RICHTEK RT9808-15CB, RT9808-15CV, RT9808-15CX, RT9808-42CB, RT9808-42CV Datasheet

Preliminary

RT9808

Micro-Power Voltage Detectors

General Description

The RT9808 is a micro-power voltage detector

supervising the power supply voltage level for

microprocessors (µP) or digital systems. It provides

internally fixed threshold levels with 0.1V per step

ranging from 1.5V to 5V, which covers most digital

applications. It features low supply current of 3µA.

The RT9808 performs supervisory function by

sending out a reset signal whenever the VDD voltage

falls below a preset threshold level. This reset signal

will last the whole period before VDD recovering.

Once VDD recovered up-crossing the threshold level,

the reset signal will be released if VDD is above

threshold and last for the whole period of reset active

time out.

RT9808 is n-channel, open-drain output.

Applications

Computers

z

Controllers

z

Intelligent Instruments

z

Critical µP and µC Power Monitoring

z

Portable/Battery-Powered Equipment

z

Ordering Information

RT9808-

  

Package Type
V : SOT-23
X : SOT-89
B : SOT-25

Features

z

Internally Fixed Threshold 1.5V to 5V in 0.1V Step

z ±

±2% Accuracy

±±

Low Supply Current 3µµµµA

z

Quick Reset within 20µµµµS

z

Built-in Recovery Delay 200mS

z

Low Functional Supply Voltage 0.9V

z

N-Channel Open Drain Output

z

Small 3-Pin SOT-23/SOT89 and 5-Pin SOT-25

z

Packages

Pin Configurations

Part Number Pin Configurations

RT9808-CV

(Plastic SOT-23)

RT9808-CX

(Plastic SOT-89)

RT9808-CB

(Plastic SOT-25)

3

2

1

123

54

3

21

TOP VIEW

1. RESET

2. GND

3. VDD

TOP VIEW

1. RESET

2. VDD

3. GND

TOP VIEW

1. RESET

2. VDD

3. GND

4. NC

5. NC

Typical Application Circuit

Operating temperature range
C: Commercial standard

Reset Threshold

15 : 1.5V

VDD

P

µ

Pull
Up

100K

RT9808

GND

VDD

16 : 1.6V

:

RESET

RESET

49 : 4.9V

50 : 5.0V

DS9808-01 January 2002 www.richtek-ic.com.tw

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RT9808

Pin Description

Pin Name Pin Function

GND Ground Pin

RESET Reset Pulse Output, Negative Pulse

VDD Power Pin

NC No Connected

Function Block Diagram

VDD

Preliminary

VSET

Threshold Voltage Setting

Power On Reset

CMP

POR

TIMER

RESET

N

www.richtek-ic.com.tw DS9808-01 January 2002

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Preliminary

RT9808

Absolute Maximum Ratings

z Terminal Voltage (with Respect to GND)

VDD -0.3V to 6.0V

All Other Inputs -0.3V to VDD+0.3V

z Input Current, VDD 20mA

z Output Current, RESET 20mA

z Power Dissipation, P

SOT-23 0.25W

SOT-89 0.5W

SOT-25 0.25W

z Operating Junction Temperature Range -40°C ~ 125°C

z Storage Temperature Range -65°C ~ 125°C

z Package Thermal Resistance

SOT-23, θ

SOT-89, θ

SOT-89, θ

SOT-25, θ

z Lead Temperature (Soldering, 5sec.) 260°C

JA

JC

JA

JA

@ TA = 25°C

D

250°C /W

100°C /W

300°C /W

250°C /W

Electrical Characteristics

(VDD = 3.0, unless specified)

Parameter Symbol Test Conditions Min Typ Max Units

Operating VDD (V

Supply Current

Reset Threshold

Threshold Voltage Accuracy

VCC Drop to Reset Delay t

Reset Active Time Out Period

RESET Output Voltage

Note1: 1.5V ~ 5V, step 0.1V

) Range V

OUT

I

DD

V

∆V

RD

t

RP

V

DD

TH

OL

0.9 -- 6 V

VDD = 1.5V ~ 5V, I

TA = 27°C

TA = 27°C

TH

OUT

= 0

-- 3 --

-- Note1 -- V

-- -- 2 %

Drop = -125mV -- -- 20

VDD ≥ 1.02×V

V

< VTH, I

DD

TH

SINK

> 3.5mA

-- 200 -- mS

-- 0.4 -- V

µA

µS

DS9808-01 January 2002 www.richtek-ic.com.tw

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RT9808

Measuring Circuit

Preliminary

(1) Detection Voltage

V

DD

V

RT9808

(2) Current Consumption

A

V

DD

V

V

DD

V

SS

V

RT9808

DD

R (100kΩ)

OUT

OUT

Oscilloscope

(3) Output Transistor Current

V

DD

RT9808

OUT

P.G

V

SS

(4) Dynamic Response

V

DD

V

DD

V

RT9808

100k

CRT

CL

OUT

Ω

6V

A

SS

V

V

DS

V

SS

V

www.richtek-ic.com.tw DS9808-01 January 2002

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