POWER MANAGEMENT
1www.semtech.com
SC1112
Triple Low Dropout
Regulator Controllers
Features
Applications
Revision: August 30, 2006
Typical Application Circuit
Description
The SC1112 was designed for the latest high speed
motherboards. It includes three low dropout regulator con-
trollers. The controllers provide the power for the system
AGTL bus Termination Voltage, Chipset, and clock circuitry.
An adjustable controller with a 1.2V reference is available,
while two selectable outputs are provided for the VTT
(1.25 V or 1.5V, SC1112) or (1.2V or 1.5V, SC1112A)
and the AGP (1.5V or 3.3V). The SC1112 low dropout
regulators are designed to track the 3.3V power supply
as the VTTIN supply is cycled On and Off. A latched short
circuit protection is also available for the VTT output.
Other features include an integrated charge pump that
provides adequate gate drives for the external MOSFETs,
and a capacitive programable delay for the power good
signal.
Triple linear controllers
Selectable and adjustable output voltages
LDOs track input voltage within 200mV (Function of
the MOSFETs used) until regulation
Integrated charge pump
Programmable power good delay signal
Latched over current protection (VTT)
Pb-free package available, fully WEEE and RoHS
compliant
Pentium® III Motherboards
Triple power supplies
Q1
RA
SC1112/A
PWRGD
DELAY
5VSTBY
VTTSEL
AGPSEL
GND
FC
CAP+
CAP- VTTGATE
VTTSEN
AGPGATE
AGPSEN
ADJGATE
ADJSEN
VTTIN
A
DJ
Q2 C14
330u
C12
330u
AGP SELECT Signal
C8
330u
AGP
C17
0.1u
RB
C16
330u
C3
0.1u
C1
10u
C18
330u
VTT SELECT Signal
POWER GOOD
C5
22n
C10
1u
C13
0.1u
+3.3V
R1
1K
+5V STBY
Q3
C11
0.1u
C9
0.1u
VTT
C6
330u
VTT
C19
330u
C2
22006 Semtech Corp. www.semtech.com
POWER MANAGEMENT
SC1112
Electrical Characteristics
Absolute Maximum Ratings
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DNGotNESPGA 5ot3.0-V
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CIOS
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CIOS
POSST θ
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Unless specified: 5VSTBY=4.75V to 5.25V; VTTIN=3.3V; TA = 25°C
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Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified
in the Electrical Characteristics section is not implied.
3
2006 Semtech Corp. www.semtech.com
POWER MANAGEMENT
SC1112
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WOL=LESTTV,A2ot0=671.1002.1422.1V
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TTV
52.1
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WOL=LESTTV,A2ot0=522.1052.1572.1
TTV
5.1
I
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HGIH=LESTTV,A2ot0=074.1005.1035.1V
PGAegatloVtuptuOPGA
5.1
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WOL=LESPGA,A2ot0=074.1005.1035.1V
PGA
3.3
I
O
HGIH=LESPGA,A2ot0=432.3003.3V
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A2ot0=%2-)BR/AR+1(*2.1%2+V
tnerruCsaiBNESTTV
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saibI
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saibI
NESTTV
15Aµ
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NESPGA
011051071Aµ
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15Aµ
tnerruCetaGTTVecruosI
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V0.3=etagV,V57.4=YBTSV5005Aµ
knisI
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005Aµ
tnerruCetaGPGAecruosI
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knisI
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Electrical Characteristics (Cont.)
Unless specified: 5VSTBY=4.75V to 5.25V; VTTIN=3.3V; TA = 25°C
Notes:
(1) All electrical characteristics are for the application circuit on page 19.
(2) Guaranteed by design
(3) Tracking Difference is defined as the delta between 3.3V Vin and the VTT, AGP, ADJ output voltages during the linear ramp up until
regulation is achieved. The Tracking Voltage difference might vary depending on MOSFETs Rdson, and Load Conditions.
(4) During power up, an internal short circuit glitch timer will start once the VTT Input Voltage exceeds the VTTINTH (1.5V). During the glitch
timer immunity time, determined by the Delay capacitor (Delay time is approximately equal to (Cdelay*SCTH)/ISC), the short circuit
protection is disabled to allow VTT output to rise above the trip threshold (0.7V). If the VTT output has not risen above the trip
threshold after the immunity time has elapsed, the VTT output is latched off and will only be enabled again if either the VTT input
voltage or the 5VSTBY is cycled.
(5) PWRGD pin is kept low during the power up, until the VTT output has reached its PGtd1.2 or PGtd1.5 level. At that time the PWRGD
source current IPG (20uA) is enabled and will start charging the external PWRGD delay capacitor connected to the DELAY pin. Once the
capacitor is charged above the PGDelay_TH (1.5V), the PWRGD pin is released from ground.
42006 Semtech Corp. www.semtech.com
POWER MANAGEMENT
SC1112
VTTGATE
VTTIN=1.5V
The delay capacitor does not
begin charging until VTTIN has
reached 1.5V and VTT is above
the powergood threshold of
1.08V.
Once DELAY reaches 1.5V,
the PWRGD signal goes high.
VTTGATE initially turns on
hard, until VTT reaches
regulation. Then VTTGATE
drops to its normal regulating
level.
PWRGD
DELAY
VTT
VTTIN
DELAY=1.5V
NORMAL STARTUP CONDITION
The delay capacitor does not
begin charging until VTTIN has
reached 1.5V and VTT is below
the short circuit threshold of
0.7V.
VTTGATE initially turns on hard
and is latched off when DELAY
reaches 1.5V and VTT is below
0.7V
DELAY
VTT
PWRGD
VTTIN
VTTGATE
VTTIN=1.5V
SHORT-CIRCUIT STARTUP
DELAY=1.5V
Timing Diagrams
5
2006 Semtech Corp. www.semtech.com
POWER MANAGEMENT
SC1112
PWRGD
DELAY=1.5V
DELAY
VTT
SHORT-CIRCUIT DURING NORMAL
OPERATION
Once VTT drops out of
regulation, VTTGATE turns on
harder to try and raise VTT.
When VTT drops below 1.08V,
the delay capacitor is
discharged and PWRGD goes
low. When VTT drops below
0.7V, the delay capacitor
begins charging.
If VTT is still below 0.7V when
DELAY reaches 1.5V,
VTTGATE is latched off.
VTTIN
VTT=0.7V
VTT=1.08V
VTTGATE
VTT=0.7V
PWRGD
VTT=1.08V
DELAY
SHORT-CIRCUIT AND RECOVERY
DURING NORMAL OPERATION
VTT
Once VTT drops out of
regulation, VTTGATE turns on
harder to try and raise VTT.
When VTT drops below 1.08V,
the delay capacitor is discharged
and PWRGD goes low. When
VTT drops below 0.7V, the delay
capacitor begins charging.
If VTT recovers above 0.7V
before DELAY reaches 1.5V,
DELAY is again discharged.
If VTT reaches 1.08V the delay
capacitor begins charging and
normal operation continues.
VTTIN
VTT=1.08V
VTTGATE
DELAY=1.5V
Timing Diagrams (Cont.)
62006 Semtech Corp. www.semtech.com
POWER MANAGEMENT
SC1112
Pin Configuration Ordering Information
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RTS2111CS
61-OSC°521ot°0TRTS2111CS
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RTSA2111CS
RTST2111CS
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RTSTA2111CS
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Notes:
(1) Only available in tape and reel packaging. A reel contains
2500 devices.
(2) Part Number (SO-16): SC1112STR and SC1112STRT =
1.25V and SC1112ASTR = 1.2V.
Part Number (TSSOP-16): SC1112TSTR = 1.25V and
SC1112ATSTR = 1.2V.
(3) Pb-free product. This product is fully WEEE and RoHS
compliant.
Top View
(16-Pin SOIC or TSSOP)
PWRGD
5VSTBY
DELAY
VTTSEL
AGPSEL
ADJGATE
ADJSEN
CAP+
GND
VTTIN
VTTGATE
AGPGATE
VTTSEN
AGPSEN
FC
CAP-
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
7
2006 Semtech Corp. www.semtech.com
POWER MANAGEMENT
SC1112
Pin Descriptions
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3YALED TTVfogalFdooGrewoPehtrofyaledehtmargorplliwDNGotnipsihtmorfroticapacA
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4LESTTV VX2.1=TTV,WOL=LESTTV:egatlovtuptuoTTVehtsmargorptahtlangisLTT
V5.1=TTV,HGIH=LESTTV
5LESPGA V5.1=PGA,WOL=LESPGA:egatlovtuptuoPGAehtsmargorptahtlangisLTT
V3.3=PGA,HGIH=LESPGA
6ETAGJDA.PGAroftuptuoevirdetaG
7NESJDA.JDAroftupniesneS
8-PAC.roticapactsoobotnoitcennocevitageN
9+PAC.roticapactsoobotnoitcennocevitisoP
01CF .DNGotnipsihtmorfdetcennocebdluohspmupegrahclanretniehtrofroticapacretliF
11NESPGA.PGAroftupniesneS
21ETAGPGA.PGAroftuptuoevirdetaG
31NESTTV.TTVroftupniesneS
41ETAGTTV.TTVroftuptuoevirdetaG
51NITTV.niV3.3ehtotdetcennocenilesnestiucrictrohS
61DNG.dnuorG
NOTE: (1) All logic level inputs and outputs are open collector TTL compatible.
82006 Semtech Corp. www.semtech.com
POWER MANAGEMENT
SC1112
Block Diagram
Vref
1.5V
1.08V
+
DELAY
ADJGATE
VTTSEN
1.5V
Bandgap
_
_
Vref
ChargePump
1.2V
Disable3.3
+ _
AGPSEN
0.7V
Disable1.5
5VSTBY
VTTSEN
+
S
_
VTTGATE
GND
1.5V
_
+
AGPGATE
0.7V
_
+
VTTSEL
_
1.5V
+
+
_
R
Pwrgd
Threshold
AGPSEL
+
-
VTTIN
+
1.2V
FC
_
Q
CAP-
1.35V
CAP+
FC
PWRGD
+
+
Disable1.2
Oscillator
1.2V
Disable1.5
ADJSEN
Reference
FC
_
+
_
9
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POWER MANAGEMENT
SC1112
Typical Characteristics
1.4995
1.5000
1.5005
1.5010
1.5015
1.5020
1.5025
1.5030
1.5035
0 10203040506070
Ta (°C.)
VTT1.5 (V)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
1.2445
1.2450
1.2455
1.2460
1.2465
1.2470
1.2475
1.2480
1.2485
0 10203040506070
Ta (°C.)
VTT1.2(V)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
1.5015
1.5020
1.5025
1.5030
1.5035
1.5040
1.5045
1.5050
1.5055
0 10203040506070
Ta (°C.)
VTT1.5(V)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
VTT(1.5V) Output Voltage @ Io = 0A vs Ta
VTT(1.25V) Output Voltage @ Io = 0A vs Ta
VTT Input Supply Threshold vs Ta
VTT(1.5V) Output Voltage @ Io = 2A vs Ta
1.2425
1.2430
1.2435
1.2440
1.2445
1.2450
1.2455
1.2460
1.2465
0 10203040506070
Ta (°C.)
VTT1.2(V)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
VTT(1.5V) Output Voltage @ Io = 2A vs Ta
104
106
108
110
112
114
116
0 10203040506070
Ta (°C.)
IbiasVTTSEN (uA)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
VTT Sense Bias current vs Ta
1.491
1.492
1.493
1.494
1.495
1.496
1.497
1.498
0 10203040506070
Ta (°C.)
VTTINTH(V)
5V Stby = 4.75V
5V Stby = 5.00V
5V Stby = 5.25V
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SC1112
Typical Characteristics (Cont.)
400
450
500
550
600
650
700
750
800
0 10203040506070
Ta (°C.)
IVTT_Gate(uA)
Source current
Sink current
VTT Gate Current @ Vgate = 3V, 5V Stby = 4.75V vs Ta
21.60
21.80
22.00
22.20
22.40
22.60
22.80
23.00
23.20
23.40
23.60
0 10203040506070
Ta (°C.)
ISC(uA)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
VTT Short circuit Delay source current vs Ta
7.70
7.80
7.90
8.00
8.10
8.20
8.30
8.40
0 10203040506070
Ta (°C.)
SCtd(mS)
5V Stby = 4.75V
5V Stby = 5.00V
5V Stby = 5.25V
VTT Short circuit Delay Time (Cdelay = 0.1uF) vs Ta
1.465
1.470
1.475
1.480
1.485
1.490
1.495
1.500
1.505
1.510
1.515
0 10203040506070
Ta (°C.)
SCth(V)
5V Stby = 4.75V
5V Stby = 5.00V
5V Stby = 5.25V
VTT Short circuit Delay Timer Threshold vs Ta
11
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POWER MANAGEMENT
SC1112
7.70
7.80
7.90
8.00
8.10
8.20
8.30
8.40
0 10203040506070
Ta (°C.)
PGtd_1.25(mS)
5V Stby = 4.75V
5V Stby = 5.00V
5V Stby = 5.25V
7.70
7.80
7.90
8.00
8.10
8.20
8.30
8.40
0 10203040506070
Ta (°C.)
PGtd_1.5(mS)
5V Stby = 4.75V
5V Stby = 5.00V
5V Stby = 5.25V
21.40
21.60
21.80
22.00
22.20
22.40
22.60
22.80
23.00
23.20
23.40
23.60
0 10203040506070
Ta (°C.)
IPG(uA)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
Typical Characteristics (Cont.)
1.080
1.082
1.084
1.086
1.088
1.090
1.092
1.094
1.096
1.098
0 10203040506070
Ta (°C.)
PGTH_1.25(V)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
1.350
1.351
1.352
1.353
1.354
1.355
1.356
1.357
1.358
1.359
1.360
1.361
0 10203040506070
Ta (°C.)
PGTH_1.5 (V)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
VTT (1.25V) Power Good Threshold vs Ta VTT (1.25V) Power Good Delay Time vs Ta
VTT (1.5V) Power Good Delay Time vs Ta
VTT Power Good Source current vs Ta
VTT (1.5V) Power Good Threshold vs Ta
122006 Semtech Corp. www.semtech.com
POWER MANAGEMENT
SC1112
128
130
132
134
136
138
140
142
0 10203040506070
Ta (°C.)
IbiasAGPSEN (uA)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
3.2820
3.2830
3.2840
3.2850
3.2860
3.2870
3.2880
3.2890
3.2900
0 10203040506070
Ta (°C.)
AGP3.3(V)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
3.2820
3.2830
3.2840
3.2850
3.2860
3.2870
3.2880
3.2890
3.2900
0 10203040506070
Ta (°C.)
AGP3.3(V)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
Typical Characteristics (Cont.)
1.5005
1.5010
1.5015
1.5020
1.5025
1.5030
1.5035
1.5040
1.5045
1.5050
1.5055
0 10203040506070
Ta (°C.)
AGP1.5(V)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
AGP (1.5V) Output Voltage @ Io = 0A vs Ta
AGP (3.3V) Output Voltage @ Io = 0A vs Ta
AGP Sense Bias current vs Ta
1.4985
1.4990
1.4995
1.5000
1.5005
1.5010
1.5015
1.5020
1.5025
1.5030
1.5035
0 10203040506070
Ta (°C.)
AGP1.5(V)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
AGP (1.5V) Output Voltage @ Io = 2A vs Ta
AGP (3.3V) Output Voltage @ Io = 2A vs Ta
600
650
700
750
800
850
900
0 10203040506070
Ta (°C.)
IAGP_Gate(uA)
Sink current
Source current
AGP Gate Current @ Vgate = 3V, 5V Stby = 4.75 vs Ta
13
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SC1112
1.1915
1.1920
1.1925
1.1930
1.1935
1.1940
1.1945
1.1950
1.1955
0 10203040506070
Ta (°C.)
ADJ1.2(V)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
600
650
700
750
800
850
900
0 1020304050607
0
Ta (°C.)
IADJ_Gate(uA)
Sink current
Source current
Typical Characteristics (Cont.)
ADJ (1.2V) Output Voltage @ Io = 0A vs Ta
1.1950
1.1960
1.1970
1.1980
1.1990
1.2000
1.2010
1.2020
0 10203040506070
Ta (°C.)
ADJ1.2(V)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
ADJ (1.2V) Output Voltage @ Io = 2A vs Ta
ADJ Sense Bias current vs Ta
150
170
190
210
230
250
270
290
310
330
350
0 10203040506070
Ta (°C.)
IbiasADJSEN (uA)
5V Stby = 4.75V
5V Stby = 5.00V
5V Stby = 5.25V
ADJ Gate Current @ Vgate = 3V, 5V Stby = 4.75V vs Ta
142006 Semtech Corp. www.semtech.com
POWER MANAGEMENT
SC1112
100.0E-3
110.0E-3
120.0E-3
130.0E-3
140.0E-3
150.0E-3
160.0E-3
170.0E-3
180.0E-3
0 10203040506070
Ta (°C.)
Load Regulation(%)
VTT 1.25V
AGP 1.25V
000.0E+0
20.0E-3
40.0E-3
60.0E-3
80.0E-3
100.0E-3
120.0E-3
140.0E-3
160.0E-3
0 10203040506070
Ta (°C.)
Line Regulation(%)
VTT 1.25V
AGP 1.25V
1.20
1.25
1.30
1.35
1.40
1.45
1.50
1.55
1.60
0 10203040506070
Ta (°C.)
Output Select Threshold (V)
VTTSEL
AGPSEL
5.50
5.70
5.90
6.10
6.30
6.50
6.70
6.90
7.10
7.30
7.50
0 10203040506070
Ta (°C.)
I5vstby (mA)
5V Stby = 5.25V
5V Stby = 5.00V
5V Stby = 4.75V
9.21
9.22
9.23
9.24
9.25
9.26
9.27
9.28
9.29
9.30
9.31
9.32
0 10203040506070
Ta (°C.)
V Charge Pump(V)
V Charge Pump
345
350
355
360
365
370
375
0 10203040506070
Ta (°C.)
Charge Pump Frequency (kHz)
Charge Pump Frequency
Typical Characteristics (Cont.)
I 5V Stby vs Ta
Line Regulation VTTIN = 3.13V to 3.47V Io = 2A vs Ta
Charge Pump Output Voltage vs Ta Charge Pump Frequency vs Ta
Load Regulation VTTIN = 3.3V Io = 0 to 2A vs Ta
Output Select Threshold vs Ta