Pin 16 — D0 (LSB) — Data Bit 0 (Least Signifi-
cant Bit).
PIN ASSIGNMENTS
18–Pin Plastic DIP and SOIC
Pin 17 — N.C. — No Connection.
Pin 1 — IO1 — Inverted Current Output.
Pin 2 — IO2 — Current Output.
Pin 18 — VDD— +5V to +15V Power Supply.
Pin 19 — VREF— Voltage Reference Input.
Pin 20 — RFB— Feedback Resistor.
Pin 3 — GND — Analog Ground.
Pin4—D11 (MSB)—DataBit11(MostSignificant
Bit).
Pin 5 — D10 — Data Bit 10.
Pin 6 — D9 — Data Bit 9.
Pin 7 — D8 — Data Bit 8.
Pin 8 — D7 — Data Bit 7.
Pin 9 — D6 — Data Bit 6.
Pin 10 — D5— Data Bit 5.
Pin 11 — D4— Data Bit 4.
Pin 12 — D3— Data Bit 3.
Pin 13 — D2— Data Bit 2.
Pin 14 — D1— Data Bit 1.
FEATURES…
TheHS7541Aisalow–cost,highstabilitymono-
lithic 12–bit CMOS 4–quadrant multiplying
DAC. It is constructed using a proprietary low–
TCR thin–film process that requires no laser–
trimming to achieve 12–bit performance. With
its inherent high stability and a segmented (de-
coded) DAC architecture, the HS7541A retains
its performance over time and temperature. To
further improve reliability, all digital inputs are
protected against 2KV ESD. Each DAC is fully
characterized by all–codes testing to eliminate
any hidden errors.
Pin 15 — D0 (LSB) — Data Bit 0 (Least Significant
Bit).
The HS7541A consists of a highly stable thin–
film R–2R ladder network and twelve NMOS
current switches (please refer to the Block Dia-
gram on the first page of this data sheet). The
switchesaretemperaturecompensated,andtheir
“on” resistances are binarily scaled so that the
voltage drop across each switch is identical,
which contributes to the stability of the DAC.
The internal feedback resistor used in the output
current–to–voltage conversion by an external
op amp is matched to the R–2R ladder.
Pin 16 — VDD— +5V to +15V Power Supply.
Pin 17 — VREF— Voltage Reference Input.
Pin 18 — RFB— Feedback Resistor.
20–Pin Plastic LCC
Pin 1 — IO1 — Inverted Current Output.
Pin 2 — IO2 — Current Output.
Pin 3 — GND — Analog Ground.
Pin 4 — N.C. — No Connection.
Pin 5 — D11 (MSB) — Data Bit 11 (Most
Significant Bit).
CIRCUIT DESCRIPTION
General
Pin 6 — D10 — Data Bit 10.
Pin 7 — D9 — Data Bit 9.
Pin 8 — D8 — Data Bit 8.
Pin 9 — D7 — Data Bit 7.
Pin 10 — D6 — Data Bit 6.
Pin 11 — D5— Data Bit 5.
Pin 12 — D4— Data Bit 4.
Pin 13 — D3— Data Bit 3.
Pin 14 — D2— Data Bit 2.
Pin 15 — D1— Data Bit 1.
The HS7541A is a 12-bit multiplying D/A con-
verter consisting of a highly stable, SiChrome
thin-film R-2R resistor ladder network, and
twelvepairsofNMOScurrent-steeringswitches
on a monolithic chip.
Asimplifiedcircuit oftheHS7541A isshownin
Figure 1. The R-2R inverted ladder binarily
divides the input currents that are switched
between the IOUT1 and IOUT2 bus lines. This switch-
ing allows a constant current to be maintained in
each ladder leg independent of the input code.
HS7541A
12-Bit CMOS Multiplying DAC
© Copyright 2000 Sipex Corporation
4
SIPEX [ SIPEX CORPORATION ]
