SI-8511NVS [SANKEN]

Surface-Mount Synchronous Rectifier Step-down Switching Mode Regulator Control ICs; 表面贴装同步整流降压开关模式稳压器控制IC


型号：	SI-8511NVS
厂家：	SANKEN ELECTRIC
描述：	Surface-Mount Synchronous Rectifier Step-down Switching Mode Regulator Control ICs 表面贴装同步整流降压开关模式稳压器控制IC 稳压器开关式稳压器或控制器电源电路开关式控制器光电二极管
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1-1-2 Switching Mode Regulator ICs

SI-8511NVS Surface-Mount, Synchronous Rectifier Step-down Switching Mode Regulator Control ICs

■Features

■Absolute Maximum Ratings

(Ta=25°C)

• Surface-mount package (TSSOP24)

Parameter

Control-System DC Input Voltage

DC Input Voltage

Symbol

Ratings

Unit

VCC

• High efficiency due to synchronous rectifica-

tion: 92% (at V^IN= 5V, IO = 1A, VO = 2.5V)

VIN

Boost Block Input Voltage

EN Terminal Input Voltage

PWRGD Terminal Applied Voltage

Junction Temperature

VCC

• Capable of downsize a choke-coil due to IC's

high switching frequency (400kHz typ, On

Time Control). (Compared with conventional

Sanken devices)

VEN

VPWRGD

+150

°C

Storage Temperature

Tstg

–40 to +150

• Low reference voltage (V^ref) of 1.1V. The

output voltage is variable from 1.1V to 6V.

• High-speed response to a load

• Compatible with low ESR capacitors

• Soft start and output ON/OFF available

• Built-in overcurrent and output-overvoltage

protection circuits

• PWRGD function to indicate the output voltage

status

• High precision reference voltage: 1.1V 1.2%

■Applications

• Power supplies for notebook PCs and mobile devices

• Onboard local power supplies

• OA equipment

• For stabilization of the secondary-side output voltage of switching power supplies

■Recommended Operating Conditions

Parameter

Control System Input Voltage Range

Input Voltage Range

Symbol

VCC

VIN

Ratings

Unit

4.5 to 5.5

3 to 18

Output Voltage Range

1.1 to 6

Operating Temperature Range

Top

–20 to +85

°C

■Electrical Characteristics

(Ta=25°C unless otherwise specified)

Ratings

typ.

Parameter

Symbol

Unit

Conditions

min.

max.

Dynamic

Output Voltage

∆VO/∆T

Iop

–1.2%

1.1

+1.2%

mV/°C

µA

VIN=5V, VCC=5V, VSNS connected to VO, IO=0A

IN=5V, VCC=5V, VSNS connected to VO, I =0A, T =0 to 85°C

Characteristics

Temperature Coefficient of Output Voltage

Circuit Current (VCC Terminal)

Circuit Current (VIN Terminal)

Standby Current 1 (VCC Terminal)

Standby Current 2 (VIN Terminal)

0.03

VCC=5V, EN=H, FADJ:open

VIN=5V, EN=H

VCC=5V, EN=L

VIN=5V, EN=L

VIN=5V

Circuit

Iop

Current

Istd1

100

Istd2

Undervoltage UVLO Operating Voltage 1 (VCC Terminal)

Vuvlo1

Vuvlo2

Ton

3.7

2.5

4.45

2.9

Lockout

UVLO Operating Voltage 2 (VIN Terminal)

On Time

VCC=5V

1.27

0.7

µS

VCC=5V, VIN=5V, VO=2.5V

VCC=5V

On Time

Control

Minimum Off Time

Toff

REF Terminal Voltage

Vref

1.1

1.2

1.3

VCC=5V

REF Terminal Source Current

On Resistance (high side)

On Resistance (low side)

On Resistance (high side)

On Resistance (low side)

Bootstrap Voltage

Iref

100

µA

Ω

VCC=5V

High Side

Drive

RonHH

RonHL

RonLH

RonLL

VH-VLIN

Ilim

5.5

VH-VLIN=5V

VCC=5V

Ω

Low Side

Drive

Ω

VCC=5V

Bootstrap

4.5

5.5

Current for Current Limit Detection

Soft Start Terminal Current

EN Low Level Voltage

100

110

µA

VCC=5V, VIN=5V

VCC=5V

Iss

Vcelo

Vcehi

ICE

0.8

VCC

VCC=5V

EN High Level Voltage

2.4

VCC=5V

Protection

System

EN Bias Level Current

µA

VCC=5V, EN=5V

VCC=5V

PWRGD Good Voltage (high side)

PWRGD Good Voltage (low side)

PWRGD Low Output Voltage

PWRGD Terminal Current

PWRGD Leakage Current

Vsens

Vpwrgd

Ipwrgd

1.32

0.88

VCC=5V

0.4

120

VCC=5V, Ipwrgd=120µA

VCC=5V, Vpwrgd=0.4V

Vpwrgd=5V

µA

ICs

SI-8511NVS

■External Dimensions (TSSOP24)

(Unit : mm)

2.0

Mirror surface

Depth 0.02 to 0.08

1.0

Mirror surface

Depth 0.02 to 0.08

3.00

0.65

0.375 TYP

+0.1

0.22

–0.05

0.12

7.80 0.1

7.9 0.2

0.4

Plastic Mold Package Type

Flammability: UL94V-0

Product Mass: Approx. 1.36g

0.50 0.2

0.08

■Block Diagram (Pin Assignment)

+5V

VCC1

ILIM

IN ISEN

VCC2

OCP

PRE_REG

Vpreg

Level

Shift

Latch

Buff

H : ON

: OFF

UVLO

Gate Driver

OFF Clamp

DRVH

LIN

Synchronous

Cont.

(Logic)

Logic

Buff

POWER_GOOD

H : GOOD

Power

Good

DRVL

PGND

PWRGD

: NG

–

Switching

Constant On

Time Cont.

VSNS

COMP

–

OSC

GND

OVP_SL

FADJ

FSET

SKIP

Open : Change Frequency

Short : 400KHz Operation

Open : Skip Mode

: No Skip Mode

■Typical Connection Diagram

MOS FET Q¹, Q2

• Be sure to use logic type MOS FET as Q1 and Q2.

C1 : 10

CC : 5V

If you use a normal power MOS FET type, the ON resistance may not drop to a

satisfactory level due to a shortage of V^GS. This may deteriorate the efficiency

and cause overheating.

C7 : 0.1 F

D2 : SFPL52

5mΩ

10Ω

Diode D¹

• Be sure to use a Schottky-barrier diode for D1.

If other diodes like fast recovery diodes are used, IC may be destroyed because

of the reverse voltage generated by the recovery voltage or ON voltage.

LIN

L1 : 10

DRVH

C2 :

DRVL

PGND

330

10Ω

Choke coil L¹

SJPJ-L3

VIN

• If the winding resistance of the choke coil is too high, the efficiency may drop

below the rated value.

• Take care concerning heat radiation from the choke coil caused by magnetic

saturation due to overload or short-circuit load.

1000

0.1 ~ 1

R13

C5 : 4.7

ISEN

ILIN

VCC2

OVP_SL

R12

SI-8511NVS

C4 : 3.3

C8 : 220pF

GND

VSNS

VCC1

VCC

Capacitor C1, C2

47kΩ

• As large ripple currents flow through C1 and C2, use high-frequency and low-

impedance capacitors suitable for switching mode power supplies. Especially

when the impedance of C²is high, the switching waveform may become abnor-

mal at low temperatures. For C², do not use a capacitor with an extremely low

equivalent series resistance (ESR) such as a ceramic capacitor, which may cause

an abnormal oscillation.

47kΩ

R10

2.2kΩ

0.1

SKIP

PWRGD

REF

SKIP

FADJ

PWRGD

R11 : 100kΩ

* To create the optimum operating conditions, place the components as close as

possible to each other.

R8 : 200kΩ

ICs

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