Datasheet ADP3414JR Datasheet (Analog Devices)

Dual Bootstrapped

a

FEATURES
All-In-One Synchronous Buck Driver
Bootstrapped High-Side Drive
One PWM Signal Generates Both Drives
Anticross-Conduction Protection Circuitry
Pulse-by-Pulse Disable Control

APPLICATIONS
Mobile Computing CPU Core Power Converters
Multiphase Desktop CPU Supplies
Single-Supply Synchronous Buck Converters
Standard-to-Synchronous Converter Adaptations

GENERAL DESCRIPTION

The ADP3414 is a dual MOSFET driver optimized for driving
two N-channel MOSFETs which are the two switches in a
nonisolated synchronous buck power converter. Each of the
drivers is capable of driving a 3000 pF load with a 20 ns propa­gation delay and a 30 ns transition time. One of the drivers can
be bootstrapped, and is designed to handle the high-voltage
slew rate associated with “floating” high-side gate drivers.
The ADP3414 includes overlapping drive protection (ODP)
to prevent shoot-through current in the external MOSFETs.

The ADP3414 is specified over the commercial temperature
range of 0°C to 70°C and is available in an 8-lead SOIC package.

ADP3414

VCC

MOSFET Driver

ADP3414

FUNCTIONAL BLOCK DIAGRAM

VCC

IN

OVERLAP

PROTECTION

CIRCUIT

ADP3414

7V

D1

BST

12V

BST

DRVH

SW

DRVL

PGND

IN

DELAY

1V

Figure 1. General Application Circuit

REV. 0

Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices.

C

BST

DRVH

SW

+1V

DRVL

PGND

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © Analog Devices, Inc., 2001

Q1

Q2

1

ADP3414–SPECIFICATIONS

Parameter Symbol Conditions Min Typ Max Unit

SUPPLY

Supply Voltage Range VCC 4.15 7.5 V
Quiescent Current ICC

PWM INPUT

Input Voltage High
Input Voltage Low

2

2

HIGH-SIDE DRIVER

Output Resistance, Sourcing Current V

Output Resistance, Sinking Current V

3

Transition Times

Propagation Delay

(See Figure 2) tr

3, 4

(See Figure 2) tpdh

LOW-SIDE DRIVER

Output Resistance, Sourcing Current VCC = 5 V 3.0 5.0 Ω

Output Resistance, Sinking Current VCC = 5 V 1.5 3.0 Ω

3

Transition Times

Propagation Delay

NOTES

1

All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.

2

Logic inputs meet typical CMOS I/O conditions for source/sink current (~1 µA).

3

AC specifications are guaranteed by characterization, but not production tested.

4

For propagation delays, “tpdh” refers to the specified signal going high; “tpdl” refers to it going low.

Specifications subject to change without notice.

(See Figure 2) tr

3, 4

(See Figure 2) tpdh

DRVH

tf

DRVH

tpdl

DRVL

tf

DRVL

tpdl

Q

DRVH

DRVH

DRVL

DRVL

(TA = 0ⴗC to 70ⴗC, VCC = 7 V, BST = 4 V to 26 V, unless otherwise noted.)

12 mA

2.3 V

0.8 V

– VSW = 5 V 3.0 5.0 Ω

BST

– VSW = 7 V 2.0 3.5 Ω

V

BST

– VSW = 5 V 1.25 2.5 Ω

BST

V

– VSW = 7 V 1.0 2.5 Ω

BST

V

– VSW = 7 V, C

BST

V

– VSW = 7 V, C

BST

V

– V

BST

V

– V

BST

SW

= 7 V 65 86 ns

SW

= 7 V 21 32 ns

= 3 nF 36 47 ns

LOAD

= 3 nF 20 30 ns

LOAD

VCC = 7 V 2.0 3.5 Ω

VCC = 7 V 1.0 2.5 Ω
VCC = 7 V, C
VCC = 7 V, C

= 3 nF 27 35 ns

LOAD

= 3 nF 19 26 ns

LOAD

VCC = 7 V 30 35 ns
VCC = 7 V 15 25 ns

–2–

REV. 0

ADP3414

IN

VCC

BST

NC

DRVH

SW

DRVL

PGND

8

7

6

5

NC = NO CONNECT

ADP3414

TOP VIEW

(Not To Scale)

1

2

3

4

ABSOLUTE MAXIMUM RATINGS*

VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +8 V

BST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +30 V

BST to SW . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +8 V

SW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –5.0 V to +25 V

IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to VCC + 0.3 V

Model Range Description Option

ADP3414JR 0°C to 70°C 8-Lead Standard SO-8

ORDERING GUIDE

Temperature Package Package

Small Outline (SOIC)

Operating Ambient Temperature Range . . . . . . . 0°C to 70°C

Operating Junction Temperature Range . . . . . . 0°C to 125°C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155°C/W

θ

JA

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40°C/W

θ

JC

PIN CONFIGURATION

Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C

Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . . 300°C

*This is a stress rating only; operation beyond these limits can cause the device to

be permanently damaged. Unless otherwise specified, all voltages are referenced
to PGND.

PIN FUNCTION DESCRIPTIONS

Pin Mnemonic Function

1 BST Floating Bootstrap Supply for the Upper MOSFET. A capacitor connected between BST and SW pins

holds this bootstrapped voltage for the high-side MOSFET as it is switched. The capacitor should be

chosen between 100 nF and 1 ␮F.
2 IN TTL-level Input Signal, which has primary control of the drive outputs.
3 NC No Connection.
4 VCC Input Supply. This pin should be bypassed to PGND with ~1 µF ceramic capacitor.
5 DRVL Synchronous Rectifier Drive. Output drive for the lower (synchronous rectifier) MOSFET.
6 PGND Power Ground. Should be closely connected to the source of the lower MOSFET.
7 SW This pin is connected to the buck-switching node, close to the upper MOSFET’s source. It is the floating

return for the upper MOSFET drive signal. It is also used to monitor the switched voltage to prevent turn-

on of the lower MOSFET until the voltage is below ~1 V. Thus, according to operating conditions, the

high-low transition delay is determined at this pin.
8 DRVH Buck Drive. Output drive for the upper (buck) MOSFET.

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although

WARNING!

the ADP3414 features proprietary ESD protection circuitry, permanent damage may occur on
devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are
recommended to avoid performance degradation or loss of functionality.

REV. 0

–3–

ESD SENSITIVE DEVICE

ADP3414

DRVL

IN

DRVL

tf

DRVL

tpdh

DRVHtrDRVH

tpdl

DRVH

tf

DRVH

tr

DRVL

tpdl

DRVH-SW

SW

V

TH

V

TH

tpdh

DRVL

1V

Figure 2. Nonoverlap Timing Diagram (Timing Is Referenced to the 90% and 10% Points Unless Otherwise Noted)

–4–

REV. 0

Typical Performance Characteristics–

ADP3414

T

DRVH

5V/DIV

R3

IN

R2

2V/DIV

R1

TA = 25ⴗC
VCC = 5V

DRVL

5V/DIV

40ns/DIV

TPC 1. DRVH Fall and DRVL Rise
Times

35

30

25

20

15

TIME – ns

10

5

0

0

DRVL @ VCC = 5V

DRVH @ VCC = 5V

25

JUNCTION TEMPERATURE – ⴗC

DRVL @ VCC = 7V

DRVH @ VCC = 7V

50 75 100

125

TPC 4. DRVH and DRVL Fall Times
vs. Temperature

T

TA = 25ⴗC

VCC = 5V

R3

DRVL

2V/DIV

R2

IN

2V/DIV

R1

DRVH

5V/DIV

40ns/DIV

TPC 2. DRVL Fall and DRVH Rise
Times

55

50

45

40

DRVH @ VCC = 7V

35

30

TIME – ns

25

20

15

10

1.0

DRVH @ VCC = 5V

DRVL @ VCC = 5V

DRVL @ VCC = 7V

2.0 3.0 4.0 5.0

LOAD CAPACITANCE – nF

TPC 5. DRVH and DRVL Rise Times
vs. Load Capacitance

50

C

= 3nF

LOAD

45

DRVH @ VCC = 5V

40

35

TIME – ns

30

25

20

025

DRVL @ VCC = 5V

JUNCTION TEMPERATURE – ⴗC

DRVH @ VCC = 7V

DRVL @ VCC = 7V

50 75 100

125

TPC 3. DRVH and DRVL Rise Times
vs. Temperature

37

32

DRVL @ VCC = 7V

27

22

TIME – ns

17

12

7

DRVL @ VCC = 5V

2.0 3.0 4.0 5.0

1.5 2.5 3.5 4.5

1.0
LOAD CAPACITANCE – nF

DRVH @ VCC = 5V

DRVH @ VCC = 7V

TPC 6. DRVH and DRVL Fall Times
vs. Load Capacitance

35

TA = 25ⴗC

= 3nF

C

30

LOAD

SUPPLY CURRENT – mA

25

20

15

10

5

0

0

VCC = 7V

200

400 600 800

IN FREQUENCY – kHz

VCC = 5V

TPC 7. Supply Current vs.
Frequency

1000 1200 1400

8.5

8.0

VCC = 7V

7.5

7.0

6.5

6.0

SUPPLY CURRENT – mA

5.0

VCC = 5V

5.5

0

25 50 75

JUNCTION TEMPERATURE – ⴗC

TPC 8. Supply Current vs.
Temperature

C

LOAD

f

= 250kHz

IN

100

= 3nF

125

REV. 0

–5–

ADP3414

THEORY OF OPERATION

The ADP3414 is a dual MOSFET driver optimized for driving
two N-channel MOSFETs in a synchronous buck converter
topology. A single PWM input signal is all that is required to
properly drive the high-side and the low-side FETs. Each driver
is capable of driving a 3 nF load.

A more detailed description of the ADP3414 and its features
follows. Refer to the Functional Block Diagram.

Low-Side Driver

The low-side driver is designed to drive low R

DS(ON)

N-channel

MOSFETs. The maximum output resistance for the driver is

3.5 Ω for sourcing and 2.5 Ω for sinking gate current. The low
output resistance allows the driver to have 20 ns rise and fall
times into a 3 nF load. The bias to the low-side driver is inter­nally connected to the VCC supply and PGND.

When the driver is enabled, the driver’s output is 180 degrees
out of phase with the PWM input. When the ADP3414 is dis­abled, the low-side gate is held low.

High-Side Driver

The high-side driver is designed to drive a floating low R

DS(ON)

N-channel MOSFET. The maximum output resistance for the
driver is 3.5 Ω for sourcing and 2.5 Ω for sinking gate cur­rent. The low output resistance allows the driver to have 30 ns
rise and fall times into a 3 nF load. The bias voltage for the
high-side driver is developed by an external bootstrap supply
circuit, which is connected between the BST and SW pins.

The bootstrap circuit comprises a diode, D1, and bootstrap
capacitor, C

. When the ADP3414 is starting up, the SW pin

BST

is at ground, so the bootstrap capacitor will charge up to VCC
through D1. When the PWM input goes high, the high-side
driver will begin to turn the high-side MOSFET, Q1, ON by
pulling charge out of C
rise up to V

, forcing the BST pin to VIN + V

IN

. As Q1 turns ON, the SW pin will

BST

C(BST)

, which is
enough gate to source voltage to hold Q1 ON. To complete the
cycle, Q1 is switched OFF by pulling the gate down to the volt­age at the SW pin. When the low-side MOSFET, Q2, turns
ON, the SW pin is pulled to ground. This allows the bootstrap
capacitor to charge up to VCC again.

The high-side driver’s output is in phase with the PWM input.
When the driver is disabled, the high-side gate is held low.

Overlap Protection Circuit

The Overlap Protection Circuit (OPC) prevents both of the main
power switches, Q1 and Q2, from being ON at the same time.
This is done to prevent shoot-through currents from flowing
through both power switches and the associated losses that can
occur during their ON-OFF transitions. The Overlap Protection
Circuit accomplishes this by adaptively controlling the delay from
Q1’s turn OFF to Q2’s turn ON, and by internally setting the
delay from Q2’s turn OFF to Q1’s turn ON.

To prevent the overlap of the gate drives during Q1’s turn OFF
and Q2’s turn ON, the overlap circuit monitors the voltage at the
SW pin. When the PWM input signal goes low, Q1 will begin to
turn OFF (after a propagation delay), but before Q2 can turn ON
the overlap protection circuit waits for the voltage at the SW pin
to fall from V

to 1 V. Once the voltage on the SW pin has fallen

IN

to 1 V, Q2 will begin turn ON. By waiting for the voltage on the
SW pin to reach 1 V, the overlap protection circuit ensures that
Q1 is OFF before Q2 turns on, regardless of variations in tem­perature, supply voltage, gate charge, and drive current.

To prevent the overlap of the gate drives during Q2’s turn OFF
and Q1’s turn ON, the overlap circuit provides a internal delay
that is set to 50 ns. When the PWM input signal goes high, Q2
will begin to turn OFF (after a propagation delay), but before
Q1 can turn ON the overlap protection circuit waits for the
voltage at DRVL to drop to around 10% of VCC. Once the
voltage at DRVL has reached the 10% point, the overlap protec­tion circuit will wait for a 20 ns typical propagation delay. Once
the delay period has expired, Q1 will begin turn ON.

APPLICATION INFORMATION
Supply Capacitor Selection

For the supply input (VCC) of the ADP3414, a local bypass
capacitor is recommended to reduce the noise and to supply some
of the peak currents drawn. Use a 1 µF, low ESR capacitor.
Multilayer ceramic chip (MLCC) capacitors provide the best
combination of low ESR and small size and can be obtained from
the following vendors:

Murata GRM235Y5V106Z16 www.murata.com

Taiyo­Yuden EMK325F106ZF www.t-yuden.com

Tokin C23Y5V1C106ZP www.tokin.com

Keep the ceramic capacitor as close as possible to the ADP3414.

Bootstrap Circuit

The bootstrap circuit uses a charge storage capacitor (C

BST

) and a
Schottky diode, as shown in Figure 1. Selection of these compo­nents can be done after the high-side MOSFET has been chosen.

The bootstrap capacitor must have a voltage rating that is able
to handle the maximum battery voltage plus 5 volts. A minimum
50 V rating is recommended. The capacitance is determined
using the following equation:

Q

GATE

=

V

∆

BST

where, Q
and ∆V

BST

C

BST

is the total gate charge of the high-side MOSFET,

GATE

is the voltage droop allowed on the high-side MOSFET
drive. For example, the IRF7811 has a total gate charge of about
20 nC. For an allowed droop of 200 mV, the required boot­strap capacitance is 100 nF. A good quality ceramic capacitor
should be used.

A Schottky diode is recommended for the bootstrap diode due
to its low forward drop, which maximizes the drive available for
the high-side MOSFET. The bootstrap diode must have a mini­mum 40 V rating to withstand the maximum battery voltage
plus 5 V. The average forward current can be estimated by:

fQI ×≈

MAXGATEF(AVG)

where f

is the maximum switching frequency of the control-

MAX

ler. The peak surge current rating should be checked in-circuit,
since this is dependent on the source impedance of the 5 V
supply, and the ESR of C

BST

.

–6–

REV. 0

ADP3414

Printed Circuit Board Layout Considerations

Use the following general guidelines when designing printed
circuit boards:

1. Trace out the high-current paths and use short, wide traces
to make these connections.

2. Connect the PGND pin of the ADP3414 as close as possible
to the source of the lower MOSFET.

3. The VCC bypass capacitor should be located as close as
possible to VCC and PGND pins.

34.0k⍀

C

OC

1.4nF

1.1k⍀

11.5k⍀

V

R

12V

RTN

IN

R

A

Z

R

B

100pF

V

C2

IN

FROM

CPU

270␮F ⴛ 4

OS–CON 16V

U1

ADP3160

VID4 VCC

1

VID3

2

VID2

3

VID1

4

VID0

5

6

COMP

PWRGND

FB

7

CT

C1

150pF

R1

1k⍀

C4

4.7␮F

REF

CS–

PWM1

PWM2

CS+

GND

C15C14C13C12

10⍀

R6

C21

15nF

ZMM5236BCT

C22

16

1nF

15

14

13

12

11

10

98

C26

4.7␮F

R5

2.4k⍀

Z1

1␮F

R7

20⍀

C23

C24

10␮F

10␮F

MBR052LTI

Q5
2N3904

C5

1␮F

D2

MBR052LTI

C6

Typical Application Circuits

The circuit in Figure 3 shows how two drivers can be com­bined with the ADP3160 to form a total power conversion
solution for V

CC(CORE)

generation in a high-current Intel CPU
computer. Figure 4 gives a similar application circuit for a
45 A AMD processor.

R4

4m⍀

U2

SW

PGND

DRVL

SW

PGND

DRVL

1␮F

C10
1␮F

C9

8

7

6

5

8

7

6

5

Q1
FDB7030L

Q2
FDB8030L

OS–CON 2.5V

11m⍀ ESR (EACH)

+ +

+

C11 C16 C17 C18 C19 C20 C27 C28

Q3
FDB7030L

Q4
FDB8030L

L1

600nH

1200␮F ⴛ 8

+ +

L2

600nH

+ +

V

CC (CORE)

1.1V – 1.85V

53.4A

+

V

RTN

CC (CORE)

D1

ADP3414

1

BST DRVH

2

IN

NC

3

VCC

4

U3

ADP3414

1

BST DRVH

2

IN

NC

3

VCC

4

NC = NO CONNECT

REV. 0

Figure 3. 53.4 A Intel CPU Supply Circuit

–7–

ADP3414

V

RTN

IN

12V V

V

CC

R

6.98k⍀

C

OC

4.7nF

R

Z

750⍀

R

14.0k⍀

100pF

A

B

V

IN

5V

12V

RTN

C2

CC

FROM

CPU

1000␮F ⴛ 6

RUBYCON ZA SERIES

C4

4.7␮F

U1

ADP3160

VID4 VCC

1

2

3

4

5

6

7

8

C1

150pF

R1

1k⍀

VID3

VID2

VID1

VID0

COMP

FB

CT

REF

CS–

PWM1

PWM2

CS+

PWRGD

GND

C15C14C13C12

10⍀

R6

16

15

14

13

12

11

10

9

C24 C25

C21

15nF

C22
1nF

C26

4.7␮F

R5

2.4k⍀

Z1

ZMM5236BCT

C6

1␮F

R7

20⍀

MBR052LTI

Q5
2N3904

MBR052LTI

C5
1␮F

D2

D1

R4

5m⍀

C29

C30

10␮F

10␮F

U2

ADP3414

1

BST DRVH

2

IN

SW

NC

3

PGND

DRVL

VCC

4

C10
1␮F

U3

ADP3414

1

BST DRVH

2

IN

SW

NC

3

PGND

DRVL

VCC

4

NC = NO CONNECT

C9

1␮F

8

7

6

5

8

7

6

5

Q1
FDB7030L

Q2
FDB7045L

+ +

L1

600nH

1000␮F ⴛ 8

RUBYCON ZA SERIES

24m⍀ ESR (EACH)

+ +

+

+ +

C11 C16 C17 C18 C19 C20 C27 C28

Q3
FDB7030L

Q4
FDB7045L

L2

600nH

V

CC (CORE)

1.1V – 1.85V
45A

+

V
RTN

C02400–1–7/01(0)

CC (CORE)

Figure 4. 45 A Athlon Duron CPU Supply Circuit

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

8-Lead Small Outline Package

(R-8A)

0.1968 (5.00)

0.1890 (4.80)

0.1574 (4.00)

0.1497 (3.80)

PIN 1

0.0098 (0.25)

0.0040 (0.10)

SEATING

85

0.0500 (1.27)

PLANE

0.2440 (6.20)

0.2284 (5.80)

41

BSC

0.0192 (0.49)

0.0138 (0.35)

0.102 (2.59)

0.094 (2.39)

0.0098 (0.25)

0.0075 (0.19)

0.0196 (0.50)

0.0099 (0.25)

8ⴗ
0ⴗ

0.0500 (1.27)

0.0160 (0.41)

ⴛ 45ⴗ

PRINTED IN U.S.A.

–8–

REV. 0