be safely inserted and removed from a live backplane in
multiple supply systems such as CompactPCI and PCI
Express. Using four external N-channel pass transistors,
the board supply voltages can be ramped up at an adjust-
able rate and in any desired sequence. An I
2
C interface and
onboard ADC allow monitoring of board current, voltage
and fault status for each supply.
The device features adjustable dI/dt controlled soft start
and foldback limited inrush current. A dual-level timed
circuit breaker and fast current limit protect each supply
against overcurrent faults. A power good input with timeout
allows a downstream supply monitor to disconnect the
board supplies. The device can be configured to function
without a –12V supply or with an extra 3.3V supply instead
of a 5V supply.
The controller has additional features to interrupt the host
when a fault has occurred, notify when output power is
good, detect insertion of a load card and power-up in
either the on or off state.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Allows Safe Insertion into Live CompactPCI
TM
or
PCI Express
TM
Backplane
8-Bit ADC Monitors Current and Voltage
I
2
C
TM
/SMBus Interface
dI/dt Controlled Soft Start
Simultaneous or Sequenced Turn-On
±20V Absolute Maximum Rating for ±12V Supplies
No External Gate Capacitor Required
Dual-Level Circuit Breaker and Current Limit
Bus Precharge Output
Power Good Input with Timeout
Optional Latchoff or Autoretry After Faults
Alerts Host After Faults
Integrated LOCAL_PCI_RST# Logic
36-Pin SSOP and 38-Pin (5mm
×
7mm) QFN
Packages
APPLICATIO S
■
■
Live Board Insertion
CompactPCI, CompactPCI Express, CompactTCA,
PCI Express Systems
TYPICAL APPLICATIO
BACKPLANE
CONNECTOR
CARD
CONNECTOR
CompactPCI Application
Sequenced Turn-On Waveform
5V
OUT
12V
OUT
BD_SEL#
10V/DIV
12V
OUT
OUTPUT
VOLTAGE
5V/DIV
V
EEOUT
5V
OUT
3V
OUT
12V
IN
12V
SENSE
12V
GATE
12V
OUT
5V
IN
5V
SENSE
5V
GATE
5V
OUT
BD_SEL#
ON
HEALTHY#
SDA
SCL
ALERT#
PCI_RST#
GND
PRECHARGE
LTC4245
LOCAL_PCI_RESET#
PGI
SUPPLY
MONITOR
RESET
BOARD
RESET
TO BUS
LOCAL_PCI_RST#
5V/DIV
TIME (50ms/DIV)
–12V
OUT
4245 TA01b
3V
OUT
V
EEIN
V
EESENSE
V
EEGATE
V
EEOUT
3V
IN
3V
SENSE
3V
GATE
3.3V
OUT
U
U
U
4245fa
1
LTC4245
ABSOLUTE
(Notes 1, 2)
AXI U RATI GS
V
EEGATE
– V
EEIN
(Note 4) .......................... –0.3V to 5V
12V
SENSE
........... –0.3V or 12V
IN
– 6V to 12V
IN
+ 0.3V
n
SENSE
...........................................–0.3V to
n
IN
+ 0.3V
V
EESENSE
..................................... V
EEIN
– 0.3V to 0.3V
12V
OUT
– 12V
GATE
(Note 4)...................... –5V to 0.3V
n
OUT
–
n
GATE
(Note 4) .............................. –5V to 0.3V
V
EEOUT
(Note 5)...................................... –20V to 0.3V
PRECHARGE .............................. –0.3V to 3V
IN
+ 0.3V
Operating Temperature Range
LTC4245C ................................................ 0°C to 70°C
LTC4245I ............................................. –40°C to 85°C
Storage Temperature Range
G Package .......................................... –65°C to 150°C
UHF Package...................................... –65°C to 125°C
Lead Temperature (Soldering, 10 sec)
G Package ......................................................... 300°C
Supply Voltages
12V
IN
..................................................... –0.3V to 20V
5V
IN
, 3V
IN
.............................................. –0.3V to 10V
V
EEIN
...................................................... –20V to 0.3V
INTV
CC
.................................................. –0.3V to 6.5V
Input Voltages
BD_SEL#, ON, PGI ................................. –0.3V to 12V
ADR0-3, CFG, SS, TIMER ...... –0.3V to INTV
CC
+ 0.3V
PCI_RST#, SCL, SDA ............................ –0.3V to 6.5V
Output Voltages
ALERT#, GPIO1-3, HEALTHY#,
LOCAL_PCI_RST# ................................ –0.3V to 6.5V
Analog Voltages (n is 5V, 3V)
12V
GATE
................................................. –0.3V to 25V
n
GATE
(Note 3)............... –0.3V to 12V
IN
+ 0.3V or 14V
PACKAGE/ORDER I FOR ATIO
TOP VIEW
HEALTHY#
TIMER
ON
SS
12V
IN
12V
SENSE
12V
GATE
12V
OUT
GND
1
2
3
4
5
6
7
8
9
36 5V
IN
35 5V
SENSE
34 5V
GATE
33 5V
OUT
32 ADR3
31 ADR2
30 ADR1
29 ADR0
28 INTV
CC
27 GPIO1
26 PGI
25 PCI_RST#
24 LOCAL_PCI_RST#
23 PRECHARGE
22 3V
IN
21 3V
SENSE
20 3V
GATE
19 3V
OUT
HEALTHY#
5V
SENSE
5V
GATE
TIMER
38 37 36 35 34 33 32
SS 1
12V
IN
2
12V
SENSE
3
12V
GATE
4
12V
OUT
5
GND 6
BD_SEL# 7
CFG 8
SDA 9
SCL 10
ALERT# 11
V
EESENSE
12
13 14 15 16 17 18 19
3V
OUT
V
EEIN
3V
GATE
V
EEOUT
3V
SENSE
V
EEGATE
3V
IN
39
31 ADR3
30 ADR2
29 ADR1
28 ADR0
27 INTV
CC
26 GPIO3
25 GPIO2
24 GPIO1
23 PGI
22 PCI_RST#
21 LOCAL_PCI_RST#
20 PRECHARGE
BD_SEL# 10
CFG 11
SDA 12
SCL 13
ALERT# 14
V
EESENSE
15
V
EEIN
16
V
EEGATE
17
V
EEOUT
18
G PACKAGE
36-LEAD PLASTIC SSOP
UHF PACKAGE
38-LEAD (5mm
×
7mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 95°C/W
T
JMAX
= 125°C,
θ
JA
= 34°C/W
EXPOSED PAD (PIN 39) PCB GND CONNECTION OPTIONAL
ORDER PART NUMBER
LTC4245CG
LTC4245IG
ORDER PART NUMBER
LTC4245CUHF
LTC4245IUHF
UHF PART MARKING*
4245
4245
Order Options
Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking:
http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
4245fa
2
5V
OUT
5V
IN
ON
U
U
W
W W
U
W
TOP VIEW
LTC4245
ELECTRICAL CHARACTERISTICS
SYMBOL
Supplies
I
DD
Input Supply Current
12V
IN
5V
IN
3V
IN
, PRECHARGE Open
V
EEIN
12V
IN
5V
IN
, V
CFG
= 0V, Open
5V
IN
When V
CFG
= V
CC
, 3V
IN
V
EEIN
, V
CFG
= 0V
V
CC
Falling
●
●
●
●
●
●
●
●
●
●
The
●
denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. V
12VIN
= 12V, V
5VIN
= 5V, V
3VIN
= 3.3V, V
VEEIN
= –12V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
3
0.5
0.6
–0.5
10.2
4.25
2.7
–10.2
3.4
5
10.5
4.38
2.8
–10.5
3.8
5.5
MAX
5
1
1
–1
10.8
4.5
2.9
–10.8
4.2
6
UNITS
mA
mA
mA
mA
V
V
V
V
V
V
V
UVL
Supply Undervoltage Lockout
V
CC
Current Limit
ΔV
SNS(CB)
Internal Regulator Voltage
Circuit Breaker Trip Sense Voltage
(V
12VIN
– V
12VSENSE
)
(V
5VIN
– V
5VSENSE
)
(V
3VIN
– V
3VSENSE
)
(V
VEESENSE
– V
VEEIN
)
Active Current Limit Sense Voltage
(V
12VIN
– V
12VSENSE
)
(V
5VIN
– V
5VSENSE
)
(V
3VIN
– V
3VSENSE
)
(V
VEESENSE
– V
VEEIN
)
Foldback Current Limit Sense Voltage
(V
12VIN
– V
12VSENSE
)
(V
5VIN
– V
5VSENSE
)
(V
3VIN
– V
3VSENSE
)
(V
VEESENSE
– V
VEEIN
)
After Start-Up
●
●
●
●
45
22.5
22.5
40
130
60
60
130
10
40
4
22
4
22
11
40
5
–16
0.9
1.7
125
155
32
1.21
70
–7
50
25
25
50
150
75
75
150
15
50
7.5
25
7.5
25
16
50
6.2
–20
1.3
3.5
250
310
65
1.235
120
–10
55
27.5
27.5
60
170
90
90
170
20
60
11
29
11
29
21
60
7.5
–24
1.7
5.3
375
465
98
1.26
170
–16
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
V
μA
mA
mA
mA
mA
mA
V
mV
µA
ΔV
SNS(ACL)
After Start-Up
●
●
●
●
ΔV
SNS(FBL)
,
ΔV
SNS(FBH)
Start-Up, V
TIMER
= 0V
V
12VOUT
= 0V
V
12VOUT
= 12V
V
5VOUT
= 0V
V
5VOUT
= 5V
V
3VOUT
= 0V
V
3VOUT
= 3.3V
V
VEEOUT
= 0V
V
VEEOUT
= –12V
Gate to Source
Gate Drive On,
ΔV
GATE
= 0V
Gate Drive Off,
ΔV
GATE
= 5V
V
OUT
= V
IN
V
VEEGATE
= –7V
Fast Turn Off,
ΔV
GATE
= 5V
V
12VGATE
= 17V, V
5VGATE
= 10V
V
3VGATE
= 8.3V
V
VEEGATE
= –7V
V
ON
Rising, V
BD_SEL#
Rising
V
BD_SEL#
= 0V
●
●
●
●
●
●
●
●
Gate Drive
ΔV
GATE
I
GATE(UP)
I
GATE(DN)
Gate Drive
Gate Pull-Up Current
Gate Pull-Down Current
12V
GATE
, 5V
GATE
, 3V
GATE
,
V
EEGATE
Gate Fast Pull-Down Current
12V
GATE
, 5V
GATE
3V
GATE
V
EEGATE
ON, BD_SEL# Pin Threshold Voltage
BD_SEL# Pull-Up Current
●
●
●
●
●
●
●
I
GATE(FST)
Input/Output Pins
V
ON, BD_SEL#(TH)
I
BD_SEL#(UP)
●
●
●
ΔV
ON, BD_SEL#(HYST)
ON, BD_SEL# Pin Hysteresis
4245fa
3
LTC4245
ELECTRICAL CHARACTERISTICS
SYMBOL
V
PB(TH)
PARAMETER
Power Bad Threshold Voltage
The
●
denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. V
12VIN
= 12V, V
5VIN
= 5V, V
3VIN
= 3.3V, V
VEEIN
= –12V, unless otherwise noted.
CONDITIONS
12V
OUT
5V
OUT
, V
CFG
= 0V, Open
5V
OUT
When V
CFG
= V
CC
, 3V
OUT
V
EEOUT
, V
CFG
= 0V
PGI, PCI_RST#, GPIOn
SDA, SCL
ON, PGI, PCI_RST#, V = 1.2V
SDA, SCL, ALERT#, GPIOn, HEALTHY#,
LOCAL_PCI_RST#, V = 6V
SDA, ALERT#, I = 5mA; GPIOn,
HEALTHY#, LOCAL_PCI_RST#, I = 3mA
●
●
●
●
●
●
●
MIN
10.8
4.5
2.8
–10.8
0.8
1.6
TYP
11.1
4.63
2.9
–11.1
1.0
1.8
0
MAX
11.4
4.75
3.0
–11.4
1.2
2.0
±1
UNITS
V
V
V
V
V
V
μA
V
IN(TH)
I
IN
Logic Input Threshold
Pin Input Current
V
OL
V
TRI(H)
V
TRI(L)
I
TRI(IN,HL)
I
TRI(IN,Z)
I
ADR01(IN)
I
SENSE
Output Low Voltage
ADR2, ADR3, CFG Input High Threshold
ADRn, CFG Input Low Threshold
ADR2, ADR3, CFG High, Low Input
Current
ADR2, ADR3, CFG High Z Input Current
ADR0, ADR1 Input Current
Sense Pin Input Current
12V
SENSE
, 5V
SENSE
, 3V
SENSE
V
EESENSE
OUT Pin Input Current
●
●
●
0.2
V
CC
–0.8
0.2
0.4
V
V
V
μA
μA
V
CC
–0.4 V
CC
–0.2
0.4
0.8
±80
V = 0V, V
CC
V = 0.8V, V
CC
–0.8V
V
ADR0
, V
ADR1
= 0V, V
CC
After Start-Up
V
SENSE
= V
IN
V
VEESENSE
= –12V
V
12VOUT
= 12V, V
ON
= 2V
V
5VOUT
= 5V, V
ON
= 2V
V
3VOUT
= 3.3V, V
ON
= 2V
V
VEEOUT
= –12V, V
ON
= 2V
V
12VOUT
= 6V, V
ON
= 0V
V
5VOUT
= 3V, V
ON
= 0V
V
3VOUT
= 2V, V
ON
= 0V
V
VEEOUT
= –6V, V
ON
= 0V
V
VEEOUT
= 0V
I
PRECHARGE
= Open, –70mA (Note 6)
V
TIMER
Rising
V
TIMER
Falling
During Start-Up, V
TIMER
= 0V
During PGI Timeout, V
TIMER
= 0V
During Auto-Retry, V
TIMER
= 0V
(I
TIMER(RTRY)
/I
TIMER(START)
)
((V
TIMER(H)
– V
TIMER(L)
)/I
TIMER(START)
)
Fast Ramp, V
SS
= 0V
Slow Ramp, V
SS
= 2V
V
TIMER
= 1.2V, V
SS
= 1.2V
12V
IN
, V
EEIN
5V
IN
, 3V
IN
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
±10
–30
0.3
–30
200
275
75
–200
650
125
130
1300
0.95
2.5
0.1
–80
–8
–1.5
1.6
20
–16
–1.5
1000
180
190
1800
–36
1
2.56
0.23
–100
–10
–2
2
23.3
–20
–2
225
46
23
1
1
–45
280
390
105
–280
1800
325
340
3200
–54
1.05
2.62
0.4
–120
–12
–2.5
2.7
26
–24
–2.5
400
μA
μA
μA
μA
μA
μA
μA
Ω
Ω
Ω
Ω
μA
V
V
V
μA
μA
μA
%
ms/μF
μA
μA
Ω
mV/V
mV/V
I
OUT(ON)
R
OUT(DIS)
OUT Pin Discharge Resistance
I
VEEOUT(UP)
V
PXG
Timer, Soft-Start
V
TIMER(H)
V
TIMER(L)
I
TIMER
V
EEOUT
Pull-Up Current
PRECHARGE Voltage
TIMER Pin High Threshold
TIMER Pin Low Threshold
TIMER Pin Pull-Up Current
●
●
●
●
●
●
●
●
●
●
K
TMRATIO
K
TMCAP
I
SS
R
TS(DIS)
G
SS
TIMER Pin Current Ratio
Start-Up Time per TIMER Capacitance
SS Pin Pull-Up Current
TIMER, SS Discharge Resistance
Gain from SS Pin to Foldback Current
Limit (ΔV
SNS(FB)
/ΔV
SS
)
4245fa
4
LTC4245
ELECTRICAL CHARACTERISTICS
SYMBOL
ADC
RES
V
FS
Resolution (No Missing Codes)
Full-Scale Voltage (V
FS
= 255LSB)
12V
IN
, 12V
OUT
12V
IN
– 12V
SENSE
, V
EESENSE
– V
EEIN
5V
IN
, 5V
OUT
5V
IN
– 5V
SENSE
, 3V
IN
– 3V
SENSE
3V
IN
, 3V
OUT
V
EEIN
, V
EEOUT
GPIO
INL
OE
Integral Nonlinearity
Offset Error
ΔV
SENSE
(Note 8)
Other 9 Channels
ΔV
SENSE
(Note 6)
V
EEIN
, V
EEOUT
Other 7 Channels
(Note 7)
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
The
●
denotes the specifications which apply over the full operating temperature
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