SA545
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FEATURES
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SA545, SA54L5
PULSE/DTMF SWITCHABLE DIALLERS WITH 10 REPERTORY
MEMORIES
Selectable Loop-disconnect (Pulse) or
DTMF (Tone) dialling modes
10 x 24 Digit Repertory Dialling Stores
24 Digit Last Number Redial (LNR)
Selectable Interdigit Pause (IDP)
500ms or 800ms
Operates with inexpensive single
contact keypad
On-chip Darlington transistor pair for
DTMF tone filtering
Low power CMOS technology enables
direct operation from Telephone line
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Selectable Break:Make Ratios 2:1 or
3:2
Uses inexpensive 560KHz ceramic
resonator
Earth Loop Recall and Timed Break
Recall (Timed Flash)
Low on-hook Supply Current Options
SA54X53 - 5µA @ 2.5V
SA54X56 - 1µA @ 2.5V
SA54X59 - 1µA @ 3.0V
Call, barring/locking feature available
on the SA54L5
Optional use of external capacitor for
oscillator
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Keypad switchable Loop-Disconnect to
DTMF during a call
PIN CONNECTIONS:
SA545
PIN CONNECTIONS:
SA54L5
M63-1961
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PDS039-SA545-001
REV. B
31-08-94
SA545
ABSOLUTE MAXIMUM RATINGS *
Parameter
Min
Typ
Max
6,5
V
DD
+0,3
1
0,1
0
70
125
Unit
V
V
V
mA
mA
mA
°C
°C
Notes
Supply Voltage V
DD
- V
SS
-0,3
Voltage on any pin (except HSW)
V
SS
-0,3
Voltage on pin HSW
V
SS
-0,3
Current at any pin
-1
(except HSW, FILTOUT and FILTIN)
Current at pin FILTOUT
0
Current at pin FILTIN
-5
Operating Temperature
-25
Storage Temperature
-55
See Note 1
* Stresses above those listed under "Absolute Maximum Ratings" may cause permanent
damage to the device. This a stress rating only. Functional operation of the device at
these or any other condition above those indicated in the operation sections of this
specification, is not implied. Exposure to Absolute Maximum Ratings for extended
periods may affect device reliability.
Note 1: A diode is internally connected between this pin and V
DD
. Provided current is
externally limited to 300µA max, no damage will occur.
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SA545
DC ELECTRICAL CHARACTERISTICS
(V
DD
= 2,5V at 25°C, unless otherwise specified)
Condition
Supply voltage:
on-hook
off-hook
Hookswitch input: on-hook
off-hook
0,8 V
DD
Supply Current: on-hook
SA54X53
<0.2
SA54X56
<0.2
SA54X59
<0.2
off-hook
1,5
MF tone sending
LD impulsing
Output High Voltage
2,2
(MASK, MUTE and IMP Outputs)
Output Low Voltage
(MASK, MUTE and IMP Outputs)
MF OUT d.c. Level During Tone Sending
0,9V
DD
MF OUT Output Resistance
'Key Pressed' Resistance
'Key Not Pressed' Resistance
Darlington Pair Current Gain
500
600
50,000
3
2
Min
1,8
2,4
Typ
Max Unit
5,7
V
5,7
V
0,2 V
DD
Notes
For memory retention
5
1
1
1,0
200
µA
µA
µA
µA
mA
µA
V
V
V
K
Ω
K
Ω
K
Ω
V
DD
= 2.5V
V
DD
= 2.5V
V
DD
= 3V
If MF OUT is low
I = -1mA
I = +1mA
0,3
2,5V<V
DD
<5,7V
2,5V<V
DD
<5,7V
I
e
=100µA,V
ce
=2V
AC ELECTRICAL CHARACTERISTICS
(V
DD
= 2,5V at 25°C, unless otherwise specified)
Condition
Oscillating Frequency
Tone Output: Low Group
High Group
High-to-Low Group Amplitude Ratio
Total harmonic Distortion: 0-4KHz
0-10KHz
0-50KHz
0-200KHz
Min
68
1,5
Typ
560
77
97
2
1,5
2,5
5,0
6,5
Max
Unit
kHz
mVrms
109 mVrms
2,5
dB
%
%
%
10
%
Notes
No Load
No Load
at MF OUT
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SA545
Keypad
Nominal frequency (Hz)
Deviation from nominal (%)
-,22
R1
697
R2
770
-,07
R3
852
-,10
R4
941
+,19
C1
1209
-,15
C2
-,17
C3
-,20
1336 1477
There will be an additional error due to any deviation in the oscillator frequency from 560
kHz.
FUNCTIONAL OVERVIEW
The SAMES SA545 is a family of keypad switchable Loop Disconnect (LD)/Dual Tone
multi-Frequency (DTMF) dialler devices for use in low-cost, dual dialling mode telephone
instruments.
The devices feature automatic storage of a single telephone number of up to 24 digits
for Last Number Redial (LNR) purposes as well as10 repertory dialling memories capable
of each storing 24 digits. The low current consumption of the SA545 ensures memory
retention while powered from the line.
Two modes of operation are available. The first is a LD/DTMF mode which operates
normally in LD mode, but can be switched temporarily via the keypad to DTMF mode
during a call. This mode has been optimised for applications such as home banking,
credit-card verification and other applications requiring low speed data communications.
The second mode allows DTMF dialling only.
The Lock function will be described in the Functional Description.
The SA545 family is pin compatible with SAMES SA541 family.
Ordering Information
SA54X5X/X
Lock Option
L : with (22 pin package)
Blank : without (20 pin package)
On-Hook Current Option
3 :
5µA @ 2.5V
6 :
1µA @ 2.5V
9 :
1µA @ 3V
Blank :
/1 :
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MF Digits dialled after */# not stored
All MF digits stored
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SA545
Block Diagram
Figure 1 depicts the SA545 block diagram, while Table 1 lists the respective pin functions
of the SA545 and SA54L5.
Figure 1: SA54X5 Block Diagram
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