2926.indd
LTC2926
1
2926f
15.0k
9.53k
0.1
F
2926 TA01
LTC2926
RAMP
FB2
OUT
SENSE
RAMPBUF
TRACK1
TRACK2
PGTMR
GND
V
CC
V
CC
D1
15.0k
4.02k
FAULT
10k
1
F
SGATE1
10
SGATE2
10
100
V
CC
STATUS
IRF7413Z
IRF7413Z
ON
10k
1.8V MODULE
1.8V
SLAVE1
OUT
SENSE
D2
100
3.3V MODULE
3.3V
SLAVE2
S2
15.0k
4.02k
STATUS/PGI
FB1
S1
15.0k
9.53k
FAULT
ON/OFF
0.1
F
MGATE
MOSFET-Controlled
Power Supply Tracker
The LTC2926 provides a simple solution for tracking and
sequencing up to three power supply rails. An N-channel
MOSFET and a few resistors per channel confi gure the
load voltages to ramp up and down together, with voltage
offsets, with time delays or with different ramp rates.
Automatic remote sense switching compensates for voltage
drops across the MOSFETs. The LTC2926 provides two
integrated switches as well as a signal to control optional
additional external N-channel MOSFET sense switches.
The LTC2926 includes I/O signals for communication with
other devices. The status output asserts after tracking and
sequencing have completed. A low voltage on the power
good input after an adjustable timeout period causes load
disconnect. A low voltage on the fault I/O causes immedi-
ate load disconnect. Until it is reset, a fault latch prevents
tracking and keeps the loads disconnected.
V
CORE
and V
I/O
Supply Tracking
Microprocessor, DSP and FPGA Supplies
Servers
Communications Systems
Flexible Power Supply Tracking and Sequencing
Adjustable Ramp Rates, Offsets and Time Delays
Controls Three Supplies with Series MOSFETs
Integrated Remote Sense Switching
FAULT Input/Output
STATUS Output/Power Good Input
Available in 20-Lead Narrow SSOP and 20-Lead QFN
(4mm 5mm) Packages
APPLICATIO S
U
FEATURES
TYPICAL APPLICATIO
U
DESCRIPTIO
U
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
*Protected by U.S. Patents including 6897717.
2926 TA01b
500mV/DIV
3.3V SLAVE2
1.8V SLAVE1
5ms/DIV
2926 TA01c
500mV/DIV
3.3V SLAVE2
1.8V SLAVE1
5ms/DIV
LTC2926
2
2926f
Supply Voltage (V
CC
) ................................. 0.3V to 10V
Input Voltages
ON ......................................................... 0.3V to 10V
RAMP .............................................0.3V to V
CC
+ 1V
TRACK1, TRACK2 ........................0.3V to V
CC
+ 0.3V
PGTMR ........................................0.3V to V
CC
+ 0.3V
Input/Output Voltages
FAULT .................................................... 0.3V to 10V
STATUS/PGI (Note 3) .......................... 0.3V to 11.5V
Output Voltages
RAMPBUF ....................................0.3V to V
CC
+ 0.3V
FB1, FB2, D1, S1, D2, S2 ....................... 0.3V to 10V
MGATE, RSGATE (Note 3) ................... 0.3V to 11.5V
SGATE1, SGATE2 (Note 3) .................. 0.3V to 11.5V
(Notes 1, 2)
RMS Currents
TRACK1, TRACK2 ................................................5mA
FB1, FB2 ..............................................................5mA
D1, S1, D2, S2 ...................................................30mA
Operating Temperature
LTC2926C ................................................ 0C to 70C
LTC2926I ............................................. 40C to 85C
Storage Temperature Range
GN Package ....................................... 65C to 150C
UFD Package ...................................... 65C to 125C
Lead Temperature (Soldering, 10 sec)
GN Package ...................................................... 300C
ABSOLUTE AXI U
RATI GS
W
W
W
U
PACKAGE/ORDER I FOR ATIO
U
U
W
GN PACKAGE
20-LEAD PLASTIC SSOP
1
2
3
4
5
6
7
8
9
10
TOP VIEW
20
19
18
17
16
15
14
13
12
11
V
CC
TRACK1
FB1
S1
SGATE1
D1
ON
PGTMR
FAULT
GND
RAMPBUF
TRACK2
FB2
S2
SGATE2
D2
STATUS/PGI
RSGATE
MGATE
RAMP
T
JMAX
= 125C,
JA
= 85C/W
20 19 18 17
7
8
TOP VIEW
UFD PACKAGE
20-LEAD (4mm
5mm) PLASTIC QFN
9
10
6
5
4
3
2
1
11
12
21
13
14
15
16
FB1
S1
SGATE1
D1
ON
PGTMR
FB2
S2
SGATE2
D2
STATUS/PGI
RSGATE
TRACK1
V
CC
RAMPBUF
TRACK2
FAULT
GND
RAMP
MGATE
EXPOSED PAD (PIN 21) IS GND
PCB CONNECTION OPTIONAL
T
JMAX
= 125C,
JA
= 43C/W
ORDER PART NUMBER
ORDER PART NUMBER
UFD PART MARKING*
LTC2926CGN
LTC2926IGN
LTC2926CUFD
LTC2926IUFD
2926
2926
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 specifi ed with wider operating temperature ranges.
LTC2926
3
2926f
The
denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25C. V
CC
= 3.3V unless otherwise specifi ed.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage
V
CC
Input Supply Voltage
Operating Range
2.9
3.3
5.5
V
I
CC
Input Supply Current
I
TRACKn
= 0mA, I
FBn
= 0mA,
I
RAMPBUF
= 0mA
1.5
2.5
3.5
mA
I
TRACKn
= 1mA, I
FBn
= 1mA,
I
RAMPBUF
= 3mA
8.5
9.5
10.5
mA
V
CC(UVLO)
Input Supply Undervoltage Lockout
V
CC
Rising
2.2
2.4
2.6
V
V
CC(UVLO)
Input Supply Undervoltage Lockout
Hysteresis
15
50
75
mV
Control and I/O
V
ON(TH)
ON Pin Threshold Voltage
V
ON
Rising
1.20
1.23
1.26
V
V
ON(TH)
ON Pin Threshold Voltage Hysteresis
40
75
110
mV
I
ON
ON Pin Input Current
V
ON
= 1.2V, V
CC
= 5.5V
0
100
nA
V
ON(CLR)
ON Pin Fault Clear Threshold Voltage
V
ON
Falling
0.465
0.500
0.535
V
V
ON(ARM)
ON Pin Fault Arm Threshold Voltage
V
ON
Rising
0.565
0.600
0.635
V
V
FAULT(TH)
FAULT Pin Input Threshold Voltage
V
FAULT
Falling
0.465
0.500
0.535
V
I
FAULT(UP)
FAULT Pin Pull-up Current
Fault Latch Clear, V
FAULT
= 1.5V
3.0
8.5
13
A
V
FAULT(OL)
FAULT Pin Output Low Voltage
Fault Latch Set, I
FAULT
= 5mA, V
CC
= 2.7V
100
400
mV
V
FAULT(OH)
FAULT Pin Output High Voltage
(V
CC
V
FAULT
)
Fault Latch Clear, I
FAULT
= 1A
300
550
900
mV
V
PGI(TH)
STATUS/PGI Pin Input Threshold
Voltage
V
STATUS/PGI
Rising
1.10
1.23
1.36
V
V
PGI(TH)
STATUS/PGI Pin Input Threshold
Voltage Hysteresis
30
75
150
mV
I
PGI(UP)
STATUS/PGI Pin Pull-Up Current
STATUS/PGI On, V
STATUS/PGI
= 1.5V
7
10
13
A
V
STATUS(OL)
STATUS/PGI Pin Output Low Voltage
V
ON
Low, I
STATUS/PGI
= 5mA, V
CC
= 2.7V
200
400
mV
V
STATUS(OH)
STATUS/PGI Pin Output High Voltage
(V
STATUS/PGI
V
CC
)
I
STATUS/PGI
= 1A
5.0
5.5
6.0
V
V
PGTMR(TH)
PGTMR Pin Threshold Voltage
V
PGTMR
Rising
1.10
1.23
1.36
V
I
PGTMR(UP)
PGTMR Pin Pull-Up Current
ON High, V
PGTMR
= 1V
5.0
3.0
8.5
8.5
13
13
A
A
I
PGTMR(DN)
PGTMR Pin Pull-Down Current
ON Low, V
PGTMR
= 0.1V, V
CC
= 2.7V
0.5
4
10
mA
V
PGTMR(CLR)
PGTMR Pin Clear Threshold Voltage
V
PGTMR
Falling
50
100
150
mV
Ramp Buffer
I
RAMP(IN)
RAMP Pin Input Current
0V < V
RAMP
< 5.5V, V
CC
= 5.5V
0
1
A
V
RAMPBUF(OS)
Ramp Buffer Offset Voltage
V
RAMP
= 1/2 V
CC
, I
RAMPBUF
= 0mA
0
10
mV
V
RAMPBUF(OL)
RAMPBUF Pin Output Low Voltage
I
RAMPBUF
= 3mA
32
60
mV
V
RAMPBUF(OH)
RAMPBUF Pin Output High Voltage
(V
CC
V
RAMPBUF
)
I
RAMPBUF
= 3mA
60
80
mV
ELECTRICAL CHARACTERISTICS
LTC2926
4
2926f
The
denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25C. V
CC
= 3.3V unless otherwise specifi ed.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: All currents into the device pins are positive; all currents out of
the device pins are negative. All voltages are referenced to ground unless
otherwise specifi ed.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Tracking Channels
I
ERROR(%)
I
FBn
to I
TRACKn
Current Mismatch
(I
FBn
I
TRACKn
)/I
TRACKn
100%
I
TRACKn
= 10A
I
TRACKn
= 1mA
0
0
3
3
%
%
V
TRACK
TRACK Pins Voltage
I
TRACKn
= 10A
I
TRACKn
= 1mA
0.776
0.776
0.800
0.800
0.824
0.824
V
V
V
FB(REF)
FB Pins Internal Reference Voltage
V
TRACKn
= V
CC
, I
FBn
= 0mA
0.784
0.800
0.816
V
I
FB(LEAK)
FB Pins Leakage Current
V
FBn
= 0.8V, V
CC
= 5.5V
0
10
nA
V
FB(CLAMP)
FB Pins Clamp Voltage
1mA < I
FBn
< 1A
1.7
2.0
2.4
V
Master Ramp and Supply
V
MGATE
MGATE Pin External N-Channel Gate
Drive (V
MGATE
V
CC
)
I
MGATE
= 1A
5.0
5.5
6.0
V
I
MGATE(UP)
MGATE Pin Pull-Up Current
Fault Latch Clear, V
ON
High, V
MGATE
= 3.3V
7
10
13
A
I
MGATE(DN)
MGATE Pin Pull-Down Current
Fault Latch Clear, V
ON
Low, V
MGATE
= 3.3V
7
10
13
A
I
MGATE(FAULT)
MGATE Pin Fault Pull-Down Current
Fault Latch Set, V
ON
High, V
MGATE
= 5.5V,
V
CC
= 5.5V
5
20
50
mA
Slave Supplies
V
SGATE
SGATE Pins External N-Channel Gate
Drive (V
SGATEn
V
CC
)
I
SGATEn
= 1A, V
FBn
= 0.75V
5.0
5.5
6.0
V
I
SGATE(UP)
SGATE Pins Pull-Up Current
Fault Latch Clear, V
FBn
= V
FB(REF)
15mV,
V
SGATEn
= 3.3V
6
10
13
A
I
SGATE(DN)
SGATE Pins Pull-Down Current
Fault Latch Clear, V
FBn
= V
FB(REF)
+ 15mV,
V
SGATEn
= 3.3V
6
10
13
A
I
SGATE(UPFST)
SGATE Pins Fast Pull-Up Current
Fault Latch Clear, V
FBn
= 0V, V
SGATEn
= 3.3V
21
30
39
A
I
SGATE(DNFST)
SGATE Pins Fast Pull-Down Current
Fault Latch Clear, V
FBn
= 1V, V
SGATEn
= 3.3V
21
30
39
A
I
SGATE(FAULT)
SGATE Pins Fault Pull-Down Current
Fault Latch Set, V
ON
High, V
SGATEn
= 5.5V,
V
CC
= 5.5V
5
20
50
mA
Remote Sense Switches
V
RSGATE
RSGATE Pin External N-Channel Gate
Drive (V
RSGATE
V
CC
)
I
RSGATE
= 1A
5.0
5.5
6.0
V
I
RSGATE(UP)
RSGATE Pin Pull-Up Current
Fault Latch Clear, Switches On, V
RSGATE
= 0V
7
10
13
A
I
RSGATE(DN)
RSGATE Pin Pull-Down Current
Fault Latch Clear, Switches Off,
V
RSGATE
= 3.3V
7
10
13
A
I
RSGATE(FAULT)
RSGATE Pin Fault Pull-Down Current
Fault Latch Set, Switches Off,
V
RSGATE
= 5.5V, V
CC
= 5.5V
5
20
50
mA
R
SW(ON)
Remote Sense Switch On-Resistance
Switches On, V
Dn
= V
CC
+ 0.3V, I
Sn
= 10mA
2
10
Note 3: The MGATE, SGATE1, SGATE2, RSGATE and STATUS/PGI pins are
internally limited to a minimum of 11.5V. Driving these pins to voltages
beyond the clamp level may damage the part.
ELECTRICAL CHARACTERISTICS
LTC2926
5
2926f
TEMPERATURE (
C)
I
MGATE(PD)
, I
RSGATE(PD)
(mA)
2926 G08
V
CC
= 5.5V
V
CC
= 3.3V
V
CC
= 2.9V
50
25
75
25
0
50
100
30
25
20
15
10
0
5
MGATE, RSGATE PINS
FAULT LATCH SET
V
CC
(V)
2.5
I
GATE(PD)
(mA)
6.0
2926 G07
3.0
3.5
4.0
4.5
5.0
5.5
30
25
20
15
10
0
5
FAULT LATCH SET
MGATE, RSGATE, SGATE1, SGATE2 PINS
I
LOAD
(
A)
GATE DRIVE (V)
6
0
5
4
3
2
1
2926 G06
0
15
25
5
10
20
35
30
MGATE, RSGATE,
SGATE1, SGATE2 PINS
PULL-UP MODE
SGATE1,
SGATE2 PINS
FAST PULL-UP
MODE
GATE DRIVE = V
PIN
V
CC
V
CC
(V)
2.5
GATE DRIVE (V)
6.0
2926 G05
3.0
3.5
4.0
4.5
5.0
5.5
6.0
5.8
5.6
5.4
5.2
5.0
GATE DRIVE = V
PIN
V
CC
MGATE, RSGATE, SGATE1, SGATE2 PINS
I
GATE
= 1
A
V
CC
(V)
2.5
I
CC
(mA)
12
10
8
6
4
2
0
4.0
5.0
2926 G01
3.0
3.5
4.5
5.5
6.0
I
RAMPBUF
= 3mA
I
TRACKn
= 1mA
I
FBn
= 1mA
I
RAMPBUF
= 0mA
I
TRACKn
= 0mA
I
FBn
= 0mA
TEMPERATURE (
C)
I
CC
(mA)
12
10
8
6
4
2
0
2926 G02
I
RAMPBUF
= 3mA
I
TRACKn
= 1mA
I
FBn
= 1mA
I
RAMPBUF
= 0mA
I
TRACKn
= 0mA
I
FBn
= 0mA
50
25
75
25
0
50
100
TEMPERATURE (
C)
V
TRACK
(V)
0.812
0.808
0.804
0.800
0.796
0.792
0.788
2926 G03
I
TRACK
= 10
A
I
TRACK
= 1mA
50
25
75
25
0
50
100
TEMPERATURE (
C)
I
PGTMR(PU)
(
A)
12
10
8
6
4
2
0
2926 G04
V
PGTMR
= 1V
50
25
75
25
0
50
100
Supply Current vs Supply Voltage
Supply Current vs Temperature
Track Pin Voltage vs Temperature
PGTMR Pin Pull-Up Current vs
Temperature
Gate Drive Voltages vs
Supply Voltage
Gate Drive Voltages vs
Load Current
MGATE, RSGATE Fault Pull-Down
Currents vs Temperature
SGATE Fault Pull-Down Current vs
Temperature
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
Gate Fault Pull-Down Currents vs
Supply Voltage
TEMPERATURE (
C)
I
SGATE(PD)
(mA)
2926 G09
V
CC
= 5.5V
V
CC
= 3.3V
V
CC
= 2.9V
50
25
75
25
0
50
100
30
25
20
15
10
0
5
SGATE1, SGATE2 PINS
FAULT LATCH SET
Specifi cations are at T
A
= 25C, V
CC
= 3.3V
unless otherwise specifi ed.
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