DATA SH EET
Product specification
File under Integrated Circuits, IC04 January 1995
INTEGRATED CIRCUITS
HEF4541B
MSI
Programmable timer
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
January 1995 2
Philips Semiconductors Product specification
Programmable timer HEF4541B
MSI
DESCRIPTION
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
Rtand Ctwithin 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
disables the oscillator to provide no active power
dissipation.
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
28,2
10,2
13 or 216 depending on the state of the address
inputs (A0,A
1
). 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.
Fig.2 Pinning diagram. FAMILY DATA, IDD LIMITS category MSI
See Family Specifications
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
January 1995 3
Philips Semiconductors Product specification
Programmable timer HEF4541B
MSI
Fig.3 Logic diagram.
January 1995 4
Philips Semiconductors Product specification
Programmable timer HEF4541B
MSI
PINNING
FREQUENCY SELECTION TABLE
A0,A
1address inputs
MODE mode select input
AR auto reset input
MR master reset input
PH phase input
RTC external resistor connection (Rt)
CTC external capacitor connection (Ct)
RS external resistor connection (RS)or
external clock input
A0A1NUMBER OF
COUNTER STAGES n
L L 13 8 192
L H 10 1 024
H L 8 256
H H 16 65 536
fosc
fout
--------- 2n
=
FUNCTION TABLE
Notes
1. For correct power-on reset, the supply voltage should
be above 8.5 V. For VDD < 8.5 V, disable the autoreset
and connect AR to VDD.
2. The timer is initialized on a reset pulse and the output
changes state after 2n-1 counts 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.
H = HIGH state (the more positive voltage)
L = LOW state (the less positive voltage)
X = state is immaterial
INPUTS MODE
AR MR PH MODE
H L X X auto reset disabled
L L X X auto reset enabled (1)
X H X X master reset active
X L X H normal operation selected
division to output
X L X L single-cycle mode (2)
X L L X output initially LOW,
after reset
X L H X output initially HIGH,
after reset
RC oscillator
Fig.4 External component connection for RC
oscillator; RS≈2 Rt.
Typical formula for oscillator
frequency:
fosc 1
23 R
tC
t
××,
---------------------------------=
Timing component limitations
The oscillator frequency is mainly determined by
RtCt, provided Rt << RSand RSC2 << RtCt. The function of
RSis 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, Ctmust be larger than the
inherent stray capacitance. Rtmust be larger than the
LOCMOS ‘ON’ resistance in series with it, which typically
is 500 Ω at VDD = 5 V, 300 Ωat VDD = 10 V and 200 Ωat
VDD = 15 V.
The recommended values for these components to
maintain agreement with the typical oscillation formula are:
Ct≥100 pF, up to any typical value,
10 kΩ≤R
t≤1MΩ.
January 1995 5
Philips Semiconductors Product specification
Programmable timer HEF4541B
MSI
Fig.5 RC oscillator frequency as a function of Rtand Ctat VDD = 5 to 15 V; Tamb =25°C.
Ctcurve at Rt= 56 kΩ;R
S= 120 kΩ.
−−− R
tcurve at Ct= 1 nF; RS=2 R
t
.
January 1995 6
Philips Semiconductors Product specification
Programmable timer HEF4541B
MSI
Fig.6 Frequency deviation (∆f) as a function of ambient temperature; referenced at : fosc at Tamb =25°C and
VDD = 10 V.
Rt= 56 kΩ;C
t= 1 nF; RS=0.
−−−R
t= 56 kΩ; Ct= 1 nF; RS= 120 kΩ.
January 1995 7
Philips Semiconductors Product specification
Programmable timer HEF4541B
MSI
DC CHARACTERISTICS
VSS =0 V
Note
1. All inputs at 0 V or VDD; except input AR = input MR = 0 V (power-on reset active).
AC CHARACTERISTICS
VSS = 0 V; Tamb =25°C; input transition times ≤20 ns
Notes
1. where:
fi= input frequency (MHz)
fo= output frequency (MHz)
CL= load capacitance (pF)
VDD = supply voltage (V)
Ct= timing capacitance (pF)
fosc = oscillator frequency (MHz)
VDD
VVOL
VVOH
VSYMBOL
Tamb (°C)
−40 +25 +85
MIN. MAX. MIN. TYP. MAX. MIN. MAX.
Supply current 5 −80 −20 80 −230 µA
power-on reset 10 ID−750 −250 600 −700 µA
enabled (note) 15 −1600 −500 1300 −1500 µA
Supply voltage for automatic
reset initialization (note) VDD −−8,5 5 −− −V
Output current 5 4,6 0,5 −0,4 −− 0,3 −mA
HIGH; CTC,R
TC 10 9,5 −IOH 1,4 −1,2 −− 0,95 −mA
15 13,5 4,8 −4,0 −− 3,2 −mA
5 2,5 −IOH 1,4 −1,2 −− 0,95 −mA
Output current 5 0,4 0,33 −0,27 −− 0,20 −mA
LOW; CTC,R
TC 10 0,5 IOL 1,00 −0,85 −− 0,68 −mA
15 1,5 3,20 −2,70 −− 2,30 −mA
VDD
VTYPICAL FORMULA FOR P (µW)(1)
Dynamic power dissipation 5 1 300 fi+foCLVDD2
per package 10 5 300 fi+foCLVDD2
(P) 15 12 000 fi+foCLVDD2
Total power dissipation 5 1 300 fosc +foCLVDD2+2CtVDD2fosc +10 VDD
when using the 10 5 300 fosc +foCLVDD2+2CtVDD2fosc +100 VDD
on-chip oscillator (P) 15 12 000 fosc +foCLVDD2+2CtVDD2fosc +400 VDD
January 1995 8
Philips Semiconductors Product specification
Programmable timer HEF4541B
MSI
AC CHARACTERISTICS
VSS = 0 V; Tamb =25°C; CL= 50 pF; input transition times ≤20 ns
VDD
VSYMBOL MIN. TYP. MAX. TYPICAL EXTRAPOLATION
FORMULA
Propagation delays
RS →O
28selected 5 tPHL;
tPLH
375 750 ns 348 ns +(0,55 ns/pF) CL
HIGH to LOW
LOW to HIGH 10 150 300 ns 139 ns +(0,23 ns/pF) CL
15 110 220 ns 102 ns +(0,16 ns/pF) CL
RS →O
210 selected 5 tPHL;
tPLH
425 850 ns 398 ns +(0,55 ns/pF) CL
HIGH to LOW
LOW to HIGH 10 165 330 ns 154 ns +(0,23 ns/pF) CL
15 120 240 ns 112 ns +(0,16 ns/pF) CL
RS →O
213 selected 5 tPHL;
tPLH
510 1020 ns 483 ns +(0,55 ns/pF) CL
HIGH to LOW
LOW to HIGH 10 190 380 ns 179 ns +(0,23 ns/pF) CL
15 135 270 ns 127 ns +(0,16 ns/pF) CL
RS →O
216 selected 5 tPHL;
tPLH
575 1150 ns 548 ns +(0,55 ns/pF) CL
HIGH to LOW
LOW to HIGH 10 210 420 ns 199 ns +(0,23 ns/pF) CL
15 150 300 ns 142 ns +(0,16 ns/pF) CL
Minimum clock 5 60 30 ns
pulse width; LOW 10 tWRSL 30 15 ns
15 24 12 ns
Minimum reset 5 60 30 ns
pulse width; HIGH 10 tWMRH 30 15 ns
15 24 12 ns
Maximum clock 5 8 16 MHz
pulse frequency 10 fmax 15 30 MHz
15 18 36 MHz
Oscillator frequency 5 90 kHz Rt=5 kΩ
10 fosc 90 kHz Ct= 1 nF
15 90 kHz RS= 10 kΩ
Oscillator frequency 5 8 kHz Rt= 56 kΩ
10 fosc 8 kHz Ct= 1 nF
15 8 kHz RS= 120 kΩ
