High Speed, Combi-Sense
®
, Synchronous
MOSFET Driver for Mobile Applications
POWER MANAGEMENT
Description
The SC1211VX is a high speed, Combi-Sense®, dual out-
put driver designed to drive high-side and low-side
MOSFETs in a synchronous Buck converter. These
drivers combined with Combi-Sense® PWM controllers,
such as Semtech SC2643VX or SC2643, provide a
cost effective multi-phase voltage regulator for advanced
microprocessors.
The Combi-Sense® is a technique to sense the inductor
current for peak current mode control of voltage regula-
tor without using sensing resistor. It provides the follow-
ing advantages:
- No costly precision sensing resistor
- Lossless current sensing
- High level noise free signal
- Fast response
- Suitable for wide range of duty cycle
- Only two small signal components (third optional)
The detailed explanation of the technique can be found
in the Applications Information section.
A 30ns max propagation delay from input transition to
the gate of the power FET’s guarantees operation at high
switching frequencies. Internal overlap protection circuit
prevents shoot-through from Vin to PGND in the main
and synchronous MOSFETs. The adaptive overlap pro-
tection circuit ensures the bottom FET does not turn on
until the top FET source has reached 1V, to prevent cross-
conduction.
High current drive capability allows fast switching, thus
reducing switching losses at high (up to 1.5MHz) frequen-
cies without causing thermal stress on the driver.
Under-voltage-lockout and over-temperature shutdown
features are included for proper and safe operation.
Timed latches and improved robustness are built into
the housekeeping functions such as the Under Voltage
Lockout and adaptive Shoot-through protection circuitry
to prevent false triggering and to assure safe operation.
The SC1211VX is offered in a Power SOIC-8L package.
SC1211VX
Features
u
High efficiency
u
High peak drive current
u
Adaptive non-overlapping gate drives provide
u
u
u
u
u
u
u
u
u
shoot-through protection
Support
Combi-Sense®
and VID-on-fly operations
Fast rise and fall times (15ns typical with 3000pf
load)
Ultra-low (<30ns) propagation delay (BG going low)
Floating top gate drive
Crowbar function for over voltage protection
High frequency (to 1.5 MHz) operation allows use
of small inductors and low cost ceramic capacitors
Under-voltage-lockout
Low quiescent current
Power SOIC-8L package, fully RoHS and WEEE
compliant
Applications
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Intel Pentium
®
processor power supplies
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AMD Athlon
TM
and AMD-K8
TM
processor power
supplies
u
High efficiency portable and notebook computer
s
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Battery powered application
s
u
High current low voltage DC-DC converter
s
October 12, 2005
1
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SC1211VX
POWER MANAGEMENT
Absolute Maximum Ratings
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.
Parameter
V
CC
Supply Voltage
VIN to PGND
BST to DRN
BST to PGND
BST to PGND Pulse
DRN to PGND
DRN to PGND Pulse
VPN to PGND
PWM Input
Continuous Power Dissipation
Thermal Resistance Junction to Case
Operating Junction Temperature Range
Storage Temperature Range
Lead Temperature (Soldering) 10 Sec.
Symbol
V
CC
V
IN
V
BST-DRN
V
BST-PGND
V
BST_PULSE
V
DRN-PGND
V
DRN_PULSE
V
PN
CO
P
D
θ
JC
T
J
T
STG
T
LEAD
Conditions
Maximum
10
30
10
36
Units
V
V
V
V
V
V
V
V
V
W
°C/W
°C
°C
°C
t
PULSE
< 100ns
41
-2 to 29
t
PULSE
< 100ns
-4 to 34
30
-0.3 to 5
T
A
= 25°C, T
J
=125°C
2.56
8
0 to +125
-65 to +150
300
NOTE:
(1) This device is ESD sensitive. Use of standard ESD handling precautions is required.
Electrical Characteristics
Unless specified: T
A
= 25°C; V
CC
= 5V
Parameter
Pow er Supply
Supply Voltage
Quiescent Current, Operating
Under Voltage Lockout
Start Threshold
Hysteresis
Symbol
Conditions
Min
Typ
Max
Units
V
CC
Iq_op
4.3
5
3.0
6.0
V
mA
V
CC_START
Vhys
UVLO
4
160
4.3
V
mV
2005 Semtech Corp.
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SC1211VX
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Unless specified: T
A
= 25°C; V
CC
= 5V
Parameter
CO
High Level Input Voltage
Low Level Input Voltage
Thermal Shutdow n
Over Temperature Trip Point
Hysteresis
High Side Driver (TG)
Output Impedance
Rise Time
Fall Time
Propagation Delay, TG Going High
Propagation Delay, TG Going Low
Low -Side Driver (BG)
Output Resistance
Rise Time
Fall Time
Propagation Delay, BG Going High
Propagation Delay, BG Going Low
Under-Voltage-Lockout Time Delay
V
CC
ramping up
V
CC
ramping down
Symbol
Conditions
Min
Typ
Max
Units
V
CO_H
V
CO_L
2.0
0.8
V
V
T
OTP
T
HYST
155
10
°C
°C
R
SRC_TG
R
SINK_TG
t
R_TG
t
F_TG
t
PDH_TG
t
PDL_TG
1.24
V
BST
- V
DRN
= 5V
CL = 3.3nF, V
BST
- V
DRN
= 5V
CL = 3.3nF, V
BST
- V
DRN
= 5V
V
BST
- V
DRN
= 5V
V
BST
- V
DRN
= 5V
0.86
8
8
20
25
1.8
1.3
Ohms
ns
ns
ns
ns
R
SRC_BG
R
SINK_BG
t
R_BG
t
F_BG
t
PDH_BG
t
PDL_BG
V
BST
- V
DRN
= 5V
CL = 3.3nF, V
BST
- V
DRN
= 5V
CL = 3.3nF, V
BST
- V
DRN
= 5V
V
BST
- V
DRN
= 5V
V
BST
- V
DRN
= 5V
1.28
0.6
8
4
20
25
1.7
1.2
Ohms
ns
ns
ns
ns
t
PDH_UVLO
t
PDL_UVLO
2
2
µs
µs
2005 Semtech Corp.
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