Preliminary
RT9602
Dual Channel Synchronous-Rectified Buck MOSFET Driver
General Description
The RT9602 is a, twin power channel MOSFET driver
specifically designed to drive four power N-Channel
MOSFETs in a synchronous-rectified buck converter
topology.
These
drivers
combined
with
a
RT9237/RT9241 series of Multi-Phase Buck PWM
controller provide a complete core voltage regulator
solution for advanced microprocessors.
The RT9602 can provide flexible gate driving for both
high side and low side drivers. This gives more
flexibility of MOSFET selection.
The output drivers in the RT9602 have the capability
to drive a 3000pF load with a 40ns propagation delay
and 80ns transition time. This device implements
bootstrapping on the upper gates with only a single
external capacitor required for each power channel.
This reduces implementation complexity and allows
the use of higher performance, cost effective, N-
Channel
MOSFETs.
Adaptive
shoot-through
protection is integrated to prevent both MOSFETs
from conducting simultaneously.
The RT9602 can detect high side MOSFET drain-to-
source electrical short at power on and pull the 12V
power by low side MOS and cause power supply to
go into over current shutdown to prevent damage of
CPU.
Features
Drives Four N-Channel MOSFETs
Adaptive Shoot-Through Protection
Internal Bootstrap Devices
Small 14-Lead SOIC Package
5V to 12V Gate-Drive Voltages for Optimal
Efficiency
Tri-State Input for Bridge Shutdown
Supply Under-Voltage Protection
Power ON Over-Voltage Protection
Applications
Core Voltage Supplies for Intel Pentium 4 and
AMD Athlon
TM
Microprocessors
High Frequency Low Profile DC-DC Converters
High Current Low Voltage DC-DC Converters
Pin Configurations
Part Number
RT9602CS
(Plastic SOP-14)
PWM1
PWM2
GND
LGATE1
PVCC
PGND
LGATE2
1
2
3
4
5
6
7
Pin Configurations
TOP VIEW
14
13
12
11
10
9
8
VCC
PHASE1
UGATE1
BOOT1
BOOT2
UGATE2
PHASE2
Ordering Information
RT9602
Package type
S : SOP-14
Operating temperature range
C: Commercial standard
DS9602-00 January 2002
www.richtek-ic.com.tw
1
RT9602
Pin Description
Pin No. Pin Name
1
2
3
4
5
6
7
8
9
10
11
12
13
14
PWM1
PWM2
GND
LGATE1
PVCC
PGND
LGATE2
PHASE2
UGATE2
BOOT2
BOOT1
UGATE1
PHASE1
VCC
Channel 1 PWM Input
Channel 2 PWM Input
Ground Pin
Preliminary
Pin Function
Lower Gate Drive of Channel 1
Upper and Lower Gate Driver Power Rail
Lower Gate Driver Ground Pin
Lower Gate Drive of Channel 2
Connect this pin to phase point of channel 2.
Phase point is the connection point of high side MOSFET source and low side MOSFET drain
Upper Gate Drive of Channel 2
Floating Bootstrap Supply Pin of Channel 2
Floating Bootstrap Supply Pin of Channel 1
Upper Gate Drive of Channel 1
Connect this pin to phase point of channel 1.
Phase point is the connection point of high side MOSFET source and low side MOSFET drain
Control Logic Power Supply
www.richtek-ic.com.tw
DS9602-00 January 2002
2
Preliminary
Function Block Diagram
VCC
Internal
5V
PVCC
RT9602
BOOT1
19K
PWM1
19K
Power-on OVP
PVCC
Shoot-through
Protection
UGATE1
PHASE1
Shoot-through
Protection
LGATE1
PGND
PVCC
PGND
BOOT2
UGATE2
PHASE2
Control
Logic
Internal
5V
19K
PWM2
19K
Shoot-through
Protection
GND
Power-on OVP
Shoot-through
Protection
PVCC
LGATE2
PGND
DS9602-00 January 2002
www.richtek-ic.com.tw
3
RT9602
Absolute Maximum Ratings
Supply Voltage (VCC)
Supply Voltage (PVCC)
BOOT Voltage (V
BOOT
-V
PHASE
)
Input Voltage (VPWM)
UGATE
LGATE
Package Thermal Resistance
SOP-14,
θ
JA
Ambient Temperature
Junction Temperature
Storage Temperature Range
Lead Temperature (Soldering, 10 sec.)
ESD Level
HBM
MM
Preliminary
15V
VCC + 0.3V
15V
GND–0.3V to 7V
V
PHASE
-0.3V to V
BOOT
+0.3V
GND-0.3V to V
PVCC
+0.3V
160°C /W
0°C ~ 70°C
0°C ~ 125°C
-40°C ~ 150°C
260°C
2KV
200V
Electrical Characteristics
Parameter
VCC Supply Current
Bias Supply Current
Power Supply Current
Power-On Reset
VCC Rising Threshold
VCC Falling Threshold
PWM Input
Maximum Input Current
PWM Floating Voltage
PWM Rising Threshold
PWM Falling Threshold
UGATE Rise Time
LGATE Rise Time
UGATE Fall Time
LGATE Fall Time
UGATE Turn-Off Propagation Delay
LGATE Turn-Off Propagation Delay
Shutdown Window
V
PVCC
= V
VCC
= 12V, 3nF load
V
PVCC
= V
VCC
= 12V, 3nF load
V
PVCC
= V
VCC
= 12V, 3nF load
V
PVCC
= V
VCC
= 12V, 3nF load
V
VCC
= V
PVCC
= 12V, 3nF load
V
VCC
= V
PVCC
= 12V, 3nF load
V
PWM
= 0 or 5V
Vcc=12V
--
--
--
--
--
--
--
--
--
--
1.1
200
1.9
3.7
1.1
30
30
40
30
60
45
--
--
--
--
--
--
--
--
--
--
--
3.7
µA
V
V
V
ns
ns
ns
ns
ns
ns
V
9.1
7.5
9.6
8.1
10
8.5
V
V
I
VCC
I
PVCC
f
PWM
= 250KHz, V
PVCC
= 12V,
Cboot = 0.1µF, Rphase = 20Ω
f
PWM
= 250kHz, V
PVCC
= 12V,
Cboot = 0.1µF, Rphase = 20Ω
--
--
3
8
--
--
mA
mA
Symbol
Test Conditions
Min
Typ
Max
Units
To be continued
www.richtek-ic.com.tw
DS9602-00 January 2002
4
Preliminary
Parameter
Output
Upper Drive Source
Upper Drive Sink
Lower Drive Source
Lower Drive Sink
R
UGATE
V
VCC
= 12V, V
PVCC
= 12V
R
UGATE
V
VCC
= 12V, V
PVCC
= 12V
R
LGATE
V
VCC
= 12V, V
PVCC
= 12V
R
LGATE
V
VCC
= V
PVCC
= 12V
--
--
--
--
1.5
1.45
1.6
0.75
Symbol
Test Conditions
Min
Typ
RT9602
Max
--
2
--
1
Units
Ω
Ω
Ω
Ω
Operation Descriptions
The RT9602 has power on protection function which
held UGATE and LGATE low before V
CC
up across
the rising threshold voltage. After the initialization, the
PWM signal takes the control. The rising PWM signal
first forces the LGATE signal turns low then UGATE
signal is allowed to go high just after a non-
overlapping time to avoid shoot-through current. The
falling of PWM signal first forces UGATE to go low.
When
UGATE
and
PHASE
signal
reach
a
predetermined low level, LGATE signal is allowed to
turn high. The non-overlapping function is also
presented between UGATE and LGATE signal
transient.
The PWM signal is recognized as high if above rising
threshold and as low if below falling threshold. Any
signal level in this window is considered as tri-state,
which causes turn-off of both high side and low-side
MOSFET.
When
PWM
input
is
floating
(not
connected), internal divider will pull the PWM to 1.9V
to give the controller a recognizable level. The
maximum sink/source capability of internal PWM
reference is 60µA.
The PVCC pin provides flexibility of both high side
and low side MOSFET gate drive voltages. If 8V, for
example, is applied to PVCC, then high side
MOSFET
gate
drive
is
8V-1.5V(approximately,
internal diode plus series resistance voltage drop).
The low side gate drive voltage is exactly 8V.
The RT9602 implements a power on over-voltage
protection function. If the PHASE voltage exceeds
1.5V at power on, the LGATE would be turn on to pull
the PHASE low until the PHASE voltage goes below
1.5V. Such function can protect the CPU from
damage by some short condition happened before
power on, which is sometimes encountered in the
M/B manufacturing line.
DS9602-00 January 2002
www.richtek-ic.com.tw
5
