MAX6920AWP+ Maxim Integrated Products, MAX6920AWP+ Datasheet - Page 7

• Manufacturer Part Number: MAX6920AWP+
• Description: IC DRVR VFD TUBE SRL 20-SOIC
• Manufacturer: Maxim Integrated Products

Specifications of MAX6920AWP+

• Display Type: Vacuum Fluorescent (VF)
• Interface: 4-Wire Serial
• Current - Supply: 1mA
• Voltage - Supply: 8 V ~ 76 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 20-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Configuration: -
• Digits Or Characters: -
• Lead Free Status / Rohs Status: Details

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A fifth input pin, BLANK, can be taken high to force out-
puts OUT0 to OUT11 low, without altering the contents
of the output latches. When the BLANK input is low,
outputs OUT0 to OUT11 follow the state of the output
latches. A common use of the BLANK input is PWM
intensity control.
The BLANK input’s function is independent of the oper-
ation of the serial interface. Data can be shifted into the
serial interface shift register and latched regardless of
the state of BLANK.
The MAX6920 is written using the following sequence:
1)
2)
3)
Table 1. 4-Wire Serial Interface Truth Table
L = Low logic level.
H = High logic level.
X = Don’t care.
P = Present state (shift register).
R = Previous state (latched).
SERIAL
INPUT
DATA
Writing Device Registers Using the 4-Wire
DIN
H
L
X
DIN is the interface data input, and must be stable
when it is sampled on the rising edge of CLK.
DOUT is the interface data output, which shifts
data out from the MAX6920’s 12-bit shift register
on the falling edge of CLK. Data at DIN is propa-
gated through the shift register and appears at
DOUT (20 CLK cycles + t
Take CLK low.
Clock 12 bits of data in order D11 first to D0 last
into DIN, observing the data setup and hold times.
Load the 12 output latches with a falling edge
on LOAD.
CLOCK
INPUT
CLK
SHIFT REGISTER CONTENTS
D0 D1 D2 … Dn-1
R0 R1 R2 … Rn-1
P0
H
L
X
_______________________________________________________________________________________
R0 R1 … Rn-2 Rn-1
R0 R1 … Rn-2 Rn-1
P1 P2 … Pn-1
X
X
…
DO
) later.
X
Serial Interface
12-Output, 76V, Serial-Interfaced
Dn
Rn
Pn
X
INPUT
LOAD
LOAD D0 D1 D2 … Dn-1 Dn
H
L
R0 R1 R2
P0 P1 P2
X
LATCH CONTENTS
X
LOAD may be high or low during a transmission. If
LOAD is high, then the data shifted into the shift regis-
ter at DIN appears at the OUT0 to OUT11 outputs.
CLK and DIN may be used to transmit data to other
peripherals. Activity on CLK always shifts data into the
MAX6920’s shift register. However, the MAX6920 only
updates its output latch on the rising edge of LOAD,
and the last 12 bits of data are loaded. Therefore, multi-
ple devices can share CLK and DIN as long as they
have unique LOAD controls.
The outputs are CMOS drivers, and have a resistive
characteristic. The typical and maximum sink and
source output resistances can be calculated from the
V
resistance to determine the output voltage drop at dif-
ferent output currents.
The continuous current source capability is 40mA per
output. Outputs may drive up to 75mA as a repetitive
peak current, subject to the on time (output high) being
no longer than 1ms, and the duty cycle being such that
the output power dissipation is no more than the dissipa-
tion for the continuous case. The repetitive peak rating
allows outputs to drive a higher current in multiplex grid
driver applications, where only one grid is on at a time,
and the multiplex time per grid is no more than 1ms.
X
H
and V
Determining Driver Output Voltage Drop
… Rn-1 Rn
… Pn-1 Pn
…
L
X
electrical characteristics. Use this calculated
X
VFD Tube Driver
BLANKING
BLANK
INPUT
H
L
Output Current Ratings
D0 D1 D2 …
P0 P1 P2
L
OUTPUT CONTENTS
L
L
…
…
Dn-1 Dn
Pn-1 Pn
L
L
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