Allegro A6277SLW, A6277SA, A6277ELW, A6277EA Datasheet

Data Sheet

26185.202

8-BIT SERIAL-INPUT, CONSTANT­CURRENT LATCHED LED DRIVER

Always order by complete part number, e.g., A6277EA .

The A6277x is specifically designed for LED-display applications.
Each BiCMOS device includes an 8-bit CMOS shift register, accompa­nying data latches, and eight npn constant-current sink drivers. Two
package styles and two operating temperature ranges are available.

The CMOS shift register and latches allow direct interfacing with
microprocessor-based systems. With a 5 V logic supply, typical serial
data-input rates are up to 20 MHz. The LED drive current is deter­mined by the user’s selection of a single resistor. A CMOS serial data
output permits cascade connections in applications requiring additional
drive lines. For inter-digit blanking, all output drivers can be disabled
with an ENABLE input high. In addition, a HIGH/LOW function
enables full selected current with the application of a logic low, or 50%
selected current with the application of a logic high.

The first character of the part number suffix determines the device
operating temperature range. Suffix ‘E–’ is for -40°C to +85°C, and
suffix ‘S–’ is -20°C to +85°C. Two package styles are provided for
through-hole DIP (suffix ‘–A’) or surface-mount SOIC (suffix ‘–LW’)
applications. The copper lead frame and low logic-power dissipation
allow the dual in-line package to sink 122 mA through all outputs
continuously over the operating temperature range (1.0 V drop,
+85°C).

Note that the A6277EA (DIP) and the A6277ELW
(SOIC) are electrically identical and share a
common terminal number assignment.

ABSOLUTE MAXIMUM RATINGS

Supply Voltage, VDD...................... 7.0 V

Output Voltage Range,

V

O

............................ -0.5 V to +24 V

Output Current, I

O

....................... 150 mA

Input Voltage Range,

V

I

.................... -0.4 V to VDD + 0.4 V

Package Power Dissipation,

P

D

..................................... See Graph

Operating Temperature Range, T

A

Suffix ‘S-’ ................ -20°C to +85°C

Suffix ‘E-’ ................ -40

°C to +85°C

Storage Temperature Range,

T

S

........................... -55°C to +150°C

Caution: These CMOS devices have input
static protection (Class 2) but are still suscep­tible to damage if exposed to extremely high
static electrical charges.

6277

PRELIMINARY INFORMATION

(Subject to change without notice)

July 20, 2000

FEATURES

■ To 150 mA Constant-Current Outputs

■ 24 V Outputs

■ Under-Voltage Lockout

■ Low-Power CMOS Logic and Latches

■ High Data Input Rate

■ Similar to Toshiba TD62715FN

■ High/Low Output Current Function

A6277ELW

REGISTER

LATCHES

5

10

11

12

13

14

15

6

7

8

9

16

POWER
GROUND

POWER

GROUND

HIGH/LOW

(CURRENT)

OUT

1

OUT

2

Dwg. PP-029-17A

OUT

0

OUT

4

OUT

6

OUT

5

OUT

3

OUT

7

LOGIC

GROUND

1

2

3

17

19

4

18

20

SERIAL
DATA OUT

LOGIC
SUPPLY

SERIAL

DATA IN

OUTPUT
ENABLE

LATCH

ENABLE

CLOCK

CK

V

DD

OE

R

EXT

I

REGULATOR

L

O

SUB

SUB

SERIAL
DATA OUT

2

1

FF

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

6277

8-BIT SERIAL-INPUT,
CONSTANT-CURRENT
LATCHED LED DRIVER

2

Copyright © 2000, Allegro MicroSystems, Inc.

50 75 100 125 150

2.5

0.5

0

ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS

AMBIENT TEMPERATURE IN °C

2.0

1.5

1.0

25

SUFFIX 'A', R = 55°C/W

θJA

Dwg. GP-018-1

SUFFIX 'LW', R = 70°C/W

θJA

FUNCTIONAL BLOCK DIAGRAM

MOS

BIPOLAR

LOGIC

GROUND

LATCH

ENABLE

OUTPUT ENABLE
(ACTIVE LOW)

SERIAL DATA
OUT

CLOCK

SERIAL

DATA IN

SERIAL-PARALLEL SHIFT REGISTER

LATCHES

V

DD

LOGIC
SUPPLY

R

OUT0OUT

1

Dwg. FP-013-7

OUT

2

OUT

N

I

REGULATOR

O

UVLO

POWER

GROUND

POWER

GROUND

SUB

HIGH/LOW
(CURRENT)

FF

SERIAL DATA
OUT

EXT

1

2

6277

8-BIT SERIAL-INPUT,

CONSTANT-CURRENT

LATCHED LED DRIVER

www.allegromicro.com

3

TRUTH TABLE

Serial Shift Register Contents Serial Latch Latch Contents Output Output Contents
Data Clock Data Enable Enable
Input Input I

1I2I3

... I

N-1IN

Output Input I1I2I3... I

N-1IN

Input I1I2I3... I

N-1

I

N

HHR

1R2

... R

N-2RN-1RN-1

LLR

1R2

... R

N-2RN-1RN-1

XR

1R2R3

... R

N-1RN

R

N

XXX...X X X L R1R2R3... R

N-1 RN

P1P2P3... P

N-1PN

P

N

HP1P2P3... P

N-1 PN

LP1P2P3... P

N-1 PN

XXX...X X H H H H ... H H

L = Low Logic (Voltage) Level H = High Logic (Voltage) Level X = Irrelevant P = Present State R = Previous State

CLOCK and SERIAL DATA IN SERIAL DATA OUT

LATCH ENABLE and HIGH/LOWOUTPUT ENABLE (active low)

Dwg. EP-010-6

IN

V

DD

Dwg. EP-010-7

IN

V

DD

Dwg. EP-010-5

IN

V

DD

Dwg. EP-063-1

V

DD

OUT

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

6277

8-BIT SERIAL-INPUT,
CONSTANT-CURRENT
LATCHED LED DRIVER

4

ELECTRICAL CHARACTERISTICS at TA = +25°C, V

H/L

= VDD = 5 V (unless otherwise noted).

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Unit

Supply Voltage Range V

DD

Operating 4.5 5.0 5.5 V

Under-Voltage Lockout V

DD(UV)

VDD = 0 to 5 V 3.4 – 4.0 V

Output Current I

O

VCE = 1.0 V, R

EXT

= 160 Ω 100 120 140 mA

(any single output)

VCE = 0.4 V, R

EXT

= 470 Ω 34 42 48 mA

Output Current Matching ∆I

O

0.4 V ≤ V

CE(A)

= V

CE(B)

≤ 1.0 V:

(difference between any R

EXT

= 160 Ω – ±1.5 ±6.0 %

two outputs at same VCE)

R

EXT

= 470 Ω – ±1.5 ±6.0 %

Output Leakage Current I

CEX

VOH = 20 V – 1.0 5.0 µA

Logic Input Voltage V

IH

0.7V

DD

––V

V

IL

– – 0.3V

DD

V

SERIAL DATA OUT Voltage V

OL

IOL = 1.0 mA – – 0.4 V

(SDO1 & SDO2)

V

OH

IOH = -1.0 mA 4.6 – – V

Input Resistance R

I

ENABLE input, pull up 150 300 600 kΩ

LATCH & HIGH/LOW inputs, pull down 100 270 400 kΩ

Supply Current I

DD(OFF)

R

EXT

= open, VOE = 5 V – 0.8 1.6 mA

R

EXT

= 470 Ω, VOE = 5 V 3.5 6.5 9.5 mA

R

EXT

= 160 Ω, VOE = 5 V 14 17 22 mA

I

DD(ON)

R

EXT

= 470 Ω, VOE = 0 V 5.0 10 15 mA

R

EXT

= 160 Ω, VOE = 0 V 20 27 40 mA

Typical Data is at VDD = 5 V and is for design information only.