempa
Minb
Typc
Maxb
0 mA < IOUT < 400 mA, 4.5 V < 5 VIN
5 VSB < 5.5 V
Full
3.201
3.3
3.399
4.30
4.475
Unit
Regulator Mode
Output Voltage (Regulator)
VO(LDO)
5 VIN Select
Rising Edge of Hysteresis
5 VSB Select
Full
Hysteresis
Full
230
Threshold
Full
4.30
Hysteresis
Full
230
Full
0.3
0.8
Full
0.7
1.6
IO
tPW = 2 ms
Full
eN
BW = 50 Hz to100 kHz, IOUT = 150 mA
Peak Output Current (Regulator)
Output Noise Voltage (Regulator)
3.3
3
3 VOUT
VIN
Room
300
Room
60
10 kHz
Room
40
100 kHz
Room
30
Dynamic Line Regulation
VO(line)
VIN: 4.5 V to 5.5 V
tR/tF = 2 s, IOUT = 150 mA
Room
10
Dynamic Load Regulation
VO(load)
IOUT: 1 mA to 150 mA, tR/tF = 2 s
Room
20
VOUT Turn-On-Time
mA
600
1 kHz
IOUT = 150 mA
V
mV
IO = 0 mA
IGND
V
mV
4.475
IO = 400 mA
Ground Pin Current In Regulator
MODEd
Ripple
pp Rejection
j
(Regulator)
( g
)
Threshold
tON
Room
15
Thermal Shutdown Junction
Temperature
TJ(s/d)
Full
165
Thermal Hysteresis
THYST
Full
20
Short Circuit Current
ISC
3.3 VOUT = 0 V
Room
900
V(rms)
dB
mV
s
_C
C
mA
Bypass Mode (5 VIN = 5 VSB = GND)
Output Voltage
VO(BP)
0 mA < IOUT < 150 mA
Full
Bypass Switch On-Resistance
rDS(on)
3.0 V v VAUX v 3.6 V
Full
0.2
0.35
IGND
0 mA < IOUT < 400 mA
Full
200
400
A
Ground Currentd
3.247
V
Notes
a. Room = 25_C, Full = −40 to 85_C.
b. The algebraic convention whereby the most negative value is a minimum and the most positive a maximum.
c. Typical values are for DESIGN AID ONLY, not guaranteed nor subject to production testing. Typical values at 25_C ambient.
d. Ground pin current includes the IC supply current and the current to drive the linear regulator or bypass switch.
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Document Number: 71340
S-40704—Rev. B, 19-Apr-04
Si91860
Vishay Siliconix
TIMING WAVEFORMS
5V
tON
VIN
0.95 VOUT
VOUT
FIGURE 1. Timing Diagram
PIN CONFIGURATION
SO-8
5 VSB
1
8
GND
5 VIN
2
7
GND
3.3 VOUT
3
6
GND
3.3 VAUX
4
5
GND
Top View
PIN DESCRIPTION
Document Number: 71340
S-40704—Rev. B, 19-Apr-04
Pin Number
Name
Function
1
5 VSB
Secondary power input for the Regulator
2
5 VIN
Primary power input for the Regulator
3
3.3 VOUT
Output 3.3 V
4
3.3 VAUX
Power input for the bypass function
5, 6, 7, 8
GND
Grounds
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Si91860
Vishay Siliconix
ORDERING INFORMATION
Part Number
Temperature Range
Package
Si91860DY-T1
Si91860DY-T1—E3
Tape and Reel
−40 to 85_C
Si91860DY
Bulk
Eval Kit
Temperature Range
Board Type
Si91860DB
−40 to 85_C
Surface Mount
TYPICAL CHARACTERISTICS
1.0
Ground Current vs Temperature (5 VIN or 5 VSB)
Ground Current vs Input Voltage (5 VIN or 5 VSB)
1.0
IOUT = 0
IOUT = 600 mA
IOUT = 400 mA
0.6
Ground Current (mA)
Ground Current (mA)
3.3 VAUX = 0 V
0.8
0.8
IOUT = 200 mA
0.4
IOUT = 0 mA
0.6
0.4
0.2
0.2
5 VIN or 5 VSB = 5 V
0.0
−40
0.0
−20
0
20
40
Temperature
0.35
60
80
0
100
ON-Resistance vs 3.3 VAUX Input Voltage
0.8
Ground Current (mA)
Resistance (Ω)
85_C
0.20
25_C
−40_C
0.15
3.1
3.2
3.3
3.4
3.3 VAUX Input Voltage (V)
4
3
4
5
6
Ground Current vs 3.3 VAUX Input Voltage
0.6
0.25
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2
Input Voltage (V)
0.30
0.10
3.0
1
(oC)
3.5
3.6
5 VIN 5 V
0.4
0.2
0.0
0.0
5 VIN 5 VSB 0 V
0.6
1.2
1.8
2.4
3.0
3.6
3.3 VAUX Input Voltage (V)
Document Number: 71340
S-40704—Rev. B, 19-Apr-04
Si91860
Vishay Siliconix
TYPICAL WAVEFORMS
Load Transient Response-1
VOUT = 10 mV/div
Load Transient Response-2
VOUT = 10 mV/div
IOUT = 100 mA/div
IOUT = 100 mA/div
Input = 5 VIN or 5 VSB
IOUT = 1 to 150 mA
trise = 2 sec
Input = 5 VIN or 5 VSB
IOUT = 150 to 1 mA
tFALL= 2 sec
M 5.00 s
Load Transient Response-3
Load Transient Response-4
VOUT = 50 mV/div
VOUT = 50 mV/div
IOUT = 200 mA/div
IOUT = 200 mA/div
Input = 5 VIN or 5 VSB
IOUT = 0 to 400 mA
trise = 2 sec
M 5.00 s
Input = 5 VIN or 5 VSB
IOUT = 400 to 0 mA
tFALL = 2 sec
5 VIN Power Up (5 VSB = 5 V)
5 VSB
200 mV/div (offset = 5 V)
M 5.00 s
M 5.00 s
5 VIN Power Down (5 VSB = 5 V)
5 VSB
200 mV/div (offset = 5
V)
3.3 VOUT (100 mV/div)
3.3 VOUT (100 mV/div)
5 VIN
500 mV/div (offset = 4.3 V)
5 VIN
500 mV/div (offset = 4.2 V)
5 VSB = 5 V
3.3 VAUX = 0 V
IOUT = 400 mA
Document Number: 71340
S-40704—Rev. B, 19-Apr-04
M 5.00 s
5 VSB = 5 V
3.3 VAUX = 0 V
IOUT = 400 mA
M 5.00 s
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Si91860
Vishay Siliconix
TYPICAL WAVEFORMS
5 VIN Power Down (3.3 VAUX = 3.3 V)
3.3
V
200
AUXmV/div (offset = 3.3 V)
5 VIN Power Up (3.3 VAUX = 3.3 V)
3.3 VAUX
200 mV/div (offset = 3.3 V)
3.3 VOUT (100 mV/div)
3.3 VOUT (100 mV/div)
5 VIN
500 mV/div (offset = 4.3 V)
5 VIN
500 mV/div (offset = 4.2 V)
5 VSB = 0 V
3.3 VAUX = 3.3 V
IOUT = 400 mA
5 VSB = 0 V
3.3 VAUX = 3.3 V
IOUT = 400 mA
M 5.00 s
Line Transient −1 (5 VIN and 5 VSB)
M 5.00 s
Line Transient −2 (5 VIN and 5 VSB)
5 VIN (1 V/div)
5 VIN (2 V/div)
3.3 VOUT (10 mV/div)
3.3 VOUT (10 mV/div)
5 VIN = 4.5 to 5.5 V
IOUT = 150 mA
TRISE = 5 µsec
5 VIN = 5.5 to 4.5 V
IOUT = 150 mA
TTALL = 5 µsec
M 5.00 s
M 5.00 s
Power Supply Ripple Rejection vs. Frequency
0
5 VIN = 5.0 V)
ILOAD = 150 mA
−10
−20
−30
PSRR
−40
−50
PSRR(dB)
−60
−70
−80
1
10
100
1K
10 K
100 K
1M
Frequency (Hz)
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Document Number: 71340
S-40704—Rev. B, 19-Apr-04
Si91860
Vishay Siliconix
BLOCK DIAGRAMS AND TYPICAL APPLICATION CIRCUIT
Si91860
1
5 VSB
4.7 µF
5 VSB
Regulator
Driver
5 VIN
2
3
4.7 µF
3.3 VOUT
2.2 µF
5 VIN
Regulator
Driver
4
3.3 VAUX
4.7 µF
Logic
Control
5, 6
7, 8
DETAIL DESCRIPTION
During normal operation, the 5-VIN input powers the fixed
3.3-V output (3.3 VOUT) through an internal linear regulator.
When 5 VIN falls below 4.07 V, the 3.3-V output is powered
through the linear regulator from 5 VSB. If both 5 VIN and 5 VSB
are below 4.07 V, then the output (3.3 VOUT) is powered from
3.3-VAUX input. The power drawn sequence is from 5 VIN, then
5 VSB and lastly 3.3 VAUX. If both 5 VIN and 5 VSB are above
4.30 V, then 5 VIN will power the output. The device prevents
reverse current from flowing from the output to any unbiased
or low voltage input.
Linear Regulator Mode
The output is regulated at 3.3 V when either one of the 5-VIN
or 5-VSB pins is more than 4.30 V. The 5 VIN takes precedence
when both the 5-VIN and 5-VSB pins are more than valid
threshold voltage (i.e. > 4.30 V). The linear regulator will
regulate the output until both the 5-VIN and 5-VSB pins fall
below 4.07 V.
Document Number: 71340
S-40704—Rev. B, 19-Apr-04
Bypass Mode
When both the 5-VIN and 5-VSB pins fall below 4.07 V, the
output is powered by 3.3 VAUX through a 0.2- internal switch.
Thermal and Over−current Protection
Thermal protection limits total power dissipation in the device.
It safeguards the device in the event of fault conditions. When
the junction temperature exceeds 165_C, the device turns off.
The device turns back on once its junction temperature cools
down by approximately 20_C. The device has overcurrent
protection (typically at 900 mA) when it operates in linear
regulator mode. A continuous short at output pin (3.3 VOUT)
will result in a pulsed output as the thermal protection circuitry
cycles the device on and off. For continuous operation, do not
exceed the junction rating of 150_C. In bypass mode, the
device is not current limited.
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Legal Disclaimer Notice
Vishay
Notice
Specifications of the products displayed herein are subject to change without notice. Vishay Intertechnology, Inc.,
or anyone on its behalf, assumes no responsibility or liability for any errors or inaccuracies.
Information contained herein is intended to provide a product description only. No license, express or implied, by
estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Vishay's
terms and conditions of sale for such products, Vishay assumes no liability whatsoever, and disclaims any express
or implied warranty, relating to sale and/or use of Vishay products including liability or warranties relating to fitness
for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right.
The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications.
Customers using or selling these products for use in such applications do so at their own risk and agree to fully
indemnify Vishay for any damages resulting from such improper use or sale.
Document Number: 91000
Revision: 08-Apr-05
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