IRF IR3651STRPBF, IR3651 Datasheet

IR3651SPbF

10/11/2006

HIGH VOLTAGE SYNCHRONOUS PWM BUCK CONTROLLER

Description

The IR3651 is a high voltage PWM controller
designed for high performance synchronous Buck
DC/DC applications. The IR3651 drives a pair of
external N-MOSFETs using a programmable
switching frequency up to 400kHz allows flexibility
to tune the operation of the IC to meet system
level requirements, and synchronization allows
the simplification of system level filter design. The
output voltage can be precisely regulated using
the internal 1.25V reference voltage for low
voltage applications. Protection such as under
voltage lockout and hiccup current limit are
provided to give required system level security in
the event of fault conditions.

Features

• High Voltage Operating up to 75V

• Programmable Switching Frequency up to 400kHz

• 1A Output Drive Capability

• Precision Reference Voltage (1.25V)

• Programmable Soft-Start

• Programmable Over Current Protection

• Hiccup Current Limit Using MOSFET R

DS(on)

sensing

• External Frequency Synchronization

• 14-pin SOIC Package

Applications

• 48V non-isolated DC to DC Converter

• Embedded Telecom Systems

• Networking and Computing Voltage Regulator

• Distributed Point of Load Power Architectures

• General high voltage DC/DC Converters

Typical application Circuit

ORDERING INFORMATION

PKG PACKAGE PIN PARTS PARTS T&R
DESIG DESCRIPTION COUNT PER TUBE PER REEL ORIANTAION
S IR3651SPBF 14 55 ------­S IR3651STRPBF 14 -------- 2500

Fig A

R

OCset

IR3651S

Vcc

Vb

HDrv

LDrv

Fb

Gnd

Comp

SS/SD

C2

C3

C7

R4

Q1

Q2

L1

Vout

C8

V

aux

=12V

PGnd

SYNC

Vin: 12V-75V

DRVcc

C1

R1

R2

Vs

C4

C6

Rt

R5

C5

C10

C9

R3

OCset

Data Sheet No.PD94720

IR3651SPbF

10/11/2006

ABSOLUTE MAXIMUM RATINGS

(Voltages referenced to GND)

• Vcc, DRVcc Supply Voltage ..................................… -0.3V to 20V

• Vs Supply Voltage …………………………………….. -0.3V to 150V

• Vb Supply Voltage …………………………………….. -0.3V to Vs+20V

• OCset …………….…………………………………….. 10mA

• Storage Temperature Range ..................................... -65°C To 150°C

• Operating Junction Temperature Range ................... -40°C To 150°C

• ESD Classification …………………………………..… JEDEC, JESD22-A114 (1K)

• Moisture Sensitivity Level ……………………………. JEDEC Level 3 @ 260

o

C

CAUTION:

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to
the device. These are stress ratings only and functional operation of the device at these or any other conditions
beyond those indicated in the operational sections of the specifications are not implied.

Package Information

14-Pin SOIC NB (S)

2

Θ

JA

= 88.2o C/W

ΘJC= 37o C/W

SYNC

Fb

Vcc

Ldrv

DRVcc

OCset

HDrv

Vs

7

6

5

4

8

9

10

11

3

2

1

12

Rt

13

14

Gnd

PGnd

SS/SD

Comp

Vb

IR3651SPbF

10/11/2006

Block Diagram

Fig. 1: Simplified block diagram of the IR3651

3

64uA Max

POR

Oscillator

Error Amp

Ct

Error Com p

Reset Dom

Vcc

Gnd

4.17V

0.25V

Bias

Generator

3V

1.25V

POR

SS/SD

Fb

Comp

25K

25K

3V

R

S

Q

SYNC

Vb

Rt

4

3

1

2

8

11

13

Vcc

DELAY

UV
DETECT

UV Q
S
R

UV
DETECT

HIGH
VOLTAGE
LEVEL
SHIFT
CIRCUIT

LOW
VOLTAGE
LEVEL
SHIFT

LOW
VOLTAGE
LEVEL
SHIFT

HDrv9

Vs

10

DRVcc7

LDrv6

PGND

5

Vcc

1.25V

14

Rt

10uA

OCset

12

OCP

3uA

OCP

20uA

0.3V

SS

Q

R

S

POR

PBias

IR3651SPbF

10/11/2006

Pin Description

Pin Name Description

1 Fb Inverting input to the error amplifier. This pin is connected directly to the

output of the regulator via resistor divider to set the output voltage and
provide feedback to the error amplifier.

2 Comp Output of error amplifier. An external resistor and capacitor network is

typically connected from this pin to ground to provide loop compensation.

3 SS/SD Soft start / shutdown. This pin provides user programmable soft-start

function. Connect an external capacitor from this pin to ground to set the
start up time of the output voltage. The converter can be shutdown by
pulling this pin below 0.3V.

4 SYNC The internal oscillator can be synchronized to an external clock via this

pin.

5 PGnd Power Ground. This pin serves as a separate ground for the MOSFET

driver and should be connected to the system’s power ground plane.

6 LDrv Output driver for low side MOSFET.

7 DRVcc This pin provides biasing for the internal low side driver. A minimum of

0.1uF, high frequency capacitor must be connected from this pin to power
ground.

8 Vb This pin powers the high side driver and must be connected to a voltage

higher than bus voltage. A minimum of 0.1uF, high frequency capacitor
must be connected from this pin to switch node.

9 HDrv Output driver for high side MOSFET

10 Vs Switch node. Connect this pin to the source of the upper MOSFET and

the drain of the lower MOSFET. This pin is return path for the upper gate
driver.

11 Vcc This pin provides power for the internal blocks of the IC. A minimum of

0.1uF, high frequency capacitor must be connected from this pin to
ground.

12 OCSet Current limit set point. A resistor from this pin to drain of low side

MOSFET will set the current limit threshold.
13 Gnd Signal ground for internal reference and control circuitry.
14 Rt Connecting a resistor from this pin to ground sets the oscillator frequency.

4

IR3651SPbF

10/11/2006

Recommended Operating Conditions

Parameter SYM Test Condition Min TYP MAX Unit

s

Reference Voltage

Feedback Voltage VFB 1.25 V

0oC<Tj<125oC -1.5 +1.5 % Accuracy

-40

o

C<Tj<125oC,

Note1

-3 +1.5 %

Fb Voltage Line Regulation LREG 5V<Vcc<12V 2.0 mV

Supply Current

VCC Supply Current (Stat)

I

CC(Static)

SS=0V, No Switching 6 7 mA

VCC Supply Current (Dyn) I

CC(Dynamic)

Fs=200kHz, C

LOAD

=1.5nF 6 7 mA

DRVcc Supply Current (Stat) I

C(Static)

SS=0V, No Switching 0.3 0.5 mA

DRVcc Supply Current (Dyn) I

C(Dynamic)

Fs=200kHz, C

LOAD

=1.5nF 4 5 mA

Vb Supply Current (Stat) I

b(Static)

SS=0V, No Switching 0.3 0.5 mA

Vb Supply Current (Dyn) I

b(Dynamic)

F

s

=200kHz, C

LOAD

=1.5nF 4.5 5.5 mA

Under Voltage Lockout

VCC-Start-Threshold

VCC_UVLO(R)

Supply ramping up 4.0 4.17 4.35 V

VCC-Stop-Threshold

VCC_UVLO(F)

Supply ramping down 3.75 4.1 V

VCC-Hysteresis

Supply ramping up and down 0.15 0.25 0.3 V

DRVcc-Start-Threshold

DRcc_UVLO(R)

Supply ramping up 8.3 9 9.7 V

DRVcc-Stop-Threshold

DRVcc_UVLO(F)

Supply ramping down 7.5 8.2 8.9 V

DRVCc-Hysteresis

Supply ramping up and down 0.6 0.9 V

Vb-Start-Threshold

Vb_UVLO(R)

Supply ramping up 8.3 9 9.7 V

Vb-Stop-Threshold

Vb_UVLO(F)

Supply ramping down 7.5 8.2 8.9 V

Vb-Hysteresis Supply ramping up and down 0.6 0.9 V

Oscillator

Frequency FS Rt=120K

Rt=51K

170
340

200
400

230
460

kHz

Ramp Amplitude V

ramp

Note2

1.25 V

Min Duty Cycle D

min

Fb=2V 0 %

Min Pulse Width D

min(ctrl)

F

s

=200kHz, Note2

200 ns

Max Duty Cycle D

max

F

s

=200kHz, Fb=1.2V

F

s

=400kHz, Fb=1.2V

80
70

%

Sync Frequency Range Sync(Fs) 20% above free running freq 480 kHz
Sync Pulse Duratin Sync(puls) 200 ns
Sync high Level T hr es hold Sync(H) 2 V
Sync Low Level T hreshold S ync(L) 0.8 V

Electrical Specifications

Unless otherwise specified, these specifications apply over Vcc=5V; DRVcc=Vb=12V, 0oC<Tj< 125oC

5

Symbol Definition Min Max Units

V

bus

Converting Voltage 12 75 V
Vcc Supply Voltage 4.5 13.2 V
DRVcc Supply Voltage 10 16 V
Vb to Vs Supply Voltage 10 16 V
Fs Operating Frequency 100 400 kHz
Tj Junction Temperature -40 125 oC

IR3651SPbF

10/11/2006

Parameter SYM Test Condition Min TYP MAX Units
Error Amplifier

Input Bias Current IFB SS=3V, Fb=1V -0.1 -0.4

µA

Source/Sink Current I(source/Sink) 50 85 120

µA

Transconductance gm 1500 2400 3000

µmho

Soft Start/SD

Soft Start Current ISS SS=0V 15 20 25

µA

Shutdown Output
Threshold

SD 0.25 V

Over Current Protection

OCSET Current I

OCSET

7.5 10 12.5

µA

Hiccup Current I

Hiccup

Note2

3

µA

Hiccup Duty Cycle Hiccup(duty)

I

Hiccup

/ I

SS

, Note2

5 %

Output Drivers

LO, Drive Rise Time Tr(Lo) CL=1.5nF

See Fig 2, Note2

10 20 ns

HI Drive Rise Time Tr(Hi) CL=1.5nF,

See Fig 2, Note2

10 20 ns

LO Drive Fall Time Tf(Lo) CL=1.5nF

See Fig 2,Note2

10 20 ns

HI Drive Fall Time Tf(Hi) CL=1.5nF,

See Fig 2,Note2

10 20 ns

Dead Band Time Tdead See Fig 2 30 45 100 ns
Upper Driver Source

Current

I

upper(source)

HDrv short circuit pulsed

current. PW<10us

1.0 A

Upper Driver Sink
Curret

I

upper(sink)

HDrv short circuit pulsed

current. PW<10us

1.0 A

Lower Driver Source
Current

I

lower(source)

LDrv short circuit pulsed

current. PW<10us

1.0 A

Lower Driver Sink
Current

I

lower(sink)

LDrv short circuit pulsed

current. PW<10us

1.0 A

9V

2V

9V

2V

High Side Driver

(HDrv)

Low Side Driver

(LDrv)

Tr

Tf

Deadband

H_to_L

Deadband
L_to_H

Tr

Tf

Fig. 2: Definition of Rise/Fall time and Deadband Time

6

Note1: Cold temperature performance is guaranteed via correlation using statistical quality control. Not tested in production.
Note2: Guaranteed by Design but not tested in production.