MC1508-8 Datasheet, PDF (2/6 Pages) NXP Semiconductors – 8-bit multiplying D/A converter

Philips Semiconductors Linear Products
8-bit multiplying D/A converter
Product specification
MC1508-8/1408-8
BLOCK DIAGRAM
MSB
LSB
A₁
A₂
A₃
A₄
A₅
A₆
A₇
A₈
5
6
7
8
9
10
11
12
I_O
CURRENT SWITCHES
4
R-2R LADDER
BIAS
CURRENT
2
GND
V_REF
(+)
14
15
(–)
V_REF
REFERENCE
CURRENT
AMPLIFIER
13
V_CC
16
COMPEN
V_EE ³
NPN CURRENT SOURCE PAIR
CIRCUIT DESCRIPTION
feedback. The termination amplifier holds the parasitic capacitance
The MC1508/MC1408 consists of a reference current amplifier, an
R-2R ladder, and 8 high-speed current switches. For many
of the ladder at a constant voltage during switching, and provides a
low impedance termination of equal voltage for all legs of the ladder.
applications, only a reference resistor and reference voltage need
be added.
The R-2R ladder divides the reference amplifier current into
binarily-related components, which are fed to the remainder current
The switches are non-inverting in operation; therefore, a high state
on the input turns on the specified output current component.
The switch uses current steering for high speed, and a termination
amplifier consisting of an active load gain stage with unity gain
which is equal to the least significant bit. This current is shunted to
ground, and the maximum output current is 255/256 of the reference
amplifier current, or 1.992mA for a 2.0mA reference amplifier current
if the NPN current source pair is perfectly matched.
ABSOLUTE MAXIMUM RATINGS
SYMBOL
PARAMETER
RATING
V_CC
V_EE
V₅ – V₁₂
V_O
I₁₄
V₁₄, V₁₅
P_D
Positive power supply voltage
Negative power supply voltage
Digital input voltage
Applied output voltage
Reference current
Reference amplifier inputs
Maximum power dissipation,
T_A = 25°C (still-air)¹
F package
+5.5
–16.5
0 to V_CC
–5.2 to +18
5.0
V_EE to V_CC
1190
N package
1450
D package
1080
T_SOLD
T_A
Lead soldering temperature (10 sec)
Operating temperature range
MC1508
300
300
–55 to +125
MC1408
0 to +75
T_STG
Storage temperature range
-65 to +150
NOTES:
1. Derate above 25°C, at the following rates: F package at 9.5mW/°C; N package at 11.6mW/°C; D package at 8.6mW/°C
UNIT
V
V
V
V
mA
mW
mW
mW
°C
°C
°C
°C
°C
August 31, 1994
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