LTC2926
MOSFET-Controlled
Power Supply Tracker
FEATURES DESCRIPTIO
Flexible Power Supply Tracking and Sequencing The LTC2926 provides a simple solution for tracking and
Adjustable Ramp Rates, Offsets and Time Delays sequencing up to three power supply rails. An N-channel
Controls Three Supplies with Series MOSFETs MOSFET and a few resistors per channel con gure the
Integrated Remote Sense Switching load voltages to ramp up and down together, with voltage
FAULT Input/Output offsets, with time delays or with different ramp rates.
STATUS Output/Power Good Input
Automatic remote sense switching compensates for voltage
Available in 20-Lead Narrow SSOP and 20-Lead QFN
drops across the MOSFETs. The LTC2926 provides two
(4mm 5mm) Packages
integrated switches as well as a signal to control optional
additional external N-channel MOSFET sense switches.
U
APPLICATIO S
The LTC2926 includes I/O signals for communication with
other devices. The status output asserts after tracking and
V and V Supply Tracking
CORE I/O
sequencing have completed. A low voltage on the power
Microprocessor, DSP and FPGA Supplies
good input after an adjustable timeout period causes load
Servers
disconnect. A low voltage on the fault I/O causes immedi-
Communications Systems
ate load disconnect. Until it is reset, a fault latch prevents
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
tracking and keeps the loads disconnected.
*Protected by U.S. Patents including 6897717.
TYPICAL APPLICATIO
1.8V MODULE
3.3V SLAVE2
IRF7413Z
1.8V
OUT
SLAVE1
100
SENSE
10
1.8V SLAVE1
500mV/DIV
3.3V MODULE
IRF7413Z
3.3V
OUT
SLAVE2
0.1F
100
SENSE
10
V SGATE2 SGATE1 2926 TA01b
CC
5ms/DIV
D1 S1
15.0k
D2 FB1
3.3V SLAVE2
9.53k
RAMPBUF
15.0k
S2
15.0k
TRACK1
15.0k
LTC2926 1.8V SLAVE1
9.53k
FB2 500mV/DIV
V
CC
4.02k
TRACK2
V 10k
4.02k CC
STATUS/PGI STATUS
10k
MGATE
FAULT FAULT
0.1F
2926 TA01c
ON/OFF ON
RAMP 5ms/DIV
GND PGTMR
2926 TA01
1F
2926fa
1
U
ULTC2926
ABSOLUTE AXI U RATI GS
(Notes 1, 2)
RMS Currents
Supply Voltage (V ) ................................. 0.3V to 10V
CC
TRACK1, TRACK2 ................................................5mA
Input Voltages
FB1, FB2 ..............................................................5mA
ON ......................................................... 0.3V to 10V
D1, S1, D2, S2 ...................................................30mA
RAMP .............................................0.3V to V + 1V
CC
Operating Temperature
TRACK1, TRACK2 ........................0.3V to V + 0.3V
CC
LTC2926C ................................................ 0C to 70C
PGTMR ........................................0.3V to V + 0.3V
CC
LTC2926I ............................................. 40C to 85C
Input/Output Voltages
Storage Temperature Range
FAULT .................................................... 0.3V to 10V
GN Package ....................................... 65C to 150C
STATUS/PGI (Note 3) .......................... 0.3V to 11.5V
UFD Package ...................................... 65C to 125C
Output Voltages
Lead Temperature (Soldering, 10 sec)
RAMPBUF ....................................0.3V to V + 0.3V
CC
GN Package ...................................................... 300C
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
UUW
PACKAGE/ORDER I FOR ATIO
TOP VIEW
TOP VIEW
V 1 RAMPBUF
20
CC
20 19 18 17
TRACK1 2 TRACK2
19
FB1 1 16 FB2
FB1 3 FB2
18
S1 S2
2 15
S1 4 S2
17
SGATE1 3 14 SGATE2
SGATE1 5 SGATE2
16
21
D1 4 13 D2
D1 6 D2
15
ON 5 12 STATUS/PGI
ON 7 STATUS/PGI
14
PGTMR 6 11 RSGATE
PGTMR 8 RSGATE
13
7 8 9 10
FAULT 9 MGATE
12
GND 10 RAMP
11
GN PACKAGE
UFD PACKAGE
20-LEAD PLASTIC SSOP
20-LEAD (4mm 5mm) PLASTIC QFN
T = 125C, = 85C/W
JMAX JA
EXPOSED PAD (PIN 21) IS GND
PCB CONNECTION OPTIONAL
T = 125C, = 43C/W
JMAX JA
ORDER PART NUMBER ORDER PART NUMBER UFD PART MARKING*
LTC2926CGN LTC2926CUFD 2926
LTC2926IGN LTC2926IUFD 2926
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: