VRM9.0 PROGRAMMABLE, MULTI-PHASE,
HIGH PERFORMANCE PWM CONTROLLER
SC1146
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
July 25, 2000
1
The SC1146 is patent pending
Pentium is a registered trademark of Intel Corporation
BLOCK DIAGRAM
FEATURES
•
=
Allows use of small surface mount components
•
=
Ultra fast transient recovery time
•
=
Dramatic reduction of input ripple current and out-
put ripple voltage
•
=
5-bit programmable DAC for the latest, lower
output voltage Microprocessors
•
=
Wide, High frequency operating range
•
=
Selectable 2, 3, 4 phase operation
•
=
+5 Volt only operation eliminates the need for
+12V supply
•
=
Precision load current sharing,1%PWM match
•
=
Selectable internal or external clock
•
=
Soft start/UVLO/Over current protection
APPLICATIONS
•
=
High end servers and workstations
•
=
High current/Ultra-fast transient microprocessors
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DEVICE
(1)
PACKAGE
TEMP. (T
J
)
SC1146CSW.TR
SO-24
0 - 85°C
ORDERING INFORMATION
Note:
(1) Only available in tape and reel packaging. A reel
contains 1000 devices.
DESCRIPTION
The SC1146 is the latest, high performance, multi-
phase (PWM) controller designed for high power mi-
croprocessors requiring ultra fast transient response.
The SC1146 is programmable for the voltage range
required by the latest Microprocessors . Utilizing a
novel and unique design, the controller distributes the
output load across (up to) four converter channels by
digitally phase shifting the PWM outputs. This ap-
proach greatly reduces the stress and heat on the out-
put stage components while lowering input ripple cur-
rent by as much as 80%. Accurate current sharing
among the four phases is achieved by precision design
techniques and trimming of critical elements.
The high speed transconductance error amplifier is ex-
ternally initialized using a soft-start capacitor allowing
the controller to “wake-up” without overshoot, thus pro-
tecting the low voltage microprocessor loads. The out-
put drive voltage to the power MOSFETs is pro-
grammable to minimize switching losses in the drive
circuitry.
The output voltage is digitally programmable by means
of a 5 bit DAC (new codes). A single resistor programs
the master clock frequency (8MHz max) or the clock
can be supplied by an external source where exact fre-
quency control is desired. The number of operating
phases is programmed independently of the external
clock. The parts features under-voltage lock-out with
hysteresis and over-current protection.
PIN CONFIGURATION
Top View
(24-Pin SOIC)
VRM9.0 PROGRAMMABLE, MULTI-PHASE,
HIGH PERFORMANCE PWM CONTROLLER
SC1146
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
July 25, 2000
2
The SC1146 is patent pending
ELECTRICAL CHARACTERISTICS
Unless otherwise noted: T
A
= 25
°
C, V
CC 5V
= 5V, V
CC2
= 5V, 4-Phase operation.
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage Range
V
CC2
3.9
5.0
15.0
V
UVLO Range
V
CC5V
3.9
5.0
6.0
V
UVLO Hystersis
V
CC5V
TBD
mV
Supply Voltage Range
V
CC5V
4.5
5.0
5.5
V
Supply Current
V
CC2
DRV Outputs open
10
mA
Supply Current
V
CC5V
V
OUT
= 2.00V, I
O
= 0
40
mA
Reference Current Pin Voltage
V
REF
Iref = 250µA
2.05
V
VID0-4 Clock Select & Divide
V
INL
Logic Low
0.8
V
Select Logic Threshold
V
INH
Logic High
2
V
VID0-4 Clock Select & Divide
I
INL
Vid0-4 = 0V
-20
µA
Select Input Bias Current
I
INH
Vid0-4 = 4.5V
+50
µA
Enable Pin
V
INL
.8
V
V
INH
2
V
Maximum Duty Cycle
D
MAX
FB = 0V
75
%
DRV0-3 Output Voltage
V
OL
I
sink
= 1mA
.3
V
V
OH
I
source
= 1mA, PWRGOOD = V
cc5v
V
CC2
-1
V
DRV0-3 Source Current
I
SRC
V
OUT
= 2.00V
40
mA
DRV0-3 Sink Current
I
SNK
V
OUT
= 2.00V
20
mA
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Limits
Units
V
CC5V
to GND
V
cc5v
-0.3 to + 12
V
FBG to GND
FBG
± 1
V
V
CC2
to GND
V
cc2
-0.3 to +20
V
Operating Temperature Range
T
A
0 to +70
°C
Junction Temperature Range
T
J
0 to +125
°C
Storage Temperature Range
T
STG
-55 to +150
°C
Thermal Resistance Junction to Case
θ
JC
25
°C/W
Thermal Resistance Junction to Ambient
θ
JA
80
°C/W
Lead Temperature (Soldering) 10 sec
T
LEAD
300
°C
VRM9.0 PROGRAMMABLE, MULTI-PHASE,
HIGH PERFORMANCE PWM CONTROLLER
SC1146
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
July 25, 2000
3
The SC1146 is patent pending
O
OUT
I
V
∆
∆
IN
OUT
V
V
∆
∆
ELECTRICAL CHARACTERISTICS (Cont.)
Unless otherwise noted: T
A
= 25
°
C, V
CC5V
= 5V, V
CC2
= 5V, 4-Phase operation.
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX UNITS
Bgout Voltage
V
Bgout
Vid = 00000
TBD
1.30
TBD
V
Bgout Impedance
R
O_Bg
3
K
Ω
External Clock Freq. Range
F
ext_CK
.80
8.0
8.5
MHz
Oscillator Frequency
F
OSC
Iref = 250µA
7.6
8.0
8.4
MHz
Internal Clock Freq. Range
F
int_CK
.80
8.0
8.5
MHz
Match DRV0-3
∆
=
D
Duty cycle (Avg) = 50%
-1
+1
%
PWM Off Time
Toff
25
%
Overcurrent Comparator,
Comparator, Common Mode
Range
OCC_CMR
3
15
V
OC+I/P bias Current
IB_OC+
Vin = 5V
+75
+250
µ
Α
OC-I/P bias Current
IB_OC-
Vin = 5V
+75
+250
µ
Α
Input Offset Voltage
VOS_OCC
Vin = 5V
10
mV
Feedback Input Impedance
Ri_FB
V
O
= 2.00V
12
ΚΩ
Duty Cycle Range
D
0
75
%
CONVERTER SPECIFICATIONS, Reference Application Circuit
Output Accuracy Over Set
Range
V
OUT
VID 0-4 = 0000-1111
V
CC5V
= 5.0V
-1
+1
%
Load Regulation
V
O
= 2.000V
I
O
= 3A - 20A
.025
.05
%/A
Line Regulation
V
CC5V
= 5V,
V
O
= 2.000V
V
IN
= 4-6V, (V
IN
separated from
Vcc5v) I
O
= 5A , Clk = external
.15
%/V
POWER GOOD SIGNAL
Off Leakage Current
I
leakage_Off
PWRGOOD = Logic High
2
µA
Power Good Max Sink Current
I
Sink_Max
PWRGOOD< = .8V
2
mA
Power Good Threshold
P
wrgood_T_lo
Vout = 1.300V - 1.950V
+
100
mV
Voltage Tolerance
P
wrgood_T_Hi
Vout = 2.000V - 3.500V
+
150
mV
Note:
(1) This device is ESD sensitive. Use of standard ESD handling precautions is required.
VRM9.0 PROGRAMMABLE, MULTI-PHASE,
HIGH PERFORMANCE PWM CONTROLLER
SC1146
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
July 25, 2000
4
The SC1146 is patent pending
NOTE: (1) All logic inputs and outputs are open collector TTL compatible.
PIN DESCRIPTION
Pin #
Pin Name
Pin Function
1
V
CC 5V
Supply voltage input (5V nominal)
2
Divsel
Connect to Gnd for four phase operation and to logic High for three Phase
operation.
3
Clksel
Clock Select: Logic High selects internal clock. Logic Low selects external
clock.
4
Extclk
External Clock Input. The output frequency is determined by (Clock Input
Freq.)/4. Output freq.= (Clock Input)/4. Pull up to Vcc5v to select internal
clock.
5
R
REF
Connects to external reference resistor. Sets the operating frequency of
the internal clock and the ramp time for the PWM. Reference voltage at
this pin is 2.05V. Trimmed to set 250µA at 8MHz.
6
VID0
(1)
Programming Input (LSB)
7
VID1
(1)
Programming Input
8
VID2
(1)
Programming Input
9
VID3
(1)
Programming Input
10
VID4
(1)
Programming Input (MSB)
11
OC+
Over current comparator. Non-Inverting input.
12
OC-
Over current comparator. Inverting input.
13
COMP
Compensation Pin. Compensation is acheived by connecting a capacitor in
series with a resistor between this pin and FBG. A 300K ohm resistor
must also be directly connected between this pin and FBG.
14
FB
Feedback input connected to supply output.
15
BG
OUT
Bandgap Reference Output. Output resistance = 3Kohm. Must be
bypassed with 4.7nF-100nF capacitor to FBG. This capacitor programs the
soft start time.
16
FBG
Feedback Ground. This pin must be connected to return side of output
caps. This pin is not internally connected to GND.
17
ENABLE
Connects to 5V to ENABLE. Connect to GND to disable entire device.
18
GND
Ground Pin
19
DRV2
Phase 2 output, output voltage range ~.3V - V
CC2
- 1V.
20
DRV0
Phase 0 output, output voltage range ~.3V - V
CC2
- 1V.
21
VCC2
Supply voltage for the DRV0-3, may be connected to +5V or +12V supply.
There is no Undervoltage Lockout on this pin.
22
DRV1
Phase 1 output, output voltage range ~.3V - V
CC2
- 1V.
23
DRV3
Phase 3 output, output voltage range ~.3V - V
CC2
- 1V.
24
PWRGOOD
Power good should be pulled-up to 5V supply via a 3K - 10K resistor.
VRM9.0 PROGRAMMABLE, MULTI-PHASE,
HIGH PERFORMANCE PWM CONTROLLER
SC1146
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
July 25, 2000
5
The SC1146 is patent pending
OUTPUT VOLTAGE
Unless specified: 0 = GND; 1 = High (or Floating).
T
A
= 25
°
C, V
CC5V
= 5V, V
CC2
= 5V, 4-Phase operation.
V
CCCORE
VID4
VID3
VID2
VID1
VID0
(VDC)
1
1
1
1
1
Output Off
1
1
1
1
0
1.1
1
1
1
0
1
1.125
1
1
1
0
0
1.15
1
1
0
1
1
1.175
1
1
0
1
0
1.2
1
1
0
0
1
1.225
1
1
0
0
0
1.250
1
0
1
1
1
1.275
1
0
1
1
0
1.3
1
0
1
0
1
1.325
1
0
1
0
0
1.35
1
0
0
1
1
1.375
1
0
0
1
0
1.4
1
0
0
0
1
1.425
1
0
0
0
0
1.45
0
1
1
1
1
1.475
0
1
1
1
0
1.5
0
1
1
0
1
1.525
0
1
1
0
0
1.55
0
1
0
1
1
1.575
0
1
0
1
0
1.6
0
1
0
0
1
1.625
0
1
0
0
0
1.65
0
0
1
1
1
1.675
0
0
1
1
0
1.7
0
0
1
0
1
1.725
0
0
1
0
0
1.75
0
0
0
1
1
1.775
0
0
0
1
0
1.8
0
0
0
0
1
1.825
0
0
0
0
0
1.85
V
R
M9
.0
P
R
O
G
R
A
MMA
BLE
, MULTI
-P
HA
S
E
,
HIGH P
E
R
FORMA
NCE
P
W
M CONTROLLE
R
SC1146
© 2000 SEMT
E
CH CO
RP.
652 MIT
CHELL RO
AD NEW
B
URY
PARK CA 91320
Ju
ly
25, 2000
6
T
he S
C
1146 i
s patent pendi
ng
E
V
A
LUA
T
ION BOA
RD S
CHE
MA
TIC
EN
EN
VOUT
EN
SMOD
+12V
VO
U
T
ENSYN
Power Good
sel
R22
10K
R20
R6
10K
10
R1
open
R24
R5
10K
TBD
R18
100
R19
0
R17
0
R2
0
R23
0
R3
0
R12
0
R14
0
R16
TBD
R27
0
R26
0
R10
22
R9
22
R11
22
R13
R7
10K
22u,10V
C20
22u,10V
C21
1
R21
22u,10V
C24
2.2
R25
J1
INPUT
1
2
3
4
5
6
S1
Vout/Clk switch
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
22u,10V
C17
22u,10V
C15
1u,
16V
C12
22u,10V
C10
U5
SC1405B
13
4
3
2
1
14
6
5
10
7
9
11
12
8
TG
CO
GND
EN
OVP_S
BST
DELAY_C
S_MOD PGND
PRDY
BG
DSPS_DR
DRN
Vcc
10u,16V
C19
10u,16V
C36
U3
SC1405B
13
4
3
2
1
14
6
5
10
7
9
11
12
8
TG
CO
GND
EN
OVP_S
BST
DELAY_C
S_MOD PGND
PRDY
BG
DSPS_DR
DRN
Vcc
1u,
16V
C11
D6
30BQ015
D7
30BQ015
D1
SS12
D3
SS12
D4
SS12
22u,10V
C25
22u,10V
C30
22u,10V
C29
FDB7030
Q4
FDB7030
Q6
FDB7030
Q8
D2
SS12
U1
SC1405B
13
4
3
2
1
14
6
5
10
7
9
11
12
8
TG
CO
GND
EN
OVP_S
BST
DELAY_C
S_MOD PGND
PRDY
BG
DSPS_DR
DRN
Vcc
U4
SC1405B
13
4
3
2
1
14
6
5
10
7
9
11
12
8
TG
CO
GND
EN
OVP_S
BST
DELAY_C
S_MOD PGND
PRDY
BG
DSPS_DR
DRN
Vcc
22u,10V
C33
22u,10V
C34
22u,10V
C6
22u,10V
C1
22u,10V
C38
R4
10K
D5
30BQ015
FDB7030
Q2
FDP6035
Q1
10u,16V
C28
FDP6035
Q3
FDP6035
Q5
FDP6035
Q7
PID1103-1u
L1
PID1103-1u
L3
PID1103-1u
L5
C43
.001
.1u
C42
.1u C40
.1u
C22
10
uf,6
.3
v
C8
.01
C45
47pf
C44
47pf
C16
47pf
C37
.1
C46
47pf
C26
330U
F,
16V
C13
.1
u
C7
.1
u
C1
4
.1
u
C2
3
.1
u
C3
2
.1
u
C4
1
.1
C48
.1
u
C2
.1u
C9
.1
u
C3
.1
u
C4
.1
u
C5
.1u
C31
1000uf,6.3
C39
.1u
C18
.1u
C35
.1u
C47
.1u
C27
0
R28
0
R29
0
R30
0
R31
.1u
C49
22
R8
3k
R32
10K
R33
.1u C50
1000uf,6.3
C51
D8
30BQ015
PID1103-1u
L7
JMP1
JMP2
SC1146
U2
12