商品詳情
ISL95808
High Voltage Synchronous Rectified Buck MOSFET Driver
DATASHEET
The ISL95808 is a high frequency, dual MOSFET driver with low
shutdown current, optimized to drive two N-Channel power
MOSFETs in a synchronous-rectified buck converter topology. It
is especially suited for mobile computing applications that
require high efficiency and excellent thermal performance. The
driver, combined with an Intersil multiphase Buck PWM
controller, forms a complete single-stage core-voltage
regulator solution for advanced mobile microprocessors.
The ISL95808 features a 4A typical sinking current for the
lower gate driver. This current is capable of holding the lower
MOSFET gate off during the rising edge of the phase node. This
prevents shoot-through power loss caused by the high dv/dt of
phase voltages. The operating voltage matches the 30V
breakdown voltage of the MOSFETs commonly used in mobile
computer power supplies.
The ISL95808 also features a three-state PWM input. This
PWM input, working together with Intersil’s multiphase PWM
controllers, will prevent negative voltage output during CPU
shutdown. This feature eliminates a protective Schottky diode
usually seen in microprocessor power systems.
MOSFET gates can be efficiently switched up to 2MHz using
the ISL95808. Each driver is capable of driving a 3000pF load
with propagation delays of 8ns and transition times under
10ns. Bootstrapping is implemented with an internal Schottky
diode. This reduces system cost and complexity, while allowing
for the use of higher performance MOSFETs. Adaptive
shoot--through protection is integrated to prevent both
MOSFETs from conducting simultaneously.
A diode emulation feature is integrated in the ISL95808 to
enhance converter efficiency at light load conditions. This
feature also allows for monotonic start-up into prebiased
outputs. When diode emulation is enabled, the driver will allow
discontinuous conduction mode by detecting when the
inductor current reaches zero and subsequently turning off the
low-side MOSFET gate.
The ISL95808 also features very low shutdown supply current
(5V, 3μA) to ensure the low power consumption.
Features
? Dual MOSFET drivers for synchronous rectified bridge
? Adaptive shoot-through protection
? 0.5Ω ON-resistance and 4A sink current capability
? Supports high switching frequency up to 2MHz
- Fast output rise and fall time
- Low propagation delay
? Three-state PWM input for power stage shutdown
? Internal bootstrap Schottky diode
? Low shutdown supply current (5V, 3μA)
? Diode emulation for enhanced light-load efficiency and
prebiased start-up applications
? VCC POR (Power-On Reset) feature integrated
? Low three-state shutdown hold-off time (typical 160ns)
? DFN package
? Pb-free (RoHS compliant)
Applications
? Core voltage supplies for Intel® and AMD? mobile
microprocessors
? High frequency low profile DC/DC converters
? High current low output voltage DC/DC converters
? High input voltage DC/DC converters
Related Literature
? TB389, “PCB Land Pattern Design and Surface Mount
Guidelines for MLFP Packages”
? TB447, “Guidelines for Preventing Boot-to-Phase Stress on
Half-Bridge MOSFET Driver ICs”
VCC
PWM
10kΩ
CONTROL
LOGIC
SHOOTTHROUGH
PROTECTION
BOOT
UGATE
PHASE
LGATE
GND
VCC
FCCM
THERMAL PAD
FIGURE 1. BLOCK DIAGRAM
ISL95808
FN8689 Rev 2.00 Page 2 of 9
May 25, 2016
Pin Configuration
ISL95808
(8 LD 2x2 DFN)
TOP VIEW
Ordering Information
PART NUMBER
(Notes 1, 2, 3)
PART
MARKING
TEMP. RANGE
(°C)
TAPE AND REEL
(UNITS)
PACKAGE
(RoHS Compliant)
PKG.
DWG. #
ISL95808HRZ-T 08 -10 to +100 6k 8 Ld 2x2 DFN L8.2x2D
ISL95808IRZ-T 08I -40 to +100 6k 8 Ld 2x2 DFN L8.2x2D
NOTES:
1. Please refer to TB347 for details on reel specifications.
2. These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte
tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Intersil Pbfree products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
3. For Moisture Sensitivity Level (MSL), please see product information page for ISL95808. For more information on MSL, please see tech brief TB363.
1
6 VCC
LGATE
PWM
GND 5
6
6 PHASE
7 FCCM
UGATE 8
BOOT 2
3
4
Pin Descriptions
PIN NUMBER PIN NAME DESCRIPTION
1 UGATE The UGATE pin is the upper gate drive output. Connect to the gate of high-side power N-Channel MOSFET.
2 BOOT BOOT is the floating bootstrap supply pin for the upper gate drive. Connect the bootstrap capacitor between this
pin and the PHASE pin. The bootstrap capacitor provides the charge to turn on the upper MOSFET. See “Internal
Bootstrap Diode” on page 7 for guidance in choosing the appropriate capacitor value.
3 PWM The PWM signal is the control input for the driver. The PWM signal can enter three distinct states during operation.
See “Three-State PWM Input” on page 6 for further details. Connect this pin to the PWM output of the controller.
4 GND GND is the ground pin for the IC.
5 LGATE LGATE is the lower gate drive output. Connect to gate of the low-side power N-Channel MOSFET.
6 VCC Connect the VCC pin to a +5V bias supply. Place a high quality bypass capacitor from this pin to GND. The VCC
pin of the driver(s) and related VCC or +5V bias supply pin of the Intersil controller must share a common +5V
supply.
7 FCCM The FCCM pin enables or disables diode emulation. When FCCM is LOW, diode emulation is allowed. When
FCCM is HIGH, continuous conduction mode is forced. See “Diode Emulation” on page 6 for more detail. High
impedance on the input of FCCM will shut down ISL95808.
8 PHASE Connect the PHASE pin to the source of the upper MOSFET and the drain of the lower MOSFET. This pin provid