LTC2922.pdf 데이터시트 (총 20 페이지) - 파일 다운로드 LTC2922 데이타시트 다운로드

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LTC2921/LTCw2ww9.D2at2aSheSete4U.rcioem s
Power Supply Tracker
with Input Monitors
FEATURES
DESCRIPTIO
s Tracks Multiple Supplies with MOSFET Switches
s Monitors 5 Input Voltages Including VCC
s Guaranteed Threshold Accuracy: ±1% at 0.5V
s Automatic Remote Sense Switching
s Adjustable Supply Ramp Rate
s Overvoltage Monitor
s Adjustable Electronic Circuit Breaker
s Adjustable Power-Good Delay
s Available for VCC Supply Voltages of 5V, 3.3V and 2.5V
s Available in 16-Pin Narrow SSOP (LTC2921 Series)
and 20-Pin TSSOP (LTC2922 Series)
U
APPLICATIO S
s Desktop Computers
s Plug-In Cards
s Telecom Infrastructure
s Supply Sequencing
s Instruments
The LTC®2921 and LTC2922 monitor up to five supplies
and force them to track on power-up in multiple supply
systems. Using external N-channel pass transistors, the
supplies can be ramped up at an adjustable rate. Auto-
matic remote sense switching allows the DC/DC convert-
ers to compensate for series voltage drops in the wiring.
An incorrect level on one or more of the supplies triggers
disconnect of all supplies. Tight 1% accuracy and glitch
immunity on the low 0.5V monitoring level ensure no false
error disconnects.
The LTC2921 and LTC2922 each feature an adjustable
electronic circuit breaker to protect the VCC supply against
short circuits. Capacitance at the TIMER pin programs the
delays in the monitoring sequence.
The LTC2921 includes three remote sense switches in a
16-pin narrow SSOP package, while the LTC2922 includes
five remote sense switches in a 20-pin TSSOP package.
Both parts are available for VCC supply voltages of 5V,
3.3V, and 2.5V.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Three-Supply Tracker and Monitor (5V, 3.3V, 2.5V)
VOUT 5V SUPPLY
VFB
DC/DC
CONVERTER
100
WSL1206
0.05
Si2316DS
10
5V
LOAD
VOUT 3.3V SUPPLY
VFB
DC/DC
CONVERTER
100
Si2316DS
10
3.3V
LOAD
VOUT 2.5V SUPPLY
VFB 100
DC/DC
CONVERTER
Si1012R
CBRST
100k
CIRCUIT BREAKER
RESET CONTROL
243k 169k
49.9k 49.9k
Si2316DS
10
VCC SENSE
V1 GATE
V2
V3 LTC2921
V4
PG
S1
S2
S3
GND
D1
D2
D3
TIMER
0.47µF
0.22µF
2.5V
LOAD
4.7k
RESET
tGATE ~ 500ms
tTIMER ~ 130ms
2921/22 TA01
Load Voltage Ramp-Up and
Power-Good Activation
2.5V SUPPLY
2V/DIV
OUTPUTS
2V/DIV
5V LOAD
3.3V LOAD
2.5V LOAD
PG
2V/DIV
5V SUPPLY AT 5V 100ms/DIV
3.3V SUPPLY AT 3.3V
2921/22 TA01b
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LTC2921/LTC2922 Series
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ABSOLUTE AXI U RATI GS (Note 1)
VCC Supply Voltage ...................................... –0.3V to 7V
V1, V2, V3, V4 Voltages ............................... –0.3V to 7V
SENSE Voltage ............................................ –0.3V to 7V
TIMER Voltage ............................. –0.3V to (VCC + 0.3V)
Charge Pumped Output Voltages
GATE, PG ............................................ –0.3V to 12.2V
Switch Voltages
S0, D0, S4, D4 (LTC2922 Series) ............ –0.3V to 7V
S1, D1, S2, D2, S3, D3 ............................ –0.3V to 7V
Switch Currents (DC, RMS)
S0, D0, S4, D4 (LTC2922 Series) ..................... 30mA
S1, D1, S2, D2, S3, D3 ..................................... 30mA
Operating Ambient Temperature Range
LTC2921C/LTC2922C .............................. 0°C to 70°C
LTC2921I/LTC2922I ............................–40°C to 85°C
Junction Temperature (Note 2) ............................. 125°C
Storage Temperature Range ..................–65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
UW U
PACKAGE/ORDER I FOR ATIO
TOP VIEW
V1 1
V2 2
V3 3
V4 4
S3 5
D3 6
S2 7
D2 8
16 TIMER
15 VCC
14 SENSE
13 GATE
12 PG
11 GND
10 D1
9 S1
GN PACKAGE
16-LEAD NARROW PLASTIC SSOP
TJMAX = 125°C, θJA = 110°C/W
ORDER PART
NUMBER
LTC2921CGN
LTC2921CGN-3.3
LTC2921CGN-2.5
LTC2921IGN
LTC2921IGN-3.3
LTC2921IGN-2.5
GN PART MARKING
2921
292133
292125
2921I
921I33
921I25
Consult LTC Marketing for parts specified with wider operating temperature ranges.
SO 1
TIMER 2
V1 3
V2 4
V3 5
V4 6
S4 7
D4 8
S3 9
D3 10
TOP VIEW
20 D0
19 VCC
18 SENSE
17 GATE
16 PG
15 GND
14 D1
13 S1
12 D2
11 S2
F PACKAGE
20-LEAD PLASTIC TSSOP
TJMAX = 125°C, θJA = 90°C/W
ORDER PART
NUMBER
LTC2922CF
LTC2922CF-3.3
LTC2922CF-2.5
LTC2922IF
LTC2922IF-3.3
LTC2922IF-2.5
ELECTRICAL CHARACTERISTICS The q denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V for LTC2921/LTC2922, VCC = 3.3V for
LTC2921-3.3/LTC2922-3.3, and VCC = 2.5V for LTC2921-2.5/LTC2922-2.5, unless otherwise noted.
SYMBOL
Supply Pin
VCC
ICC
VCC(MON)
VCC(OV)
PARAMETER
Supply Voltage
Supply Current
Supply Monitor Threshold Voltage
Supply Overvoltage Threshold
CONDITIONS
Typical Operating Range
LTC2921/LTC2922
LTC2921-3.3/LTC2922-3.3
LTC2921-2.5/LTC2922-2.5
LTC2921/LTC2922
LTC2921-3.3/LTC2922-3.3
LTC2921-2.5/LTC2922-2.5
LTC2921/LTC2922
LTC2921-3.3/LTC2922-3.3
LTC2921-2.5/LTC2922-2.5
MIN TYP MAX UNITS
4.50
2.97
2.37
q 4.285
q 2.828
q 2.265
q 5.82
q 3.84
q 3.08
5.00
3.30
2.50
2
4.350
2.871
2.300
6.13
4.04
3.24
5.50
3.63
2.63
4.415
2.914
2.335
6.43
4.24
3.40
V
V
V
mA
V
V
V
V
V
V
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LTC2921/LTCw2ww9.D2at2aSheSete4U.rcioem s
ELECTRICAL CHARACTERISTICS The q denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V for LTC2921/LTC2922, VCC = 3.3V for
LTC2921-3.3/LTC2922-3.3, and VCC = 2.5V for LTC2921-2.5/LTC2922-2.5, unless otherwise noted.
SYMBOL
PARAMETER
VCC(UVLO)
Supply Undervoltage Lockout
VCC(UVH)
Supply Undervoltage Hysteresis
Electronic Circuit Breaker
VSENSE
ISENSE
tV1(DLY)
Circuit Breaker Trip Voltage
SENSE Pin Input Current
Circuit Breaker Trip Delay Time
tV1(RST)
VV1(RST)
Monitor Inputs
VMON
Circuit Breaker Reset Pulse Width
Circuit Breaker Reset Threshold Voltage
V1-V4 Monitor Threshold Voltages
CONDITIONS
VCC Rising
VCC Falling
VSENSE = VCC - VSENSE
VCC - VSENSE = 150mV
LTC2921/LTC2922
LTC2921-3.3/LTC2922-3.3
LTC2921-2.5/LTC2922-2.5
Guaranteed Not to Reset
Guaranteed to Reset
VOV
IMON
TIMER Pin
VTIMER(TH)
ITIMER(PU)
ITIMER(PD)
VTIMER(CLR)
GATE Pin
VGATE
V1-V4 Overvoltage Thresholds
V1-V4 Input Currents
TIMER Ramp Threshold Voltage
TIMER Pull-Up Current
TIMER Pull-Down Current
TIMER Cleared Threshold Voltage
GATE Drive Output Voltage
IGATE(PU)
GATE Pull-Up Current
IGATE(PD)
GATE Pull-Down Current
Remote Sense Switches
RDS(FB)
PG Pin
Feedback Switch Resistances (Note 3)
IPG(PU)
IPG(PD)
VPG(OL)
VPG
PG Pull-Up Current
PG Pull-Down Current
PG Output Low Voltage
PG Output Voltage (Note 4)
VTIMER = 1V
VCC = 2.35V, VTIMER = 0.4V
VTIMER Falling
LTC2921/LTC2922
LTC2921-3.3/LTC2922-3.3
LTC2921-2.5/LTC2922-2.5
VGATE = VCC
VCC = 2.35V, VGATE = 2.35V
VD = VCC
VPG = VCC
VCC = 2.35V, VPG = 2.35V
VCC = 2.35V, IPG = 5mA
LTC2921/LTC2922
LTC2921-3.3/LTC2922-3.3
LTC2921-2.5/LTC2922-2.5
MIN TYP MAX UNITS
q 2.08 2.20 2.30
V
120 mV
q 45
50 55
150 500
0.5
0.5
0.5
q
q 150
q 0.490
1.5
1.5
1.5
0.500
3.0
3.0
6.0
50
0.510
mV
nA
µs
µs
µs
µs
µs
V
0.495
q 0.492
q 0.665
0.500
0.500
0.700
0.505
0.508
0.735
±0.1
V
V
V
µA
q 1.15 1.20 1.25
q –1.3 –2.0 –2.5
100
150 250
V
µA
µA
mV
q 10.0
q 8.4
q 6.1
q –6.5
10
11.1
9.1
6.8
–10.0
12.2
9.8
7.5
–12.5
V
V
V
µA
mA
q
2 10
q –2.6 –4.0 –5.0
10
q 0.4
q 10.0 11.1 12.2
q 8.4 9.1 9.8
q 6.1 6.8 7.5
µA
mA
V
V
V
V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: TJ is calculated from the ambient temperature TA and power
dissipation PD as follows:
LTC2921 Series: TJ = TA + (PD • 110°C/W)
LTC2922 Series: TJ = TA + (PD • 90°C/W)
Note 3: This specification applies to all switches, and is measured with
VS < VD.
Note 4: The PG pin will rise to approximately the same voltage as the
GATE pin when not pulled up or pulled down by external resistance.
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LTC2921/LTC2922 Series
TYPICAL PERFOR A CE CHARACTERISTICS
Specifications are at TA = 25°C unless otherwise noted.
Supply Current vs Supply Voltage
3.00
PG SIGNAL ASSERTED
2.75
2.50
2.25
LTC2921-3.3
LTC2922-3.3
2.00 LTC2921-2.5
LTC2922-2.5
1.75
LTC2921
LTC2922
1.50
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
VCC (V)
2921/2 G01
Monitor Input Threshold vs
Temperature
0.505
Supply Current vs Temperature
2.6
PG SIGNAL ASSERTED
2.4
LTC2921-3.3
2.2 LTC2922-3.3
LTC2921
LTC2922
LTC2921-2.5
2.0 LTC2922-2.5
1.8
–50 –30
–10 10 30 50
TEMPERATURE (°C)
70 90
2921/2 G02
Circuit Breaker Trip Voltage vs
Temperature
55
0.500
50
0.495
–50 –30 –10 10 30 50
TEMPERATURE (°C)
70 90
2921/2 G04
TIMER Trip Voltage
vs Temperature
1.21
1.20
1.19
–50 –30 –10 10 30 50
TEMPERATURE (°C)
70 90
2921/2 G07
4
45
–50 –30 –10 10 30 50
TEMPERATURE (°C)
70 90
2921/2 G05
TIMER Pull-Up Current
vs Temperature
2.5
VTIMER = 1V
2.4
2.3
2.2
2.1
2.0
1.9
1.8
1.7
1.6
1.5
–50 –30
–10 10 30 50
TEMPERATURE (°C)
70 90
2921/2 G08
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Monitor Trip Delay vs
Monitor Input Overdrive
100
80
60
LTC2921-2.5
LTC2922-2.5
40
LTC2921/LTC2922
LTC2921-3.3/LTC2922-3.3
20
0
0 20 40 60 80 100 120 140
MONITOR INPUT OVERDRIVE (mV)
2921/2 G03
SENSE Input Current
vs Temperature
250
VSENSE = VCC
200
150
100
50
0
–50 –30 –10 10 30 50
TEMPERATURE (°C)
70 90
2921/2 G06
TIMER Pull-Down Current
vs Supply Voltage
170
VTIMER = 0.4V
165
160
155
150
145
140
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
VCC (V)
2921/2 G09
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LTC2921/LTCw2ww9.D2at2aSheSete4U.rcioem s
TYPICAL PERFOR A CE CHARACTERISTICS
Specifications are at TA = 25°C unless otherwise noted.
Gate Voltage vs Supply Voltage
12 GATE LOAD = 1000pF || 10M
PG LOAD = 2kTO VCC
11 VCC BYPASS CAP = 1µF
LTC2921
LTC2922
10
9
LTC2921-3.3
8 LTC2922-3.3
7 LTC2921-2.5
LTC2922-2.5
6
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
VCC (V)
2921/2 G10
GATE Pull-Up Current
vs Temperature
11.5
VGATE = VCC
11.0
10.5
10.0
9.5
9.0
8.5
–50 –30
–10 10
30
50
TEMPERATURE (°C)
70 90
2921/2 G13
Gate Voltage vs Temperature
12
11 LTC2921
LTC2922
10
LTC2921-3.3
LTC2922-3.3
9
GATE LOAD = 1000pF || 10M
PG LOAD = 2kTO VCC
8 VCC BYPASS CAP = 1µF
LTC2921-2.5
7 LTC2922-2.5
6
–50 –30
–10 10 30 50
TEMPERATURE (°C)
70 90
2921/2 G11
PG Voltage vs Supply Voltage
12 GATE LOAD = 1000pF || 10M
PG LOAD = 1000pF || 10M
11 VCC BYPASS CAP = 1µF
LTC2921
LTC2922
10
LTC2921-3.3
9 LTC2922-3.3
8
LTC2921-2.5
7 LTC2922-2.5
6
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
VCC (V)
2921/2 G14
Gate Voltage vs Load Current
12
LTC2921
LTC2922
10
8
LTC2921-3.3
LTC2922-3.3
6
LTC2921-2.5
LTC2922-2.5
4
GATE LOAD = 1000pF || 10M
2 PG LOAD = 2kTO VCC
VCC BYPASS CAP = 1µF
0
0 1 2 3 4 5 6 7 8 9 10
LOAD CURRENT (µA)
2921/2 G12
PG Pull-Up Current vs
Temperature
5.5
VPG = VCC
5.0
4.5
4.0
3.5
3.0
2.5
–50 –30
–10 10 30 50
TEMPERATURE (°C)
70 90
2921/2 G15
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