LTC4241IGN#TRPBF [Linear]
LTC4241 - PCI-Bus with 3.3V Auxiliary Hot Swap Controller; Package: SSOP; Pins: 20; Temperature Range: -40°C to 85°C;
| 型号： | LTC4241IGN#TRPBF |
| 厂家： | 
Linear |
| 描述： | LTC4241 - PCI-Bus with 3.3V Auxiliary Hot Swap Controller; Package: SSOP; Pins: 20; Temperature Range: -40°C to 85°C PC 输入元件 光电二极管 |
| 文件： | 总16页 (文件大小：300K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC4241
PCI-Bus with 3.3V Auxiliary
Hot Swap Controller
U
FEATURES
DESCRIPTIO
The LTC®4241 is a Hot Swap controller that allows a board
to be safely inserted and removed from a live PCI-bus slot.
It has a primary controller that controls the four PCI
suppliesandanindependentauxiliarycontrollertocontrol
the 3.3V auxiliary supply. External N-channel transistors
areusedtocontrolthe3.3V,5Vand3.3Vauxiliarysupplies
whileon-chipswitchescontrolthe–12Vand12Vsupplies.
The3.3V, 5Vand3.3Vauxiliarysuppliescanberampedup
at an adjustable rate. Electronic circuit breakers protect all
five supplies against overcurrent faults. The foldback
current limit feature reduces current spikes and power
dissipation when shorts occur. The PWRGD output of the
primary controller indicates when all four PCI supplies are
withintolerance.TheFAULToutputindicatesanovercurrent
condition for any of the five supplies.
■
Allows Safe Board Insertion and Removal from a
Live PCI Slot
■
Controls 3.3V, 5V, –12V, 12V and 3.3V Auxiliary
Supplies
Independent 3.3V Auxiliary Supply Hot SwapTM
■
Controller
■
Adjustable Foldback Current Limit with Circuit
Breaker
■
Adjustable Supply Voltage Power-Up Rate
■
High Side Drive for External N-Channel FETs
■
–12V and 12V On-Chip Switches
Fault and Power Good Outputs
■
U
APPLICATIO S
■
PCI-Based Servers
Computer Systems
■
The LTC4241 is available in the 20-pin narrow SSOP
package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
U
TYPICAL APPLICATIO
GND
R1
0.007Ω
Q1
IRF7413
5V
5A
R4
10Ω
R2
0.005Ω
Q2
IRF7413
3.3V
7.6A
R5
10Ω
R3
0.07Ω
Q3
Si2306DS
3.3V
AUX
500mA
SYSTEM
POWER
SUPPLY
C3
10nF
R7
100Ω
R6
10Ω
C1
0.047µF
11
10
9
13
14
15
3
17
16
18
AUXIN AUXSENSE AUXGATE 3V 3V
IN
GATE 3V
5V
IN
5V
5V
SENSE
OUT
SENSE
OUT
8
1
GND
12V
12V
IN
2
20
19
4
500mA
V
12V
EEIN
OUT
12
5
–12V
100mA
AUXON
ON
LTC4241
V
EEOUT
R8 10k
R9 10k
6
7
BACKPLANE
PCI
FAULT
TIMER
CONNECTOR
POWER
C2
0.1µF
SYSTEM
CONTROLLER
PWRGD
LOGIC
RESET
RESET
4241 F01
Figure 1. Hot Swappable PCI and 3.3V Auxiliary Supplies
sn4241 4241f
1
LTC4241
W W U W
U
W
U
ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
(Note 1)
ORDER PART
NUMBER
Supply Voltages
12VIN ................................................................... 14V
V
EEIN .................................................................. –14V
LTC4241CGN
LTC4241IGN
TOP VIEW
AUXIN ................................................................... 7V
Input Voltage
12V
V
1
2
3
4
5
6
7
8
9
12V
V
20
19
18
17
16
15
14
13
12
11
IN
OUT
EEIN
EEOUT
ON .........................................................–0.3V to 14V
AUXON ..................................................–0.3V to 14V
Output Voltages
3V
OUT
5V
OUT
IN
TIMER
5V
5V
ON
FAULT
SENSE
(FAULT, PWRGD) ..................................–0.3V to 14V
Analog Voltages
GATE
3V
PWRGD
GND
SENSE
TIMER, 3VIN, 3VSENSE, GATE,
3V
IN
5VSENSE, 5VIN ............................. –0.3V to (12VIN + 0.3V)
3VOUT, 5VOUT ........................................–0.3V to 14V
AUXSENSE ..........................–0.3V to (AUXIN + 0.3V)
VEEOUT ................................................ –14V to + 0.3V
12VOUT ..................................................–0.3V to 14V
AUXGATE ......................... Internally Limited (Note 3)
Operating Temperature Range
AUXGATE
AUXON
AUXIN
AUXSENSE 10
GN PACKAGE
20-LEAD NARROW PLASTIC SSOP
TJMAX = 150°C, θJA = 135°C/W
LTC4241CGN........................................... 0°C to 70°C
LTC4241IGN........................................–40°C to 85°C
Storage Temperature Range ..................–65°C to 150°C
Lead Temperature (Soldering,10sec).................... 300°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
DC ELECTRICAL CHARACTERISTICS
VAUXIN = 3.3V. (Note 2)
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. V12VIN = 12V, VVEEIN = –12V, V3VIN = 3.3V, V5VIN = 5V,
SYMBOL
PARAMETER
CONDITIONS
ON = V
MIN
TYP
MAX UNITS
I
V
V
Supply Current
Supply Current
●
●
2.5
0.5
8
mA
mA
DD
12VIN
AUXIN
12VIN
AUXON = V
1.5
AUXIN
V
Undervoltage Lockout,
Low-to-High Transition
12V
●
●
●
●
6.5
2.25
3.65
2.35
9
10.8
2.75
4.15
2.85
V
V
V
V
LKO
IN
3V
5V
2.50
3.90
2.60
IN
IN
AUXIN
V
V
V
Undervoltage Lockout Hysteresis
Current Limit Sense Voltage
3V , 5V
AUXIN
20
120
mV
mV
LKH
IN
IN
V
V
= 0V
> 4V
●
●
5.5
40
9
55
14.5
70
mV
mV
SENSE5(TH)
SENSE3(TH)
5VOUT
5VOUT
Threshold (V
– V
)
5VIN
5VSENSE
Current Limit Sense Voltage
Threshold (V – V
V
V
= 0V
> 2V
●
●
5.5
40
9
55
14.5
70
mV
mV
3VOUT
3VOUT
)
3VIN
3VSENSE
t
I
Circuit Breaker Trip Filter Time
(V
(V
– V ) = Step 0 to 100mV
5VSENSE
17
8
µs
µs
CB
5VIN
– V
) = Step 0 to 100mV
AUXSENSE
AUXIN
GATE Pin Output Current
ON High, FAULT High, V
ON Low, FAULT High, V
ON High, FAULT Low, V
= GND
= 5V
●
–20
5
–60
200
25
–100
35
µA
µA
mA
GATE
GATE
GATE
= 5V
GATE
sn4241 4241f
2
LTC4241
DC ELECTRICAL CHARACTERISTICS
VAUXIN = 3.3V. (Note 2)
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. V12VIN = 12V, VVEEIN = –12V, V3VIN = 3.3V, V5VIN = 5V,
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX UNITS
∆V
External Gate Voltage
Internal Switch Voltage Drop
(V
– V
)
GATE
●
100
200
mV
GATE
12VIN
V
(V
(V
– V ), I = 500mA
12VOUT 12VOUT
●
●
200
120
600
250
mV
mV
DROP
12VIN
EEOUT
– V
), I
= 100mA
VEEIN VEEIN
I
I
Current Limit
Current Limit
12V = 12V, 12V
= 0V, TIMER = GND
= 11V, TIMER = GND
●
●
–50
–300 –575
mA
mA
CL(12)
IN
OUT
OUT
12V = 12V, 12V
–525 –850 –1500
IN
V
V
= –12V, V
= –12V, V
= 0V, TIMER = GND
= –11V, TIMER = GND
●
●
50
250
200
450
425
750
mA
mA
CL(VEE)
EEIN
EEIN
EEOUT
EEOUT
T
Thermal Shutdown Temperature
Power Good Threshold Voltage
150
°C
TS
V
V
V
V
V
Rising
Falling
Rising
Rising
●
●
●
●
10.8
11.1
11.4
V
V
V
V
PG(TH)
12VOUT
VEEOUT
3VOUT
5VOUT
–10.2 –10.5 –10.8
2.8
4.5
2.9
4.65
3.0
4.78
V
Power Good Hysteresis
3V
5V
20
30
50
mV
mV
mV
PGH
OUT
OUT
OUT EEOUT
12V , V
V
V
V
Input Low Voltage
ON, AUXON
ON, AUXON
●
●
●
0.8
0.4
V
V
V
IL
Input High Voltage
Output Low Voltage
AUXON Pin Input Current
2
IH
OL
FAULT, PWRGD , I = 3mA
OL
I
AUXON = GND
●
●
±0.08
±0.08
±10
±10
µA
µA
IN
AUXON = V
AUXIN
ON Pin Input Current
ON = GND
●
●
±0.08
±0.08
±10
±10
µA
µA
ON = V
12VIN
5V
3V
Input Current
Input Current
5V
3V
= 5V
●
●
●
●
●
●
50
50
100
100
900
550
500
350
µA
µA
µA
µA
µA
µA
SENSE
SENSE
SENSE
= 3V
SENSE
5V Input Current
IN
5V = 5V
IN
580
310
260
150
3V Input Current
IN
3V = 3V
IN
5V
OUT
3V
OUT
Input Current
Input Current
5V
OUT
3V
OUT
= 5V, ON = V
= 3V, ON = V
12VIN
12VIN
R
DIS
5V
3V
Discharge Impedance
Discharge Impedance
OUT
ON = GND
ON = GND
ON = GND
ON = GND
60
50
450
1600
Ω
Ω
Ω
Ω
OUT
OUT
12V
Discharge Impedance
Discharge Impedance
V
EEOUT
I
TIMER Pin Current
Timer On, V
Timer Off, V
= GND,
= 5V,
●
●
–15
0.5
–22
45
–27
1.3
µA
TIMER
TIMER
TIMER
mA
V
V
TIMER Threshold Voltage
TIMER
AUXCB
(V
12VIN
– V
)
0.9
50
V
TIMER
Circuit Breaker Trip Voltage
(V – V
)
AUXSENSE
●
●
40
–6
60
mV
AUXIN
I
AUXGATE Gate Output Current
AUXON High, FAULT High, V
AUXON Low, FAULT High, V
AUXON High, FAULT Low, V
= GND
= 5V
= 10V
–10
200
50
–14
µA
µA
mA
AUXGATE
AUXGATE
AUXGATE
AUXGATE
∆V
AUXGATE
External AUXGATE Gate Voltage
(V
AUXGATE
– V
), V = 3.3V
AUXIN AUXIN
●
5
8
11
V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2 : All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground unless otherwise
specified.
Note 3 : An internal zener on the AUXGATE pin clamps the charge pump
voltage to a typical maximum operating voltage of 12V. External overdrive
of the AUXGATE pin beyond the internal zener voltage may damage the
device.
sn4241 4241f
3
LTC4241
U W
TYPICAL PERFOR A CE CHARACTERISTICS
3.3V and 5V Current
Foldback Profile
–12V Current Foldback Profile
12V Current Foldback Profile
1100
1000
900
800
700
600
500
400
300
200
100
0
12
10
8
1100
1000
900
800
700
600
500
400
300
200
100
0
12V = 12V
IN
V
= –12V
EEIN
3V
OUT
5V
OUT
6
4
3V = 3.3V
IN
2
5V = 5V
IN
SENSE
R
= 0.005Ω
0
0
1
2
3
4
5
6
7
8
9
10 11 12
0.5
1.5
2.5
3.5
4.5
5.5
0
–1 –2 –3 –4 –5 –6 –7 –8 –9 –10 –11–12
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
4241 • G02
4241 • G01
4241 • G03
12VIN Current Limit
vs Temperature
5VIN Current Limit Voltage
vs Temperature
3VIN Current Limit Voltage
vs Temperature
70
60
50
40
30
20
10
0
1200
1000
800
600
400
200
0
70
60
50
40
30
20
10
0
3V
= 3.3V
5V
= 5V
OUT
OUT
12V
= 11V
OUT
12V
= 0V
5V
= 0V
OUT
3V
= 0V
OUT
OUT
–75 –50 –25
75 100 125 150
–75 –50 –25
75 100 125 150
–75 –50 –25
75 100 125 150
TEMPERATURE (°C)
0
25 50
0
25 50
0
25 50
TEMPERATURE (°C)
TEMPERATURE (°C)
4241 • G05
4241 • G06
4241 • G04
(VAUXIN – VAUXSENSE
)
VEEIN Current Limit
vs Temperature
Circuit Breaker Trip Voltage
vs Temperature
GATE, AUXGATE Output Source
Current vs Temperature
12.5
12.0
11.5
11.0
10.5
10.0
9.5
90
80
70
60
50
40
30
20
10
55
54
53
52
51
50
49
48
47
46
45
600
500
400
300
200
100
0
V
= –11V
EEOUT
GATE
AUXGATE
V
= 0V
EEOUT
9.0
8.5
–75 –50 –25
75 100 125 150
TEMPERATURE (°C)
–75 –50 –25
75 100 125 150
–75 –50 –25
75 100 125 150
0
25 50
0
25 50
TEMPERATURE (°C)
0
25 50
TEMPERATURE (°C)
4241 • G08
4241 • G09
4241 • G07
sn4241 4241f
4
LTC4241
U W
TYPICAL PERFOR A CE CHARACTERISTICS
(VAUXGATE – VAUXIN
vs Temperature
)
GATE, AUXGATE Output Sink
Current vs Temperature
GATE, AUXGATE Fast Pull-Down
Current vs Temperature
8.20
8.15
8.10
8.05
8.00
7.95
7.90
7.85
7.80
7.75
350
300
250
200
150
100
50
80
70
60
50
40
30
20
10
0
AUXIN = 3.3V
GATE
AUXGATE
AUXGATE
GATE
–75 –50 –25
75 100 125 150
–75 –50 –25
75 100 125 150
TEMPERATURE (°C)
–75 –50 –25
75 100 125 150
TEMPERATURE (°C)
0
25 50
0
25 50
0
25 50
TEMPERATURE (°C)
4241 • G12
4241 • G10
4241 • G11
VEE Internal Switch Voltage Drop
vs Temperature
12V Internal Switch Voltage Drop
vs Temperature
AUXGATE Voltage vs Temperature
325
300
275
250
225
200
175
150
125
100
11.75
11.60
11.45
11.30
11.15
11.00
10.85
10.70
200
180
160
140
120
100
80
I
= 500mA
I
= 100mA
VEEIN
12VOUT
60
40
–75 –50 –25
75 100 125 150
0
TEMPERATURE (°C)
–75 –50 –25
75 100 125 150
TEMPERATURE (°C)
25 50
–75 –50 –25
75 100 125 150
0
TEMPERATURE (°C)
0
25 50
25 50
4241 • G14
4241 • G13
4241 • G15
Power Good Threshold Voltage
Power Good Threshold Voltage
Power Good Threshold Voltage
vs Temperature (12VOUT
)
vs Temperature (5VOUT
)
vs Temperature (3VOUT
)
11.20
11.15
11.10
11.05
11.00
10.95
10.90
4.68
4.67
4.66
4.65
4.64
4.63
4.62
4.61
4.60
2.915
2.910
2.905
2.900
2.895
2.890
2.885
2.880
2.875
–75 –50 –25
75 100 125 150
0
25 50
–75 –50 –25
75 100 125 150
0
25 50
–75 –50 –25
75 100 125 150
0
25 50
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
4241 • G16
4241 • G17
4241 • G18
sn4241 4241f
5
LTC4241
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Power Good Threshold Voltage
Timer Threshold Voltage
vs Temperature
Timer Current vs Temperature
vs Temperature (VEEOUT
)
–10.60
–10.55
–10.50
–10.45
–10.40
–10.35
–10.30
0.950
0.925
0.900
0.875
0.850
0.825
0.800
0.775
0.750
23.00
22.75
22.50
22.25
22.00
21.75
21.50
21.25
21.00
V
– V
TIMER
12VIN
–75 –50 –25
75 100 125 150
–75 –50 –25
75 100 125 150
0
TEMPERATURE (°C)
–75 –50 –25
75 100 125 150
TEMPERATURE (°C)
0
25 50
25 50
0
25 50
TEMPERATURE (°C)
4241 • G19
4241 • G20
4241 • G21
12VIN Undervoltage Lockout
Threshold vs Temperature
VEEIN, 5VIN, 3VIN, AUXIN Supply
Current vs Temperature
12VIN Supply Current
vs Temperature
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
700
650
600
550
500
450
400
350
300
250
200
9.20
9.15
9.10
9.05
9.00
8.95
8.90
8.85
8.80
5V
IN
AUXIN
V
EEIN
3V
IN
–75 –50 –25
75 100 125 150
–75 –50 –25
75 100 125 150
TEMPERATURE (°C)
0
25 50
0
25 50
–75 –50 –25
75 100 125 150
0
25 50
TEMPERATURE (°C)
TEMPERATURE (°C)
4241 • G22
4241 • G23
4241 • G24
(V5VIN – V5VSENSE), (VAUXIN
–
5VIN Undervoltage Lockout
Threshold vs Temperature
3VIN, AUXIN Undervoltage Lockout
Threshold vs Temperature
VAUXSENSE) Circuit Breaker Trip
Filter Time vs Temperature
18.50
18.25
18.00
17.75
17.50
17.25
17.00
16.75
16.50
8.3
8.2
8.1
8.0
7.9
7.8
7.7
7.6
7.5
3.950
3.925
3.900
3.875
3.850
3.825
3.800
2.650
2.625
2.600
2.575
2.550
2.525
2.500
2.475
2.450
AUXIN
V
– V
AUXIN
AUXSENSE
V
– V
5VIN
5VSENSE
3V
IN
–75 –50 –25
75 100 125 150
0
TEMPERATURE (°C)
–75 –50 –25
75 100 125 150
TEMPERATURE (°C)
–75 –50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
25 50
0
25 50
4241 • G27
4241 • G25
4241 • G26
sn4241 4241f
6
LTC4241
U
U
U
PI FU CTIO S
12VIN (Pin 1): 12V Supply Input. This pin powers the
primary controller internal circuitry. A 0.5Ω switch is
connected between 12VIN and 12VOUT with a foldback
current limit. An undervoltage lockout circuit prevents the
switches from turning on while the 12VIN pin voltage is
less than 9V.
power good threshold voltage, PWRGD will go high after
a15µsdeglitchingtime.Theswitcheswillnotbeturnedoff
when PWRGD goes high.
GND (Pin 8): Chip Ground
AUXGATE (Pin 9): High Side Gate Drive for the 3.3V
Auxiliary External N-channel MOSFET. An internal charge
pump generates at least 8V of gate drive from a 3.3V
auxiliary supply. A zener clamps AUXGATE approximately
12V above the supply voltage at AUXIN. The rise time at
AUXGATE is set by an external AUXGATE capacitor con-
nected to ground and an internal 10µA current source
provided by the charge pump. If the circuit breaker trips or
the auxiliary supply voltage hits the undervoltage lockout
threshold, a 50mA current sink rapidly pulls AUXGATE
low.
VEEIN (Pin 2): –12V Supply Input. A 1.2Ω switch is
connected between VEEIN and VEEOUT with a foldback
current limit.
3VOUT (Pin 3): 3.3V Output Monitor. Used to monitor the
3.3V output supply voltage. The PWRGD signal cannot go
low until the 3VOUT pin exceeds 2.9V.
TIMER (Pin 4): Current Limit Fault Timer Input. Connect a
capacitor from TIMER to ground. With the primary con-
troller turned off (ON = GND) or the internal circuit breaker
trippedduetoaPCIsupplyfault(FAULT=low), theTIMER
pin is internally held at ground. When the primary control-
ler is turned on, a 22µA pull-up current source is con-
nectedtoTIMER.CurrentlimitfaultsfromthePCIsupplies
will be ignored until the voltage at the TIMER pin rises to
within 0.9V of 12VIN.
AUXSENSE (Pin 10): 3.3V Auxiliary Circuit Breaker Cur-
rent Sense Input. The load current is monitored by a sense
resistor connected between AUXIN and AUXSENSE. The
circuitbreakertripsifthevoltageacrossthesenseresistor
exceeds50mVandtheAUXGATEpinvoltagewillbeturned
off.
ON (Pin 5): On Control Input. A rising edge turns on the
external N-channel FETs for 3.3V and 5V PCI supplies, the
internal 12V and –12V switches and a falling edge turns it
off. If the ON pin is cycled low then high following the trip
of the circuit breaker due to a PCI supply fault, the circuit
breaker is reset.
AUXIN (Pin 11): 3.3V Auxiliary Supply Input. This pin
powers the auxiliary controller internal circuitry. An
undervoltage lockout circuit disables the AUXGATE pin
until the supply voltage at AUXIN is greater than 2.6V.
AUXGATEisheldatgroundpotentialuntiltheundervoltage
lockoutdeactivates.Ifno3.3Vauxiliarysupplyisavailable,
tie AUXIN to ground.
FAULT (Pin 6): Fault Output. Open drain logic output used
by both the primary and auxiliary controller to indicate an
overcurrent fault condition. When any of the PCI and 3.3V
auxiliary supplies are in current limit fault, the controller
detecting the fault (primary or auxiliary) will be latched off
and the FAULT pin will be pulled low. Current limit faults
from the PCI supplies are ignored while the voltage at the
TIMER pin is less than (12VIN – 0.9V). The current limit
fault detected by the primary controller will not cause the
auxiliary controller to latch off and vice versa.
AUXON (Pin 12): ON Control Input for Auxiliary Supply. A
rising edge turns on the external N-channel FET for 3.3V
auxiliarysupplyandafallingedgeturnsitoff.IftheAUXON
pin is cycled low then high following the trip of the circuit
breaker due to a 3.3V auxiliary supply fault, the circuit
breaker is reset.
3VIN (Pin 13): 3.3V Supply Sense Input. An undervoltage
lockout circuit prevents the switches from turning on
whenthevoltageatthe3VIN pinislessthan2.5V.Ifno3.3V
input supply is available, tie 3VIN to the 5VIN pin.
PWRGD (Pin 7): Power Good Output. Open drain logic
output used by the primary controller to indicate the
voltage status of the PCI supplies. PWRGD remains low
while V12VOUT ≥ 11.1V, V3VOUT ≥ 2.9V, V5VOUT ≥ 4.65V,
3VSENSE (Pin14): 3.3VCurrentLimitSetPin. Withasense
resistor placed in the supply path between 3VIN and
3VSENSE, the GATE pin voltage will be adjusted to maintain
V
VEEOUT ≤–10.5V. Whenoneofthesuppliesfallsbelowits
sn4241 4241f
7
LTC4241
U
U
U
PI FU CTIO S
a constant voltage across the sense resistor and a
constant current through the switch. A foldback feature
makes the current limit decrease as the voltage at the
3VOUT pinapproachesground.Todisablethecurrentlimit,
3VSENSE and 3VIN can be shorted together.
the current limit decrease as the voltage at the 5VOUT pin
approaches ground. To disable the current limit, 5VSENSE
and 5VIN can be shorted together.
5VIN (Pin17):5VSupplySenseInput. Usedtomonitorthe
5V input supply voltage. An undervoltage lockout circuit
prevents the switches from turning on when the voltage at
the 5VIN pin is less than 3.9V.
GATE (Pin 15): High Side Gate Drive for the 3.3V and 5V
PCI Supplies External N-channel MOSFETs. Requires an
external series RC network for the current limit loop
compensation and setting the minimum ramp-up rate.
During power-up, the slope of the voltage rise at the GATE
is set by the internal 60µA pull up current source and the
external GATE capacitor connected to ground. During
power-down, the slope of the falling voltage is set by the
200µA current source connected to ground and the exter-
nal GATE capacitor.
5VOUT (Pin 18): 5V Output Monitor. Used to monitor the
5V output supply voltage. The PWRGD signal cannot go
low until the 5VOUT pin exceeds 4.65V.
V
EEOUT (Pin 19): –12V Supply Output. A 1.2Ω switch is
connected between VEEIN and VEEOUT. VEEOUT must
fall below –10.5V before the PWRGD signal can go low on
the LTC4241.
12VOUT (Pin 20): 12V Supply Output. A 0.5Ω switch is
connected between 12VIN and 12VOUT. 12VOUT must
exceed 11.1V before the PWRGD signal can go low on the
LTC4241
5VSENSE (Pin 16): 5V Current Limit Set Pin. With a sense
resistor placed in the supply path between 5VIN and
5VSENSE, the GATE pin voltage will be adjusted to maintain
a constant voltage across the sense resistor and a con-
stantcurrentthroughtheswitch.Afoldbackfeaturemakes
sn4241 4241f
8
LTC4241
W
BLOCK DIAGRA
5V
5V
GATE
15
3V
3V
3V
5V
OUT
IN
SENSE
SENSE
14
IN
OUT
3
17
16
13
18
+
–
12V
IN
+
–
5V
3V
OUT
OUT
60µA
+
–
+
–
A2
55mV
A1
55mV
Q8
Q7
+
+
–
–
200µA
Q5
3.9V
UVL
2.5V
UVL
5
7
ON
C
P1
+
PWRGD
Q3
Q4
–
REF
PRIMARY CONTROL LOGIC
CP2
6
FAULT
+
–
REF
9V
UVL
REF
12V
IN
Q9
Q10
Q2
Q1
22µA
CP4
CP3
+
–
+
–
Q6
PCI-BUS HOT SWAP
CONTROLLER
REF
1
20
12V
4
2
19
8
12V
IN
TIMER
V
V
EEOUT
GND
OUT
EEIN
Q12
CHARGE
PUMP
11
AUXIN
+
–
50mV
10µA
AUXILIARY
CONTROL
LOGIC
+
8µs
FILTER
A3
AUXGATE
9
Q11
AUXSENSE
AUXON
10
12
–
Z1
12V
Z2
20V
2.6V
UVL
200µA
AUXIN
3.3V AUXILIARY SUPPLY
HOT SWAP CONTROLLER
4241 BD
sn4241 4241f
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LTC4241
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APPLICATIO S I FOR ATIO
Hot Circuit Insertion
8. Fault control: the current limit fault detected by either
the primary or auxiliary controller will not cause the other
controller to latch off. Both controllers use the FAULT
output to indicate a fault condition.
When a circuit board is inserted into a live PCI slot, the
supply bypass capacitors on the board can draw huge
transient currents from the PCI power bus as they charge
up. The transient currents can cause permanent damage
to the connector pins and glitches the power bus, causing
other boards in the system to reset.
9. Space saving 20-pin narrow SSOP package.
PCI Power Requirements
PCI systems usually require four power rails: 5V, 3.3V,
–12V and 12V. Systems implementing the 3.3V signaling
environmentareusuallyrequiredtoprovideallfourrailsin
every system.
TheLTC4241isdesignedtoturnaboard’ssupplyvoltages
on and off in a controlled manner, allowing the board to be
safely inserted or removed from a live PCI slot without
glitching the system power supplies. The chip also pro-
tects the PCI supplies from shorts and monitors the
supply voltages.
A 3.3VauxiliarysupplyisaddedinthePCIsystemtopower
PCI logic functions that need to remain active when the
rest of the system is unpowered.
The LTC4241 is designed for motherboard applications
and includes an additional independent controller for the
3.3V auxiliary supply.
The tolerance of the supplies as measured at the compo-
nents is summarized in Table 1.
Table 1. PCI Power Supply Requirements
CAPACITIVE
LTC4241 Feature Summary
1. Allows safe board insertion and removal from a
motherboard.
SUPPLY
TOLERANCE
LOAD
<3000µF
<3000µF
<500µF
<120µF
<500µF
5V
5V ± 5%
3.3V
12V
3.3V ± 0.3V
12V ± 5%
2. Primary controller to control the four PCI supplies:
3.3V, 5V, –12V, 12V and an independent auxiliary control-
ler to control the 3.3V auxiliary supply.
–12V
–12V ± 10%
3.3V ± 0.3V
3.3V
AUX
3. Adjustable foldback current limit for PCI supplies: an
adjustable analog current limit with a value that depends
on the output voltage. If the output is shorted to ground,
the current limit drops to keep power dissipation and
supply glitches to a minimum.
Power-Up Sequence for PCI Power Supplies
The PCI power supplies are controlled by placing external
N-channel pass transistors in the 3.3V and 5V power
paths, and internal pass transistors for the 12V and –12V
power paths (Figure 1).
4. Electronic circuit breaker for all supplies: if a supply
remainsincurrentlimitfortoolong,thecircuitbreakerwill
trip, the supplies will be turned off and the FAULT pin
pulled low.
Resistors R1 and R2 provide a current signal for fault
detection and R7 and C1 provide current control loop
compensation. Resistors R4 and R5 prevent high fre-
quency oscillations in Q1 and Q2.
5. Current limit power-up: the four PCI supplies are
allowed to power up in current limit. This allows the chip
to power up boards with a wide range of capacitive loads
without tripping the circuit breaker. The maximum allow-
ablepower-uptimeisprogrammableusingtheTIMERpin.
WhentheONpinispulledhigh, theGATEpinispulledhigh
by an internal 60µA current source and the pass transis-
tors are allowed to turn on. The internal 12V and –12V
switches are also turned on and a 22µA current source is
connected to the TIMER pin (Figure 2).
6. On-Chip –12V and 12V power switches
7. Power good output: monitors the voltage status of the
four PCI supply voltages. The 3.3V auxiliary supply is not
monitored.
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ON
10V/DIV
ON
10V/DIV
TIMER
10V/DIV
TIMER
10V/DIV
GATE
10V/DIV
GATE
10V/DIV
12V
OUT
5V/DIV
12V
OUT
5V/DIV
5V
OUT
3V
OUT
5V/DIV
5V/DIV
5V
OUT
3V
OUT
5V/DIV
5V/DIV
V
EEOUT
5V/DIV
V
EEOUT
5V/DIV
FAULT
10V/DIV
FAULT
10V/DIV
PWRGD
10V/DIV
PWRGD
10V/DIV
4241 F03
4241 F02
10ms/DIV
10ms/DIV
Figure 3. Normal Power-Down Sequence
Figure 2. Normal Power-Up Sequence
The current in each pass transistor increases until it
reaches the current limit for each supply. Each supply is
allowed to power up at the rate dV/dt = 60µA/C1 or as
determined by the current limit and the load capacitance
onthesupplyline, whicheverisslower. Currentlimitfaults
are ignored while the TIMER pin voltage is ramping up and
is less than 0.9V below 12VIN. Once all four PCI supply
voltagesarewithintolerance, thePWRGDpinwillpulllow.
Timer
During a power-up sequence for the PCI power supplies,
a 22µA current source is connected to the TIMER pin and
current limit faults are ignored until the voltage ramps to
within 0.9V of 12VIN. This feature allows the chip to power
up a PCI slot that can accommodate boards with a wide
range of capacitive loads on the supplies. The power-up
time for any one of the four outputs will be:
Power-Down Sequence for PCI Power Supplies
CLOAD •VOUT
ILIMIT – ILOAD
tON 2•
When the ON pin is pulled low, a power-down sequence
begins for all the PCI power supplies (Figure 3).
For example, for CLOAD = 2000µF, VOUT = 5V, ILIMIT = 7A,
ILOAD = 5A, the 5VOUT turn-on time will be ~10ms. By
substituting the variables in the above equation with the
appropriate values, the turn-on time for the other three
outputs can be calculated. The timer period should be set
longer than the maximum supply turn-on time but short
enough to not exceed the maximum safe operating area of
the pass transistor during a short-circuit. The timer period
is given by:
Internal switches are connected to each of the output
supply voltage pins to discharge the load capacitors to
ground. The TIMER pin is immediately pulled low and the
internal 12V and –12V switches are turned off. The GATE
pin is pulled to ground by an internal 200µA current
source. This turns off the external pass transistors in a
controlled manner and prevents the load current on the
3.3V and 5V supplies from going to zero instantaneously
and glitching the power supply voltages. When any of the
output voltages dips below its threshold, the PWRGD pin
pulls high.
CTIMER •11.1V
tTIMER
=
22µA
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For CTIMER = 0.1µF, the timer period will be ~50ms. The
spikes — for example, from a fan turning on — from
causing false trips of the circuit breaker. The chip will stay
in the latched-off state until the ON pin is cycled low then
high, or the 12VIN supply is cycled.
TIMER pin is immediately pulled low when ON goes low.
Thermal Shutdown
The internal switches for the 12V and –12V supplies are
protected by an internal current limit and thermal shut-
down circuit. When the temperature of the chip reaches
150°C, only the switches controlling the PCI supplies will
be latched off and the FAULT pin will be pulled low.
To prevent excessive power dissipation in the pass tran-
sistors and to prevent voltage spikes on the supplies
during short-circuit conditions, the current limit on each
PCI supply, except the 3.3V auxiliary supply, is designed
tobeafunctionoftheoutputvoltage.Astheoutputvoltage
drops, the current limit decreases. Unlike a traditional
circuit breaker function where huge currents can flow
before the breaker trips, the current foldback feature
assures that the supply current will be kept at a safe level
and prevent voltage glitches when powering up into a
short.
Short-Circuit Protection for PCI Power Supplies
During a normal power-up sequence for the PCI power
supplies, if the TIMER is done ramping and any supply is
still in current limit, all of the pass transistors will be
immediately turned off, the TIMER and FAULT pin will be
pulled low as shown in Figure 4.
ON
10V/DIV
ON
10V/DIV
TIMER
10V/DIV
TIMER
10V/DIV
GATE
10V/DIV
GATE
10V/DIV
12V
OUT
5V/DIV
12V
OUT
5V/DIV
5V
OUT
3V
OUT
5V/DIV
5V/DIV
5V
OUT
3V
OUT
5V/DIV
5V/DIV
V
V
EEOUT
EEOUT
5V/DIV
5V/DIV
FAULT
10V/DIV
FAULT
10V/DIV
PWRGD
10V/DIV
PWRGD
10V/DIV
4241 F05
4241 F04
20ms/DIV
20ms/DIV
Figure 4. Power-Up into a Short on 3.3V Output
Figure 5. Short-Circuit on 5V Followed by Circuit Breaker Reset
Ifashort-circuitoccursafterthePCIsuppliesarepowered
up, the shorted supply’s current will drop immediately to
the limit value (Figure 5).
The current limit and the foldback current level for the 5V
and 3.3V outputs are both a function of the external sense
resistor (R1 for 5VOUT and R2 for 3VOUT, see Figure 1). As
shown in Figure 1, a sense resistor is connected between
5VIN and 5VSENSE for the 5V supply. For the 3V supply, a
If the supply remains in current limit for more than 17µs,
all of the PCI supplies except the 3.3V auxiliary supply will
be latched off. The 17µs delay prevents quick current
sense resistor is connected between 3VIN and 3VSENSE
.
sn4241 4241f
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The current limit and the foldback current level (at the
power path (Figure 1). The resistor R3 provides load
current fault detection and R6 prevents high frequency
oscillation in Q3.
V
OUT = 0V) are given by:
ILIMIT = 55mV/RSENSE
IFOLDBACK = 9mV/RSENSE
When power is first applied to VAUXIN, the AUXGATE pin
pulls low. A low-to-high transition at the AUXON pin
initiates the AUXGATE ramp up (Figure 7). The AUXGATE
is pulled high by an internal 10µA current source and the
pass transistor is allowed to turn on. As the auxiliary
controller does not have the foldback current limit feature
andtimercontrol,theinrushsupplycurrentduringpower-
up is limited by ramping the gate of the pass transistor at
a controlled rate (dV/dt = 10µA/C3) where C3 is the total
external capacitance between AUXGATE and ground.
With proper selection of the C3 capacitance value, the
inrush current (I = CLOAD • dV/dt = 10µA • CLOAD/C3) is
limitedtoavaluelessthanthecurrentlimitsetbythesense
resistorR3. Thispreventsthecircuitbreakerfromtripping
during power-up. CLOAD is the total load capacitance on
the 3.3V auxiliary supply line. For example, for C3 = 10nF,
CLOAD = 470µF, R3 = 0.07Ω, ILIMIT = 0.7A, the inrush
current will be 0.47A < ILIMIT. The ramp-up time for
3.3VAUX output to reach its final value is equal to
t = (VAUXIN • C3)/10µA.
As a design aid, the current limit and foldback level for
commonly used values for RSENSE are given in Table 2.
Table 2. ILIMIT and IFOLDBACK vs RSENSE
R
SENSE
(Ω)
I
I
FOLDBACK
LIMIT
0.005
0.006
0.007
0.008
0.009
0.01
11A
1.8A
9.2A
7.9A
6.9A
6.1A
5.5A
1.5A
1.3A
1.1A
1.0A
0.9A
The current limit for the internal 12V switch is set at
850mA folding back to 300mA and the –12V switch at
450mA folding back to 200mA.
In systems where it is possible to exceed the current limit
for a short amount of time, it might be necessary to
prevent the analog current loop from responding quickly
so the output voltage does not droop. This can be accom-
plished by adding an RC filter across the sense resistor as
shown in Figure 6. RF should be 20Ω or less to prevent
offset errors. A capacitor, CF, of 0.1µF gives a delay of
about 1.5µs and a 1µF capacitor gives a delay of about
15µs.
A high-to-low transition at the AUXON pin initiates a
AUXGATE ramp-down at a slope of –200µA/C3 as the
AUXGATEispulledtogroundbyaninternal200µAcurrent
source. This will allow the load capacitance on the supply
line to discharge while the AUXGATE pulls low to turn off
the external N-channel pass transistor.
R1
0.007Ω
Q1
IRF7413
1
2
5V
OUT
5A
5V
IN
3
4
AUXON
2V/DIV
C
F
1µF
R
R4
10Ω
F
20Ω
R7
AUXGATE
5V/DIV
100Ω
17
16
5V
SENSE
15
GATE 5V
18
C1
0.047µF
5V
IN
OUT
*ADDITIONAL PINS
OMITTED FOR
CLARITY
LTC4241*
3.3V
AUX
2V/DIV
Figure 6. Delay in the Current Limit Loop
4241 F07
5ms/DIV
Power-Up/Down Sequence for 3.3V Auxiliary Supply
Figure 7. Power-Up/Down Sequence for 3.3V Auxiliary Supply
The 3.3V auxiliary supply is controlled by placing an
external N-channel pass transistor Q3 in the 3.3VAUX
sn4241 4241f
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Electronic Circuit Breaker for 3.3V Auxiliary Supply
Supply Bypass Capacitors
An electronic circuit breaker is used to protect against In motherboard applications, large bypass capacitors are
excessive load current and short-circuits on the 3.3V recommended at each of the system power supplies to
auxiliary supply. The load current is monitored by placing minimize supply glitches as a result of board insertion. A
a sense resistor R3 between AUXIN and AUXSENSE as supply bypass capacitor of ≥100µF at 12VIN connection is
shown in Figure 1. The circuit breaker trip threshold is recommended.
50mV and exhibits a response time of 8µs. Unlike the PCI
CURRENT FLOW
FROM SUPPLY
CURRENT FLOW
TO LOAD
supplies which use the current foldback limit with circuit
breaker during short-circuits, here the circuit breaker will
trip and immediately pull AUXGATE to ground if the
voltagebetweenAUXINandAUXSENSEexceeds50mVfor
morethan8µs.TheexternalN-channeltransistoristurned
off and FAULT is pulled low. The circuit breaker is reset
when AUXON is cycled low then high, or the AUXIN supply
is cycled. If the circuit breaker feature is not required, the
AUXSENSE pin can be shorted to AUXIN.
SENSE RESISTOR
TRACK WIDTH W:
0.03" PER AMPERE
W
ON 1 OZ COPPER FOIL
4241 F08
5V
5V
IN
SENSE
Figure 8. Making PCB Connections to
the Sense Resistor for the 5V Rail
The trip current of the circuit breaker is set by:
PCB Layout Considerations for the Sense Resistor
ITRIP = 50mV/R3
For proper circuit breaker operation, 4-wire Kelvin-sense
connectionsbetweenthesenseresistorandtheLTC4241’s
5VIN and 5VSENSE pins, 3VIN and 3VSENSE pins and AUXIN
and AUXSENSE pins are strongly recommended. The
drawing in Figure 8 illustrates the correct way of making
connections between the LTC4241 and the sense resistor.
PCB layout should be balanced and symmetrical to mini-
mize wiring errors. In addition, the PCB layout for the
sense resistors and the power MOSFETs should include
good thermal management techniques for optimal sense
resistor power dissipation.
As a design aid, the trip current for commonly used values
for R3 is given in Table 3.
Table 3. ITRIP vs R3
R3 (Ω)
0.05
0.06
0.07
0.08
0.09
0.1
I
TRIP
1A
833mA
714mA
625mA
556mA
500mA
Power MOSFET and Sense Resistor Selection
If more than 8µs of response time is needed to reject
supply current ripple noise, an external resistor, RF, of
20Ω and capacitor, CF, of 1µF (Figure 6) can be added to
the AUXSENSE circuit. This will give a delay of 15µs.
Table 4 lists some available N-channel power MOSFETs .
Table5listssomecurrentsenseresistorsthatcanbeused
with the LTC4241’s circuit breakers. Table 6 lists the
supplier web site addresses for discrete components
mentioned throughout this datasheet.
Table 4. N-Channel Power MOSFET Selection Guide
CURRENT
RATING
PART NUMBER
PACKAGE
V
DS
MAX
V
GS
MAX
R
DS(on)
MANUFACTURER
8.0A
3.5A
10A
13A
2.7A
Si4412ADY
Si2306DS
Si4410DY
IRF7413
SO-8
SOT-23
SO-8
30V
±20V
±20V
±20V
±20V
±20V
0.024Ω
0.057Ω
0.013Ω
0.011Ω
0.046Ω
Vishay-Siliconix
Vishay-Siliconix
30V
30V
30V
30V
Vishay-Siliconix
SO-8
International Rectifier
FDN 359AN
SOT-23
Fairchild Semiconductor
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Table 5. Sense Resistor Selection Guide
CURRENT LIMIT VALUE
PART NUMBER
DESCRIPTION
MANUFACTURER
0.7A
1A
WSL2010R07
0.07Ω, 0.5W, 1% Resistor
0.055Ω, 0.5W, 1% Resistor
Vishay-Dale
LR120601R055F
WSL2010R055
IRC-TT
Vishay-Dale
2A
5A
LR120601R028F
WSL2010R028
0.028Ω, 0.5W, 1% Resistor
0.011Ω, 0.5W, 1% Resistor
IRC-TT
Vishay-Dale
LR120601R011F
WSL2010R011
IRC-TT
Vishay-Dale
7.9A
11A
WSL2512R007
WSL2512R005
0.007Ω, 1W, 1% Resistor
0.005Ω, 1W, 1% Resistor
Vishay-Dale
Vishay-Dale
Table 6. Manufacturers’ Web Site
MANUFACTURER
International Rectifier
Fairchild Semiconductor
IRC-TT
WEB SITE
www.irf.com
www.fairchildsemi.com
www.irctt.com
Vishay-Dale
www.vishay.com
www.vishay.com
www.diodes.com
Vishay-Siliconix
Diodes, Inc.
U
PACKAGE DESCRIPTIO
GN Package
20-Lead Plastic SSOP (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1641)
.337 – .344*
(8.560 – 8.737)
.058
(1.473)
REF
.045 ±.005
20 19 18 17 16 15 14 13 12 11
.254 MIN
.150 – .165
.229 – .244
.150 – .157**
(5.817 – 6.198)
(3.810 – 3.988)
.0165 ±.0015
.0250 TYP
1
2
3
4
5
6
7
8
9 10
RECOMMENDED SOLDER PAD LAYOUT
.015 ± .004
(0.38 ± 0.10)
.053 – .068
(1.351 – 1.727)
.004 – .0098
(0.102 – 0.249)
× 45°
.007 – .0098
(0.178 – 0.249)
0° – 8° TYP
.016 – .050
(0.406 – 1.270)
.008 – .012
(0.203 – 0.305)
.0250
(0.635)
BSC
NOTE:
1. CONTROLLING DIMENSION: INCHES
INCHES
(MILLIMETERS)
2. DIMENSIONS ARE IN
GN20 (SSOP) 0502
3. DRAWING NOT TO SCALE
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
sn4241 4241f
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
15
LTC4241
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TYPICAL APPLICATIO
GND
R1
0.007Ω
Q1
IRF7413
5V
5A
1
2
3
4
R4
10Ω
R3
0.07Ω
Q3
3.3V
AUX
Si4412ADY
1
2
500mA
SYSTEM
POWER
SUPPLY
3
4
C3
10nF
R7
100Ω
R6
10Ω
C1
0.047µF
11
10
9
13
17
14
16
15
3
18
AUXIN AUXSENSE AUXGATE 3V
GND
5V
3V
5V
GATE 3V
5V
IN
IN
SENSE SENSE
OUT
OUT
8
1
12V
12V
V
IN
2
20
19
4
500mA
12V
EEIN
OUT
12
5
–12V
100mA
AUXON
LTC4241
ON
V
EEOUT
PCI
R8 10k
R9 10k
POWER
6
7
BACKPLANE
SYSTEM
CONTROLLER
FAULT
PWRGD
TIMER
CONNECTOR
C2
0.1µF
4241 F09
Figure 9. System Without 3.3V Supply
RELATED PARTS
PART NUMBER
LTC1421
DESCRIPTION
COMMENTS
2-Channel Hot Swap Controller
Hot Swap Controller in SO-8
High Voltage Hot Swap Controller
Fault Protected Hot Swap Controller
PCI-Bus Hot Swap Controller
CompactPCI Bus Hot Swap Controller
2-Channel Hot Swap Controller
CompactPCI Dual Hot Swap Controller
Dual Hot Swap Controllers
Operates from 3V to 12V and Supports –12V
System Reset Output with Programmable Delay
Operates from 9V to 80V, SO-8 Package, Latch Off/Auto Retry
Operates Up to 16.5V, Protected to 33V
LTC1422
LT1641-1/LT1641-2
LTC1642
LTC1643AL/LTC1643AL-1/LTC1643AH
3.3V, 5V and ±12V in Narrow 16-Pin SSOP Package
3.3V, 5V and ±12V, 1V Precharge, Local PCI Logic
Operates from 1.2V to 12V, Power Sequencing
3.3V and/or 5V Supplies, 1V Precharge, Local PCI Reset Logic
Operates from 2.7V to 16.5V
LTC1644
LTC1645
LTC1646
LTC1647-1/LTC1647-2/LTC1647-3
LTC4211
Single Channel, Hot Swap Controller
2.5V to 16.5V Operation, Multilevel Current Control,
MSOP Package
LTC4230
Triple Channel, Hot Swap Controller
–48V Hot Swap Controller in S0-8
–48V Hot Swap Controller in S0T-23
–48V Hot Swap Controller in MSOP
1.7V to 16.5V Operation, Multilevel Current Control
Operates from –20V to –80V, Active Current Limiting
–48V Hot Swap Controller, Active Current Limiting
Active Current Limiting With Drain Acceleration
LT4250L/LT4250H
LTC4251
LTC4252
LTC4253
–48V Hot Swap Controller and Sequencer Active Current Limiting With Drain Acceleration and Three
Sequenced Power Good Outputs
LTC4350
Hot Swappable Load Share Controller
Output Voltages from 1.5V to 12V
CompactPCI is a trademark of the PCI Industrial Computer Manufactures Group
ThinSOT is a trademark of Linear Technology Corporation
sn4241 4241f
LT/TP 0303 2K • PRINTED IN USA
16 LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
●
●
LINEAR TECHNOLOGY CORPORATION 2002
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
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