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MAX8878EZK30+T ,Low-Noise, Low-Dropout, 150mA Linear Regulators with '2982 Pinout
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MAX8878EZK32+T ,Low-Noise, Low-Dropout, 150mA Linear Regulators with '2982 Pinout
MAX8878EZK32-T ,Low-Noise, Low-Dropout, 150mA Linear Regulators with '2982 Pinout
MAX8878EZK33+T ,Low-Noise, Low-Dropout, 150mA Linear Regulators with '2982 Pinout
MAX8878EZK36+T ,Low-Noise, Low-Dropout, 150mA Linear Regulators with '2982 Pinout
MAX4820EUP-MAX4821ETP
+3.3V/+5V, 8-Channel, Cascadable Relay Drivers with Serial/Parallel Interface
General DescriptionThe MAX4820/MAX4821 8-channel relay drivers offer
built-in kickback protection and drive +3.3V/+5V non-
latching or dual-coil-latching relays. These devices are
especially useful when driving +3V relays. Each inde-
pendent open-drain output features a 2Ωon-resistance
and is guaranteed to sink 70mA (min) of load current.
Both devices consume less than 50µA (max) quiescent
current and have 1µA output off-leakage current.
The MAX4820 features an SPI™-/QSPI™-/MICROWIRE™-
compatible serial interface. Input data is shifted into an 8-
bit shift register and latched to the outputs when CS
transitions from low to high. Each data bit in the shift reg-
ister corresponds to a specific output, allowing indepen-
dent control of all outputs.
The MAX4821 features a 4-bit (A0, A1, A2, LVL) paral-
lel-input interface. The first three bits (A0, A1, A2) deter-
mine the output address, and the fourth bit (LVL)
determines whether the selected output is switched on
or off. Data is latched to the outputs when CStransi-
tions from low to high.
Both devices feature separate set and reset functions
that allow the user to turn on or turn off all outputs simul-
taneously with a single control line. Built-in hysteresis
(Schmidt trigger) on all digital inputs allows this device
to be used with slow rising and falling signals, such as
those from optocouplers or RC power-up initialization
circuits. The MAX4820/MAX4821 are available in 20-pin
TSSOP and space-saving 20-pin thin QFN packages.
ApplicationsCentral Office
ATE
DSL, ADSL Line Cards
Industrial Equipment
E1/T1 Redundancy
Features8 Independent Output ChannelsBuilt-In Inductive Kickback ProtectionDrive +3V and +5V RelaysGuaranteed 70mA (min) Coil Drive CurrentSET
Function to Turn On All Outputs
SimultaneouslyRESET
Function to Turn Off All Outputs
SimultaneouslySPI-/QSPI-/MICROWIRE-Compatible Serial
Interface (MAX4820)Serial Digital Output for Daisy Chaining
(MAX4820)Parallel Interface (MAX4821)Low 50µA (max) Quiescent Supply CurrentSpace-Saving 20-Pin Thin QFN Package
MAX4820/MAX4821
+3.3V/+5V, 8-Channel, Cascadable Relay Drivers
with Serial/Parallel Interface
Pin Configurations19-2751; Rev 0; 1/03
Pin Configurations continued at end of data sheet.
Typical Application Circuits and Functional Diagrams
appear at end of data sheet.SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
MAX4820/MAX4821
+3.3V/+5V, 8-Channel, Cascadable Relay Drivers
with Serial/Parallel Interface
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICSStresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
(All voltages referenced to GND.)
VCC, COM..............................................................-0.3V to +6.0V
OUT_........................................................-0.3V to (VCOM + 0.3V)CS, SCLK, DIN, SET, RESET, A0, A1, A2, LVL......-0.3V to +6.0V
DOUT..........................................................-0.3V to (VCC + 0.3V)
Continuous OUT_ Current (all outputs turned on)............150mA
Continuous OUT_ Current (single output turned on)........300mA
Continuous Power Dissipation (TA= +70°C)
20-Lead Thin QFN
(derate 16.9mW/°C above +70°C).................................1350mW
θJA.........................................................................59.3°C/W
20-Pin TSSOP
(derate 21.7mW/°C above +70°C).................................1739mW
θJA............................................................................46°C/W
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Soldering Temperature (10s)...........................................+300°C
MAX4820/MAX4821
3.3V/+5V, 8-Channel, Cascadable Relay Drivers
with Serial/Parallel Interface
ELECTRICAL CHARACTERISTICS (continued)(VCC= +3V to +5.5V, VCOM= VCC, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
Note 2:After relay turn-off, inductive kickback may momentarily cause the voltage at OUT_ to exceed VCOM. This is considered part
of normal operation and will not damage the device.
MAX4820/MAX4821
+3.3V/+5V, 8-Channel, Cascadable Relay Drivers
with Serial/Parallel Interface
Typical Operating Characteristics(VCOM= VCC, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
MAX4820/MAX4821
3.3V/+5V, 8-Channel, Cascadable Relay Drivers
with Serial/Parallel Interface
INPUT LOGIC THRESHOLD
vs. SUPPLY VOLTAGEMAX4820 toc10
SUPPLY VOLTAGE (V)
INPUT LOGIC THRESHOLD (V)
2.35.5
ypical Operating Characteristics (continued)(VCOM= VCC, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
Pin Description
MAX4820/MAX4821
+3.3V/+5V, 8-Channel, Cascadable Relay Drivers
with Serial/Parallel Interface
Pin Description (continued)
Digital Interface
Serial Interface (MAX4820)The serial interface consists of an 8-bit shift register
and parallel latch controlled by SCLK and CS. The
input to the shift register is an 8-bit word. Each data bit
controls one of the eight outputs, with the most signifi-
cant bit (D7) corresponding to OUT8 and the least sig-
nificant bit (D0) corresponding to OUT1 (see Table 1).
When CSis low (device is selected), data at DIN is
clocked into the shift register synchronously with
SCLK’s rising edge. Driving CSfrom low to high latches
the data in the shift register to the parallel latch.
DOUT is the output of the shift register. Data appears
on DOUT synchronously with SCLK’s falling edge and
is identical to the data at DIN delayed by eight clock
cycles. When shifting the input data, D7 is the first bit in
and out of the shift register.
While CSis low, the switches always remain in their pre-
vious state. Drive CShigh after 8 bits of data have been
shifted in to update the output state and inhibit further
data from entering the shift register. When CSis high,
transitions at DIN and SCLK have no effect on the out-
put, and the first input bit (D7) is present at DOUT.
If the number of data bits entered while CSis low is
greater or less than 8, the shift register contains only
the last 8 data bits, regardless of when they were
entered.
The 3-wire serial interface is compatible with SPI, QSPI,
and MICROWIRE standards. The latch that drives the
analog switch is updated on the rising edge of CS,
regardless of SCLK’s state.
Parallel Interface (MAX4821)The parallel interface consists of three address bits
(A0, A1, A2) and one level selector bit (LVL). The
address bits determine which output is updated, and
the level bit determines whether the addressed output
is switched on (LVL = high) or off (LVL = low). When CS
is high, the address and level bits have no effect on the
state of the outputs. Driving CSfrom low to high latches
the address and level data to the parallel register and
updates the state of the outputs. Address data entered
after CSis pulled low is not reflected in the state of the
outputs following the next low-to-high transition on CS
(Figure 2).
MAX4820/MAX4821
3.3V/+5V, 8-Channel, Cascadable Relay Drivers
with Serial/Parallel InterfaceFigure 1. 3-Wire Serial-Interface Timing Diagram (MAX4820 only)
