LTC4241
PCI-Bus with 3.3V Auxiliary
Hot Swap Controller
FEATURES
s
s
DESCRIPTIO
s
s
s
s
s
s
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 Swap
TM
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
APPLICATIO S
s
s
PCI-Based Servers
Computer Systems
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
supplies and an independent auxiliary controller to control
the 3.3V auxiliary supply. External N-channel transistors
are used to control the 3.3V, 5V and 3.3V auxiliary supplies
while on-chip switches control the –12V and 12V supplies.
The 3.3V, 5V and 3.3V auxiliary supplies can be ramped up
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
within tolerance. The FAULT output indicates an overcurrent
condition for any of the five supplies.
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.
TYPICAL APPLICATIO
R1
0.007Ω
Q1
IRF7413
R2
0.005Ω
Q2
IRF7413
SYSTEM
POWER
SUPPLY
R3
0.07Ω
Q3
Si2306DS
R5
10Ω
C3
10nF
R6
10Ω
9
13
14
15
3
3V
OUT
17
16
18
11
8
1
2
12
5
R8 10k
PCI
POWER
SYSTEM
CONTROLLER
RESET
6
R9 10k
7
GND
12V
IN
V
EEIN
AUXON
ON
FAULT
PWRGD
10
AUXIN AUXSENSE AUXGATE 3V
IN
3V
SENSE
GATE
5V
IN
5V
SENSE
5V
OUT
12V
500mA
–12V
100mA
BACKPLANE
CONNECTOR
C2
0.1µF
LOGIC
RESET
4241 F01
12V
OUT
LTC4241
V
EEOUT
TIMER
Figure 1. Hot Swappable PCI and 3.3V Auxiliary Supplies
sn4241 4241f
U
GND
5V
5A
R4
10Ω
3.3V
7.6A
3.3V
AUX
500mA
R7
100Ω
C1
0.047µF
20
19
4
U
U
1
LTC4241
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
TOP VIEW
12V
IN
V
EEIN
3V
OUT
TIMER
ON
FAULT
PWRGD
GND
AUXGATE
1
2
3
4
5
6
7
8
9
20 12V
OUT
19 V
EEOUT
18 5V
OUT
17 5V
IN
16 5V
SENSE
15 GATE
14 3V
SENSE
13 3V
IN
12 AUXON
11 AUXIN
Supply Voltages
12V
IN
................................................................... 14V
V
EEIN
.................................................................. –14V
AUXIN ................................................................... 7V
Input Voltage
ON ......................................................... –0.3V to 14V
AUXON .................................................. –0.3V to 14V
Output Voltages
(FAULT, PWRGD) .................................. –0.3V to 14V
Analog Voltages
TIMER, 3V
IN
, 3V
SENSE
, GATE,
5V
SENSE
, 5V
IN .............................
–0.3V to (12V
IN
+ 0.3V)
3V
OUT
, 5V
OUT
........................................ –0.3V to 14V
AUXSENSE .......................... –0.3V to (AUXIN + 0.3V)
V
EEOUT
................................................ –14V to + 0.3V
12V
OUT
.................................................. –0.3V to 14V
AUXGATE ......................... Internally Limited (Note 3)
Operating Temperature Range
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
LTC4241CGN
LTC4241IGN
AUXSENSE 10
GN PACKAGE
20-LEAD NARROW PLASTIC SSOP
T
JMAX
= 150°C,
θ
JA
= 135°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
DC ELECTRICAL CHARACTERISTICS
SYMBOL
I
DD
V
LKO
PARAMETER
V
12VIN
Supply Current
V
AUXIN
Supply Current
Undervoltage Lockout,
Low-to-High Transition
CONDITIONS
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
12VIN
= 12V, V
VEEIN
= –12V, V
3VIN
= 3.3V, V
5VIN
= 5V,
V
AUXIN
= 3.3V. (Note 2)
MIN
q
q
q
q
q
q
TYP
2.5
0.5
MAX
8
1.5
10.8
2.75
4.15
2.85
UNITS
mA
mA
V
V
V
V
mV
mV
ON = V
12VIN
AUXON = V
AUXIN
12V
IN
3V
IN
5V
IN
AUXIN
3V
IN
, 5V
IN
AUXIN
V
5VOUT
= 0V
V
5VOUT
> 4V
V
3VOUT
= 0V
V
3VOUT
> 2V
(V
5VIN
– V
5VSENSE
) = Step 0 to 100mV
(V
AUXIN
– V
AUXSENSE
) = Step 0 to 100mV
ON High, FAULT High, V
GATE
= GND
ON Low, FAULT High, V
GATE
= 5V
ON High, FAULT Low, V
GATE
= 5V
6.5
2.25
3.65
2.35
9
2.50
3.90
2.60
20
120
V
LKH
V
SENSE5(TH)
V
SENSE3(TH)
t
CB
I
GATE
Undervoltage Lockout Hysteresis
Current Limit Sense Voltage
Threshold (V
5VIN
– V
5VSENSE
)
Current Limit Sense Voltage
Threshold (V
3VIN
– V
3VSENSE
)
Circuit Breaker Trip Filter Time
GATE Pin Output Current
q
q
q
q
5.5
40
5.5
40
9
55
9
55
17
8
14.5
70
14.5
70
q
–20
5
–60
200
25
–100
35
sn4241 4241f
2
U
mV
mV
mV
mV
µs
µs
µA
µA
mA
W
U
U
W W
W
LTC4241
DC ELECTRICAL CHARACTERISTICS
SYMBOL
∆V
GATE
V
DROP
I
CL(12)
I
CL(VEE)
T
TS
V
PG(TH)
PARAMETER
External Gate Voltage
Internal Switch Voltage Drop
Current Limit
Current Limit
Thermal Shutdown Temperature
Power Good Threshold Voltage
CONDITIONS
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
12VIN
= 12V, V
VEEIN
= –12V, V
3VIN
= 3.3V, V
5VIN
= 5V,
V
AUXIN
= 3.3V. (Note 2)
MIN
q
q
q
q
q
q
q
TYP
100
200
120
MAX
200
600
250
–575
–1500
425
750
11.4
–10.8
3.0
4.78
UNITS
mV
mV
mV
mA
mA
mA
mA
°C
V
V
V
V
mV
mV
mV
(V
12VIN
– V
GATE
)
(V
12VIN
– V
12VOUT
), I
12VOUT
= 500mA
(V
EEOUT
– V
VEEIN
), I
VEEIN
= 100mA
12V
IN
= 12V, 12V
OUT
= 0V, TIMER = GND
12V
IN
= 12V, 12V
OUT
= 11V, TIMER = GND
V
EEIN
= –12V, V
EEOUT
= 0V, TIMER = GND
V
EEIN
= –12V, V
EEOUT
= –11V, TIMER = GND
V
12VOUT
Rising
V
VEEOUT
Falling
V
3VOUT
Rising
V
5VOUT
Rising
3V
OUT
5V
OUT
12V
OUT
, V
EEOUT
ON, AUXON
ON, AUXON
FAULT, PWRGD , I
OL
= 3mA
AUXON = GND
AUXON = V
AUXIN
ON = GND
ON = V
12VIN
5V
SENSE
= 5V
3V
SENSE
= 3V
5V
IN
= 5V
3V
IN
= 3V
5V
OUT
= 5V, ON = V
12VIN
3V
OUT
= 3V, ON = V
12VIN
ON = GND
ON = GND
ON = GND
ON = GND
Timer On, V
TIMER
= GND,
Timer Off, V
TIMER
= 5V,
–50
–525
50
250
10.8
–10.2
2.8
4.5
–300
–850
200
450
150
11.1
–10.5
2.9
4.65
20
30
50
q
q
q
q
V
PGH
Power Good Hysteresis
V
IL
V
IH
V
OL
I
IN
Input Low Voltage
Input High Voltage
Output Low Voltage
AUXON Pin Input Current
ON Pin Input Current
5V
SENSE
Input Current
3V
SENSE
Input Current
5V
IN
Input Current
3V
IN
Input Current
5V
OUT
Input Current
3V
OUT
Input Current
q
q
q
q
q
q
q
q
q
q
q
q
q
0.8
2
0.4
±0.08
±0.08
±0.08
±0.08
50
50
580
310
260
150
60
50
450
1600
±10
±10
±10
±10
100
100
900
550
500
350
V
V
V
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
Ω
Ω
Ω
Ω
R
DIS
5V
OUT
Discharge Impedance
3V
OUT
Discharge Impedance
12V
OUT
Discharge Impedance
V
EEOUT
Discharge Impedance
TIMER Pin Current
TIMER Threshold Voltage
(V
12VIN
– V
TIMER
)
Circuit Breaker Trip Voltage
(V
AUXIN
– V
AUXSENSE
)
AUXGATE Gate Output Current
I
TIMER
V
TIMER
V
AUXCB
I
AUXGATE
∆V
AUXGATE
q
–15
–22
45
0.9
50
–10
200
50
8
–27
µA
mA
V
mV
µA
µA
mA
V
q
q
0.5
40
–6
1.3
60
–14
AUXON High, FAULT High, V
AUXGATE
= GND
AUXON Low, FAULT High, V
AUXGATE
= 5V
AUXON High, FAULT Low, V
AUXGATE
= 10V
(V
AUXGATE
– V
AUXIN
), V
AUXIN
= 3.3V
q
External AUXGATE Gate Voltage
q
5
11
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
TYPICAL PERFOR A CE CHARACTERISTICS
3.3V and 5V Current
Foldback Profile
12
10
3V
OUT
5V
OUT
OUTPUT CURRENT (mA)
OUTPUT CURRENT (A)
800
700
600
500
400
300
200
100
0
OUTPUT CURRENT (mA)
8
6
4
2
0
3V
IN
= 3.3V
5V
IN
= 5V
R
SENSE
= 0.005Ω
0.5
1.5
2.5
3.5
4.5
OUTPUT VOLTAGE (V)
5.5
4241 • G01
5V
IN
Current Limit Voltage
vs Temperature
70
CURRENT LIMIT VOLTAGE (mV)
70
CURRENT LIMIT VOLTAGE (mV)
60
50
40
30
20
10
0
–75 –50 –25
5V
OUT
= 5V
CURRENT LIMIT (mA)
5V
OUT
= 0V
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G04
V
EEIN
Current Limit
vs Temperature
600
55
CIRCUIT BREAKER TRIP VOLTAGE (mV)
GATE OUTPUT SOURCE CURRENT (µA)
500
V
EEOUT
= –11V
CURRENT LIMIT (mA)
400
300
200
V
EEOUT
= 0V
100
0
–75 –50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G07
4
U W
12V Current Foldback Profile
1100
1000
900
12V
IN
= 12V
1100
1000
900
800
700
600
500
400
300
200
100
0
1
2
3 4 5 6 7 8 9 10 11 12
OUTPUT VOLTAGE (V)
4241 • G02
–12V Current Foldback Profile
V
EEIN
= –12V
0
0 –1 –2 –3 –4 –5 –6 –7 –8 –9 –10 –11 –12
OUTPUT VOLTAGE (V)
4241 • G03
3V
IN
Current Limit Voltage
vs Temperature
1200
3V
OUT
= 3.3V
1000
800
600
400
200
60
50
40
30
20
10
0
–75 –50 –25
3V
OUT
= 0V
12V
IN
Current Limit
vs Temperature
12V
OUT
= 11V
12V
OUT
= 0V
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G05
0
–75 –50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G06
(V
AUXIN
– V
AUXSENSE
)
Circuit Breaker Trip Voltage
vs Temperature
90
80
70
54
53
52
51
50
49
48
47
46
45
–75 –50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G08
GATE, AUXGATE Output Source
Current vs Temperature
12.5
AUXGATE OUTPUT SOURCE CURRENT (µA)
12.0
11.5
GATE
11.0
10.5
AUXGATE
10.0
9.5
9.0
8.5
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G09
60
50
40
30
20
10
–75 –50 –25
sn4241 4241f
LTC4241
TYPICAL PERFOR A CE CHARACTERISTICS
GATE, AUXGATE Output Sink
Current vs Temperature
350
300
GATE
250
200
150
100
50
–75 –50 –25
AUXGATE
FAST PULL-DOWN CURRENT (mA)
80
70
OUTPUT SINK CURRENT (µA)
(V
AUXGATE
– V
AUXIN
) (V)
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G10
AUXGATE Voltage vs Temperature
11.75
INTERNAL SWITCH VOLTAGE DROP (mV)
11.60
300
275
250
225
200
175
150
125
INTERNAL SWITCH VOLTAGE DROP (mV)
AUXGATE VOLTAGE (V)
11.45
11.30
11.15
11.00
10.85
10.70
–75 –50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G13
Power Good Threshold Voltage
vs Temperature (12V
OUT
)
11.20
4.68
POWER GOOD THRESHOLD VOLTAGE (V)
POWER GOOD THRESHOLD VOLTAGE (V)
11.15
11.10
11.05
11.00
10.95
10.90
–75 –50 –25
4.67
4.66
4.65
4.64
4.63
4.62
4.61
4.60
–75 –50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G17
POWER GOOD THRESHOLD VOLTAGE (V)
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G16
U W
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
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G11
(V
AUXGATE
– V
AUXIN
)
vs Temperature
AUXIN = 3.3V
60
50
40
GATE
30
20
10
0
–75 –50 –25
AUXGATE
7.75
–75 –50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G12
12V Internal Switch Voltage Drop
vs Temperature
325
I
12VOUT
= 500mA
200
180
160
140
120
100
80
60
V
EE
Internal Switch Voltage Drop
vs Temperature
I
VEEIN
= 100mA
100
–75 –50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G14
40
–75 –50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G15
Power Good Threshold Voltage
vs Temperature (5V
OUT
)
2.915
2.910
2.905
2.900
2.895
2.890
2.885
2.880
Power Good Threshold Voltage
vs Temperature (3V
OUT
)
2.875
–75 –50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
4241 • G18
sn4241 4241f
5
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