L4989MD [STMICROELECTRONICS]

低功耗稳压器;


型号：	L4989MD
厂家：	ST
描述：	低功耗稳压器信息通信管理光电二极管输出元件电源电路线性稳压器IC 调节器
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L4989

LOW POWER VOLTAGE REGULATOR

PRODUCT PREVIEW

■ OPERATING DC SUPPLY VOLTAGE RANGE

5.6V TO 31V

■ VERY LOW QUIESCENT CURRENT WITH

WATCHDOG DISABLED

■ PRECISION OUTPUT VOLTAGE (3%)

■ LOW-DROP VOLTAGE

(180mV typ at I = 150mA)

SO8

SO20

■ RESET CIRCUIT SENSING THE OUTPUT

VOLTAGE DOWN TO 1V

ORDERING NUMBERS: L4989D (SO8)

■ PROGRAMMABLE RESET DELAY WITH

L4989 (SO20)

EXTERNAL CAPACITOR

■ WATCHDOG DISABLE INPUT

■ PROGRAMMABLE WATCHDOG TIMER WITH

EXTERNAL CAPACITOR

■ THERMAL SHUTDOWN AND SHORT

CIRCUIT PROTECTION

■ WIDE TEMPERATURE RANGE (T = -40°C TO

150°C)

BLOCK DIAGRAMt

Start up

1.25V

Voltage

Reference

gnd

100mV

Vcw

watchdog

Res

Ctw

Vcr

Ctr

Reset

March 2004

1/10

This is preliminary information on a new product now in development. Details are subject to change without notice.

L4989

PIN DESCRIPTION

N. (SO8)

N. (SO20)

NAME

FUNCTION

WEn

Watchdog enable input.

If high it activates the watchdog operation.

gnd

Ground reference

5,6,15,16

Ground

Connected these pins to a heat spreader ground

Res

Vcr

Vcw

Reset output.

It is pulled down when output voltage goes below Vo_th or

frequency at Wi is too low.

Reset timing adjust.

A capacitor between Vcr pin and gnd, sets the reset delay time

(trd)

Watchdog timer adjust

A capacitor between Vcw pin and gnd, sets the time response of

the watchdog monitor.

Watchdog input.

If the frequency at this input pin is too low, the Reset output is

activated.

Voltage regulator output

Block to ground with a capacitor >100nF (needed for regulator

stability)

Supply voltage

Block to ground directly at IC pin with a ceramic capacitor

2,3,8,9,12,

13,18,19

N. C.

not connected

PIN CONNECTIONS

VEN

N.C.

GND

RES

N.C.

VCR

N.C.

VEN

GND

RES

VCR

V_S

GND

VCW

D04AT515

SO8

N.C.

WCW

D04AT516

SO20

2/10

L4989

ABSOLUTE MAXIMUM RATINGS

Symbol

Parameter

Value

Unit

DC supply voltage

Input current

-0.3 to 40

Vsdc

internally limited

-0.3 to 6

Vsdc

DC output voltage

DC output current

Watchdog input voltage

internally limited

-0.3 to VVo + 0.3

internally limited

-0.3 to VVo + 0.3

-0.3 to 40

Open drain output voltage (RES)

Open drain output current (RES)

Reset delay voltage

Watchdog delay voltage

Watchdog enable input

WEn

Junction temperature

-40 to 150

°C

ESD voltage level (HBM-MIL STD 883C)

ESD

Note:

Maximum ratings are absolute ratings; exceeding any one of these values may cause perma-nent damage to the integrated circuit.

THERMAL DATA

Symbol

Parameter

SO8

SO12+4+4

Unit

Thermal Resistance Junction to ambient

130 to 180

50(*)

°C/W

th-j amb

(*) with 6 sq. cm on board heat sink

ELECTRICAL CHARACTERISTICS (Vs = 5.6V to 31V, Tj = -40°C to +150°C unless otherwise specified)

Symbol

Parameter

Test Condition

Min.

Typ.

Max.

Unit

GENERAL

o_ref

Output voltage

Vs=5.6 to 31V

4.85

5.00

5.15

Io=1 to 150mA

Short circuit current (1)

Output current limitation (1)

Line regulation voltage

Vs=13.5V

160

170

210

250

290

short_13

lim

Vs=13.5V

Vs, Vo

line

Vs=5.6 to 31V

Io=1 to 150mA

Load regulation voltage

Drop voltage

Io=1 to 150mA

Io=150mA

load

Vs, Vo

180

400

SVR

Ripple rejection

fr = 100 Hz

Current consumption

with watchdog not active

Vs=13.5V, Io<1mA,

WEn low

115

µA

qs_1

= I – I

Vs o

qs_1

3/10

L4989

Symbol

Parameter

Test Condition

Vs=13.5V,

Io=10mA,

WEn low

Min.

Typ.

Max.

Unit

Vs, Vo

Current consumption

with watchdog not active

127

300

µA

qs_10

= I – I

qs_10

Vs o

Vs, Vo

Current consumption

with watchdog not active

Vs=13.5V, Io=50mA,

WEn low

498

1.40

110

900

µA

qs_50

= I – I

qs_50

Vs o

Current consumption

with watchdog not active

Vs=13.5V, Io=150mA,

WEn low

qs_150

= I – I

qs_150

Vs o

Current consumption

with watchdog active

Vs=13.5V, Io<1mA,

WEn high

170

350

1000

2.00

190

qn_1

= I – I

qn_1

Vs o

Current consumption

with watchdog active

Vs=13.5V,

Io=10mA,

WEn high

168

538

1.45

qn_10

qn_50

= I – I

Vs o

qn_10

Current consumption

with watchdog active

Vs=13.5V,

Io=50mA,

WEn high

= I – I

Vs o

qn_50

Current consumption

with watchdog active

Vs=13.5V,

Io=150mA,

WEn high

qn_150

= I – I

Vs o

qn_150

Thermal protection temperature

150

°C

Tw_hy Thermal protection temperature

hysteresis

Note: 1. see fig1 (behavior of output current versus regulated voltage Vo)

RESET

Symbol

Parameter

Test condition

min

typ

max

Unit

Res

Vres_l

Reset output low voltage

Rext = 5kΩ to Vo,

Vo > 1V

0.4

Res

Reset output high leakage

current

= 5V

µA

kΩ

Res_lkg

Res

Internal Pull up resistance

Reset threshold voltage

versus Vo

Res

Vo_th

Vs = 5.6 to 31V Io = 1 to

150mA

10% below

o_ref

Vcr

Res

Vrhth

Vrlth

Icr

Reset timing low threshold

Reset timing high threshold

Charge current

Vs =13.5V

10%

44%

13%

47%

16%

50%

µA

µs

Idr

Discharge current

trr_2

trd

Reset reaction time (2)

Reset delay time

Vo = V

- 100mV

100

250

115

700

165

o_th

Vs =13.5V, Ctr =1nF

2. When Vo becomes lower than 4V, the reset reaction time decreases down to 2 s assuring a faster reset condition in this particular

case.

4/10

L4989

WATCHDOG

Symbol

Vih

Parameter

Input high voltage

Test condition

Vs=13.5V

min

typ

max

Unit

3.5

Vil

Input low voltage

Input hysteresis

Pull down resistor

Low threshold

Vs=13.5V

1.5

Vih

Vs=13.5V

500

100

13%

47%

kΩ

Rwi

Vs=13.5V

10%

44%

250

16%

50%

Vcw

Res

Vwhth

Vwlth

Icwc

Icwd

Twop

twol

Vs=13.5V

o_ref

High threshold

Vs=13.5V

o_ref

Charge current

Vs=13.5V, Vcw=0.1V

Vs=13.5V, Vcw=2.5V

Vs=13.5V, Ctw=47nF

µA

Discharge current

Watchdog period

Watchdog output low time

1.25

2.5

WEn

Symbol

Parameter

WEn input low voltage

WEn input high voltage

WEn input hysteresis

Pull down current

Test condition

min

typ

max

Unit

WEn

WEn_low

WEn_high

WEn_hyst

600

920

2.5

1300

µA

WEn

Vs=13.5V

VOLTAGE REGULATOR

The voltage regulator uses a p-channel MOS transistor as a regulating element. With this structure a very

low dropout voltage at current up to 150mA is obtained. The output voltage is regulated up to transient

input supply voltage of 40V. No functional interruption due to over-voltage pulses is generated.

The voltage Regulator is always active and not depending on the state of WEn input pin.

A short circuit protection to GND is provided.

Figure 1. Behavior of output current versus regulated voltage Vo

Vo_ref

Ishort Ilim

Iout

5/10

L4989

The reset circuit monitors the output voltage Vo. If the output voltage stays lower than Vo_th for filter time

trr, then Res goes low. If the output voltage Vo becomes lower than 2.0V (typ) than Res goes immediately

low. The reset low signal is guaranteed for an output voltage Vo greater than 1V.

When the output voltage goes back higher than Vo_th then Res goes high with a delay trd. This delay is

obtained by 512 period of an oscillator. The oscillator period is given by:

(V_rhth– V_rlth) ⋅ Ctr (V_rhth– V_rlth) ⋅ Ctr

T_osc= ------------------------------------------------- + -------------------------------------------------

Icr

trd is given by

where:

trd = 512 x Tosc

Icr = 15µA is an internally generated charge current,

Idr = 15µA is an internally generated discharge current,

Vrhth=2.35V and Vrlth=0.65V are two typ thresholds,

Ctr is an external capacitance.

The Reset is always active and not depending on the state of WEn input pin.

Figure 2. Reset Time Diagram

Vout_th

< trr

Tosc

Vrhth

Vrlth

trr

Vcr

trd = 512 Tosc

Res

Watchdog

The watchdog input Wi monitors a connected microcontroller. If pulses are missing, the Reset output

Res is set to low. The pulse sequence time can be set within a wide range with the external capacitor Ctw.

The watchdog circuit discharges the capacitor Ctw with the con-stant current Icwd. If the lower threshold

Vwlth is reached, a watchdog reset is generated.

To prevent this reset the microcontroller must generate a positive edge during the discharge of the capac-

itor before the voltage has reached the threshold Vwlth. In order to calculate the minimum time t during

dis

which the microcontroller must output the positive edge the fol-lowing equation can be used

(Vwhth-Vwlth) x Ctw = Icwd x t

dis

Every Wi positive edge switches the current source from discharging to charging, the same happens when

the lower threshold is reached. When the voltage reaches the upper threshold Vwhth the current switches

from charging to discharging. The result is a saw toothwaveform at the watchdog timer capacitor Ctw.

The Watchdog operation is active only if WEn input pin is set to logic state high.

6/10

L4989

Figure 3. Watchdog time diagram

Twop

Vwhth

Vwlth

Vcw

Res

twol

7/10

L4989

inch

DIM.

OUTLINE AND

MECHANICAL DATA

MIN. TYP. MAX. MIN.

TYP. MAX.

0.069

1.35

0.10

1.10

0.33

0.19

4.80

1.75 0.053

0.25 0.004

1.65 0.043

0.51 0.013

0.25 0.007

5.00 0.189

0.010

0.065

0.020

0.010

(1)

0.197

3.80

4.00

0.15

0.157

0.050

1.27

5.80

0.25

0.40

6.20 0.228

0.50 0.010

1.27 0.016

0˚ (min.), 8˚ (max.)

0.10

0.244

0.020

0.050

ddd

0.004

Note: (1) Dimensions D does not include mold flash, protru-

sions or gate burrs.

SO-8

Mold flash, potrusions or gate burrs shall not exceed

0.15mm (.006inch) in total (both side).

0016023 C

8/10

L4989

inch

DIM.

OUTLINE AND

MECHANICAL DATA

MIN. TYP. MAX. MIN.

TYP. MAX.

0.104

2.35

0.10

0.33

0.23

12.60

2.65 0.093

0.30 0.004

0.51 0.013

0.32 0.009

13.00 0.496

0.012

0.200

0.013

(1)

0.512

7.40

7.60 0.291

0.299

0.050

1.27

10.0

0.25

0.40

10.65 0.394

0.75 0.010

1.27 0.016

0˚ (min.), 8˚ (max.)

0.10

0.419

0.030

0.050

ddd

0.004

SO20

(1) “D” dimension does not include mold flash, protusions or gate

burrs. Mold flash, protusions or gate burrs shall not exceed

0.15mm per side.

0016022 D

9/10

L4989

Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences

of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted

by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject

to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not

authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.

The ST logo is a registered trademark of STMicroelectronics.

All other names are the property of their respective owners

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10/10

L4989MD [STMICROELECTRONICS]

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