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FDS6984AS Rev A1(X)

FDS6984AS

Dual Notebook Power Supply N-Channel PowerTrench

SyncFET

™

General Description

The FDS6984AS is designed to replace two single

SO-8 MOSFETs and Schottky diode in synchronous

DC:DC power supplies that provide various peripheral

voltages for notebook computers and other battery

powered electronic devices. FDS6984AS contains two

unique 30V, N-channel, logic level, PowerTrench

MOSFETs designed to maximize power conversion

efficiency.

The high-side switch (Q1) is designed with specific

emphasis on reducing switching losses while the low-

side switch (Q2) is optimized to reduce conduction

losses. Q2 also includes a patented combination of a

MOSFET monolithically integrated with a Schottky

diode.

Features

• Q2: Optimized to minimize conduction losses

Includes SyncFET Schottky diode

8.5A, 30V R

DS(on)

max= 20 mΩ @ V

= 10V

DS(on)

max= 28 mΩ @ V

= 4.5V

• Q1: Optimized for low switching losses

Low gate charge (8nC typical)

5.5A, 30V R

DS(on)

max= 31 mΩ @ V

= 10V

DS(on)

max= 40 mΩ @ V

= 4.5V

SO-8

Absolute Maximum Ratings T

= 25°C unless otherwise noted

Symbol Parameter Q2 Q1 Units

DSS

Drain-Source Voltage 30 30 V

GSS

Gate-Source Voltage

±20 ±20

Drain Current - Continuous (Note 1a) 8.5 5.5 A

- Pulsed 30 20

Power Dissipation for Dual Operation 2 W

Power Dissipation for Single Operation (Note 1a) 1.6

(Note 1b)

(Note 1c)

0.9

, T

STG

Operating and Storage Junction Temperature Range –55 to +150

°C

Thermal Characteristics

θJA

Thermal Resistance, Junction-to-Ambient

(Note 1a) 78

°C/W

θJC

Thermal Resistance, Junction-to-Case

(Note 1) 40

°C/W

Package Marking and Ordering Information

Device Marking Device Reel Size Tape width Quantity

FDS6984AS FDS6984AS 13” 12mm 2500 units

FDS6984AS

• RoHS Compliant

May 2008

Summary of content (9 pages)

PAGE 1
May 2008 FDS6984AS Dual Notebook Power Supply N-Channel PowerTrench® SyncFET™ General Description Features The FDS6984AS is designed to replace two single SO-8 MOSFETs and Schottky diode in synchronous DC:DC power supplies that provide various peripheral voltages for notebook computers and other battery powered electronic devices. FDS6984AS contains two unique 30V, N-channel, logic level, PowerTrench MOSFETs designed to maximize power conversion efficiency.
PAGE 2
TA = 25°C unless otherwise noted Symbol Test Conditions Parameter Type Min Typ Max Units Off Characteristics BVDSS Drain-Source Breakdown Voltage VGS = 0 V, ID = 1 mA VGS = 0 V, ID = 250 µA Q2 Q1 IDSS Zero Gate Voltage Drain Current VDS = 24 V, VGS = 0 V Q2 Q1 Q2 2.
PAGE 3
Symbol (continued) Parameter Switching Characteristics TA = 25°C unless otherwise noted Test Conditions Type Min Typ Max Units (Note 2) td(on) Turn-On Delay Time tr Turn-On Rise Time td(off) Turn-Off Delay Time tf Turn-Off Fall Time td(on) Turn-On Delay Time tr Turn-On Rise Time td(off) Turn-Off Delay Time tf Turn-Off Fall Time Qg(TOT) Total Gate Charge, Vgs = 10V Qg Total Gate Charge, Vgs = 5V Qgs Gate-Source Charge Qgd Gate-Drain Charge Q2 Q1 Q2 Q1 Q2 Q1 Q2 Q1 Q2 Q1 Q2 Q1 Q
PAGE 4
FDS6984AS Typical Characteristics: Q2 2 30 VGS = 10V RDS(ON), NORMALIZED DRAIN-SOURCE ON-RESISTANCE ID, DRAIN CURRENT (A) 25 VGS = 3.0V 3.5V 4.0V 6.0V 4.5V 20 3.0V 15 10 5 2.5V 0 1.8 1.6 3.5V 1.4 4.0V 5.0V 6.0V 10V 1 0.8 0 0.5 1 1.5 2 VDS, DRAIN-SOURCE VOLTAGE (V) 2.5 3 0 Figure 1. On-Region Characteristics. 10 15 20 ID, DRAIN CURRENT (A) 25 30 0.06 ID = 8.5A VGS = 10V RDS(ON), ON-RESISTANCE (OHM) ID = 4.25A 1.45 1.3 1.15 1 0.85 0.7 0.05 0.04 TA = 125oC 0.03 0.
PAGE 5
800 f = 1MHz VGS = 0 V ID =8.5A 8 VDS = 10V CAPACITANCE (pF) VGS, GATE-SOURCE VOLTAGE (V) 10 20V 6 15V 4 600 Ciss 400 Coss 200 2 Crss 0 0 0 2 4 6 8 Qg, GATE CHARGE (nC) 10 12 0 Figure 7. Gate Charge Characteristics. 10 15 20 25 VDS, DRAIN TO SOURCE VOLTAGE (V) 30 Figure 8. Capacitance Characteristics. 50 100 P(pk), PEAK TRANSIENT POWER (W) RDS(ON) LIMIT 100µs ID, DRAIN CURRENT (A) 5 1ms 10 10ms 100ms 1s 10s 1 DC VGS = 10V SINGLE PULSE o RθJA = 135 C/W 0.1 TA = 25oC 0.
PAGE 6
FDS6984AS Typical Characteristics Q1 2.4 20 6.0V 16 ID, DRAIN CURRENT (A) 4.0V VGS = 3.0V 4.5V RDS(ON), NORMALIZED DRAIN-SOURCE ON-RESISTANCE VGS = 10V 3.5V 12 8 3.0V 4 2.5V 0.5 1 1.5 2 VDS, DRAIN-SOURCE VOLTAGE (V) 2.5 1.6 3.5V 1.4 4.0V 4.5V 5.0V 1.2 6.0V 10V 1 0 5 10 ID, DRAIN CURRENT (A) 15 20 Figure 12. On-Resistance Variation with Drain Current and Gate Voltage. 0.1 1.6 ID = 5.5A VGS = 10V RDS(ON), ON-RESISTANCE (OHM) RDS(ON), NORMALIZED DRAIN-SOURCE ON-RESISTANCE 1.
PAGE 7
FDS6984AS Typical Characteristics Q1 600 f = 1MHz VGS = 0 V ID = 5.5A 500 8 VDS = 10V CAPACITANCE (pF) VGS, GATE-SOURCE VOLTAGE (V) 10 20V 6 15V 4 2 400 300 Coss 200 100 Crss 0 0 0 2 4 6 Qg, GATE CHARGE (nC) 8 0 10 Figure 17. Gate Charge Characteristics. 5 10 15 VDS, DRAIN TO SOURCE VOLTAGE (V) 20 Figure 18. Capacitance Characteristics. 50 RDS(ON) LIMIT 10 10ms P(pk), PEAK TRANSIENT POWER (W) 100 100µs 1ms 100ms 1s 10s 1 DC VGS = 10V SINGLE PULSE RθJA = 135oC/W 0.
PAGE 8
FDS6984AS Typical Characteristics (continued) SyncFET Schottky Body Diode Characteristics Schottky barrier diodes exhibit significant leakage at high temperature and high reverse voltage. This will increase the power in the device. 3A/DIV IDSS, REVERSE LEAKAGE CURRENT (A) Fairchild’s SyncFET process embeds a Schottky diode in parallel with PowerTrench MOSFET. This diode exhibits similar characteristics to a discrete external Schottky diode in parallel with a MOSFET.
PAGE 9
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