DM74ALS169BM

DM74ALS169BM Datasheet


DM74ALS169B Synchronous Four-Bit Up/Down Counters

Part Datasheet
DM74ALS169BM DM74ALS169BM DM74ALS169BM (pdf)
Related Parts Information
DM74ALS169BMX DM74ALS169BMX DM74ALS169BMX
DM74ALS169BN DM74ALS169BN DM74ALS169BN
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DM74ALS169B Synchronous Four-Bit Up/Down Counters

DM74ALS169B Synchronous Four-Bit Up/Down Counters

These synchronous presettable counters feature an internal carry look ahead for cascading in high speed counting applications. The DM74ALS169B is a four-bit binary up/ down counter. The carry output is decoded to prevent spikes during normal mode of counting operation. Synchronous operation is provided so that outputs change coincident with each other when so instructed by count enable inputs and internal gating. This mode of operation eliminates the output counting spikes which are normally associated with asynchronous ripple clock counters. A buffered clock input triggers the four flip-flops on the rising positive going edge of clock input waveform.

These counters are fully programmable that is, the outputs may each be preset either HIGH or LOW. The load input circuitry allows loading with carry-enable output of cascaded counters. As loading is synchronous, setting up a low level at the load input disables the counter and causes the outputs to agree with the data inputs after the next clock pulse.

The carry look-ahead circuitry permits cascading counters for n-bit synchronous applications without additional gating. Both count enable inputs P and T must be LOW to count. The direction of the count is determined by the level of the up/down input. When the input is HIGH, the counter counts UP when LOW, it counts DOWN. Input T is fed forward to enable the carry outputs. The carry output thus enabled will produce a low level output pulse with a duration approximately equal to the high portion of the QA output when counting UP, and approximately equal to the low portion of the QA when counting DOWN. This low level overflow carry pulse can be used to enable successively cascaded stages. Transitions at the enable P or T inputs are allowed regardless of the level of the clock input.

The control functions for these counters are fully synchronous. Changes at control inputs enable P, enable T, load, up/down which modify the operating mode have no effect until clocking occurs. The function of the counter whether enabled, disabled, loading or counting will be dictated solely by the conditions meeting the stable setup and hold times.
s Switching specifications at 50 pF s Switching specifications guaranteed over full tempera-
ture and VCC range s Advanced oxide-isolated, ion-implanted Schottky TTL
process s Functionally and pin-for-pin compatible with Schottky
and low power Schottky TTL counterpart s Improved AC performance over Schottky and low power

Schottky counterparts s Synchronously programmable s Internal look ahead for fast counting s Carry output for n-bit cascading s Synchronous counting s ESD inputs
Ordering Code:

Order Number Package Number

Package Description

DM74ALS169BM

M16A
16-Lead Small Outline Integrated Circuit SOIC , JEDEC MS-012, Narrow

DM74ALS169BN

N16E
16-Lead Plastic Dual-In-Line Package PDIP , JEDEC MS-001, Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
2000 Fairchild Semiconductor Corporation DS006207

DM74ALS169B

Connection Diagram

Mode Select Table

LOAD EP

Action on Rising Clock Edge

X Load Pn Qn

H Count Up Increment

L Count Down Decrement

X No Change Hold

X No Change Hold

State Diagram

DM74ALS169B

Logic Diagram

DM74ALS169B

Absolute Maximum Ratings Note 1

Supply Voltage Input Voltage Operating Free Air Temperature Range Storage Temperature Range Typical

N Package M Package
7V 0°C to +70°C −65°C to +150°C
78.1°C/W 106.8°C/W

Note 1 The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The “Recommended Operating Conditions” table will define the conditions for actual device operation.

Recommended Operating Conditions

Parameter

Supply Voltage

HIGH Level Input Voltage

LOW Level Input Voltage

HIGH Level Output Current

LOW Level Output Current
fCLK

Clock Frequency

Setup Time Note 2

Data;

A, B, C, D

En P, En T

Load

Hold Time Note 2

Data;

A, B, C, D

En P, En T

Load
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Datasheet ID: DM74ALS169BM 513662