HEF4541BF [NXP]

Programmable timer; 可编程定时器


型号：	HEF4541BF
厂家：	NXP
描述：	Programmable timer 可编程定时器
文件：	总9页 (文件大小：147K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

INTEGRATED CIRCUITS

DATA SHEET

For a complete data sheet, please also download:

• The IC04 LOCMOS HE4000B Logic

Family Specifications HEF, HEC

• The IC04 LOCMOS HE4000B Logic

Package Outlines/Information HEF, HEC

HEF4541B

MSI

Programmable timer

January 1995

Product speciﬁcation

File under Integrated Circuits, IC04

Philips Semiconductors

Product speciﬁcation

HEF4541B

MSI

Programmable timer

disables the oscillator to provide no active power

DESCRIPTION

dissipation.

The HEF4541B is a programmable timer which consists of

a 16-stage binary counter, an integrated oscillator to be

used with external timing components, an automatic

power-on reset and output control logic. The frequency of

the oscillator is determined by the external components

R_tand C_twithin the frequency range 1 Hz to 100 kHz. This

oscillator may be replaced by an external clock signal at

input RS, the timer advances on the positive-going

transition of RS. A LOW on the auto reset input (AR) and

a LOW on the master reset input (MR) enables the internal

power-on reset. A HIGH level at input MR resets the

counter independent on all other inputs. Resetting

A HIGH at input AR turns off the power-on reset to provide

a low quiescent power dissipation of the timer. The

16-stage counter divides the oscillator frequency by

2⁸, 2¹⁰, 2¹³or 2¹⁶depending on the state of the address

inputs (A₀, A₁). The divided oscillator frequency is

available at output O. The phase input (PH) features a

complementary output signal. If the mode select input

(MODE) is LOW or HIGH the timer can be used

respectively as a single transition timer or 2ⁿfrequency

divider.

Fig.1 Functional diagram.

HEF4541BP(N): 14-lead DIL; plastic

(SOT27-1)

HEF4541BD(F):

14-lead DIL; ceramic (cerdip)

(SOT73)

HEF4541BT(D):

14-lead SO; plastic

(SOT108-1)

( ): Package Designator North America

FAMILY DATA, I_DDLIMITS category MSI

Fig.2 Pinning diagram.

See Family Specifications

January 1995

Philips Semiconductors

Product speciﬁcation

HEF4541B

MSI

Programmable timer

Fig.3 Logic diagram.

January 1995

Philips Semiconductors

Product speciﬁcation

HEF4541B

MSI

Programmable timer

PINNING

FUNCTION TABLE

A₀, A₁

MODE

address inputs

INPUTS

MODE

mode select input

AR MR PH

MODE

auto reset input

auto reset disabled

auto reset enabled ⁽¹⁾

master reset active

normal operation selected

division to output

single-cycle mode ⁽²⁾

output initially LOW,

after reset

master reset input

phase input

R_TC

C_TC

external resistor connection (R_t)

external capacitor connection (C_t)

external resistor connection (R_S) or

external clock input

FREQUENCY SELECTION TABLE

NUMBER OF

output initially HIGH,

after reset

f_osc

-------

- = 2 ⁿ

f_out

A₀

A₁

COUNTER STAGES n

Notes

1. For correct power-on reset, the supply voltage should

be above 8.5 V. For V_DD< 8.5 V, disable the autoreset

8 192

1 024

256

and connect AR to V_DD

2. The timer is initialized on a reset pulse and the output

changes state after 2^n-1counts and remains in that

state (latched). Reset of this latch is obtained by

master reset or by a LOW to HIGH transition on the

MODE input.

65 536

H = HIGH state (the more positive voltage)

L = LOW state (the less positive voltage)

X = state is immaterial

RC oscillator

Timing component limitations

The oscillator frequency is mainly determined by

R_tC_t, provided R_t<< R_Sand R_SC2 << R_tC_t. The function of

R_Sis to minimize the influence of the forward voltage

across the input protection diodes on the frequency. The

stray capacitance C2 should be kept as small as possible.

In consideration of accuracy, C_tmust be larger than the

inherent stray capacitance. R_tmust be larger than the

LOCMOS ‘ON’ resistance in series with it, which typically

is 500 Ω at V_DD= 5 V, 300 Ω at V_DD= 10 V and 200 Ω at

V_DD= 15 V.

Typical formula for oscillator

frequency:

The recommended values for these components to

maintain agreement with the typical oscillation formula are:

C_t≥ 100 pF, up to any typical value,

f_osc= ---------------------------------

2, 3 × R_t× C_t

10 kΩ ≤ R_t≤ 1 MΩ.

Fig.4 External component connection for RC

oscillator; R_S≈ 2 R_t.

January 1995

Philips Semiconductors

Product speciﬁcation

HEF4541B

MSI

Programmable timer

C_tcurve at R_t= 56 kΩ; R_S= 120 kΩ.

− − − R_tcurve at C_t= 1 nF; R_S= 2 R_t.

Fig.5 RC oscillator frequency as a function of R_tand C_tat V_DD= 5 to 15 V; T_amb= 25 °C.

January 1995

Philips Semiconductors

Product speciﬁcation

HEF4541B

MSI

Programmable timer

R_t= 56 kΩ; C_t= 1 nF; R_S= 0.

− − − R_t= 56 kΩ; C_t= 1 nF; R_S= 120 kΩ.

Fig.6 Frequency deviation (∆f) as a function of ambient temperature; referenced at : f_oscat T_amb= 25 °C and

V_DD= 10 V.

January 1995

Philips Semiconductors

Product speciﬁcation

HEF4541B

MSI

Programmable timer

DC CHARACTERISTICS

V_SS= 0 V

T_amb(°C)

+ 25

V_DDV_OLV_OH

SYMBOL

−40

+ 85

MIN. MAX. MIN. TYP. MAX. MIN. MAX.

Supply current

−

750

−

80 −

230 µA

700 µA

power-on reset

I_D

250

600 −

enabled (note)

1600

500 1300 −

1500 µA

Supply voltage for automatic

reset initialization (note)

Output current

V_DD

−

8,5

0,4

−

4,6

0,5

0,3

HIGH; C_TC, R_TC

9,5 −I_OH

13,5

1,4

1,2

0,95

3,2

4,8

4,0

2,5 −I_OH

1,4

1,2

0,95

0,20

0,68

2,30

Output current

LOW; C_TC, R_TC

0,4

0,33

1,00

3,20

0,27

0,85

2,70

10 0,5

15 1,5

I_OL

Note

1. All inputs at 0 V or V_DD; except input AR = input MR = 0 V (power-on reset active).

AC CHARACTERISTICS

V_SS= 0 V; T_amb= 25 °C; input transition times ≤ 20 ns

V_DD

TYPICAL FORMULA FOR P (µW)⁽¹⁾

Dynamic power dissipation

per package

1 300 f_i+ f_oC_LV_DD

5 300 f_i+ f_oC_LV_DD

12 000 f_i+ f_oC_LV_DD

(P)

Total power dissipation

when using the

1 300 f_osc

5 300 f_osc

12 000 f_osc

f_oC_LV_DD

+ 2C_tV_DDf_osc

+ 10 V_DD

+ 100 V_DD

+ 400 V_DD

+ 2C_tV_DDf_osc

on-chip oscillator (P)

+ 2C_tV_DDf_osc

Notes

1. where:

f_i

= input frequency (MHz)

f_o= output frequency (MHz)

C_L= load capacitance (pF)

V_DD= supply voltage (V)

C_t= timing capacitance (pF)

f_osc= oscillator frequency (MHz)

January 1995

Philips Semiconductors

Product speciﬁcation

HEF4541B

MSI

Programmable timer

AC CHARACTERISTICS

V_SS= 0 V; T_amb= 25 °C; C_L= 50 pF; input transition times ≤ 20 ns

V_DD

TYPICAL EXTRAPOLATION

FORMULA

SYMBOL MIN. TYP. MAX.

Propagation delays

RS → O

2⁸selected

375

150

110

750 ns

300 ns

220 ns

348 ns

139 ns

102 ns

(0,55 ns/pF) C_L

(0,23 ns/pF) C_L

(0,16 ns/pF) C_L

t_PHL

t_PLH

;

HIGH to LOW

LOW to HIGH

RS → O

2¹⁰selected

425

165

120

850 ns

330 ns

240 ns

398 ns

154 ns

112 ns

(0,55 ns/pF) C_L

(0,23 ns/pF) C_L

(0,16 ns/pF) C_L

t_PHL

t_PLH

HIGH to LOW

LOW to HIGH

RS → O

¹³selected

510 1020 ns

483 ns

179 ns

127 ns

(0,55 ns/pF) C_L

(0,23 ns/pF) C_L

(0,16 ns/pF) C_L

t_PHL

t_PLH

HIGH to LOW

LOW to HIGH

190

135

380 ns

270 ns

RS → O

2¹⁶selected

575 1150 ns

548 ns

199 ns

142 ns

(0,55 ns/pF) C_L

(0,23 ns/pF) C_L

(0,16 ns/pF) C_L

t_PHL

t_PLH

HIGH to LOW

LOW to HIGH

210

150

420 ns

300 ns

Minimum clock

pulse width; LOW

t_WRSL

t_WMRH

f_max

Minimum reset

pulse width; HIGH

Maximum clock

pulse frequency

MHz

kHz

Oscillator frequency

R_t= 5 kΩ

f_osc

C_t= 1 nF

R_S= 10 kΩ

R_t= 56 kΩ

C_t= 1 nF

f_osc

R_S= 120 kΩ

January 1995

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