General Description
The MAX4896 8-channel relay and load driver is
designed for medium voltage applications up to 50V.
This device is offered in a 20-pin, 5mm x 5mm TQFN
package, resulting in substantial board space savings.
The MAX4896 8-channel relay driver offers built-in
inductive kickback protection, drive for latching/
nonlatching or dual-coil relays, and open-load and
short-circuit fault detection.The MAX4896 also protects
against overcurrent conditions. Each independent
open-drain output features a 3Ω(typ) on-resistance,
and is guaranteed to sink 200mA of load current
(VS≥4.5V).
A built-in overvoltage protection clamp handles kick-
back-voltage transients, which are common when dri-
ving inductive loads. Thermal-shutdown circuitry shuts
off all outputs (OUT_) when the junction temperature
exceeds +160°C. The MAX4896 employs a reset input
that allows the user to turn off all outputs simultaneously
with a single control line.
The MAX4896 includes a 10MHz SPI™-/QSPI™-/
MICROWIRE™-compatible serial interface. The serial
interface is compatible with TTL-/CMOS-logic voltage
levels and operates with a single +2.7V to +5.5V sup-
ply. In addition, the SPI output data can be used for
diagnostics purposes including open-load and short-
circuit fault detection.
The MAX4896 is offered in the extended (-40°C to
+85°C) and automotive (-40°C to +125°C) operating
temperature ranges.
Features
Supports Up to 50V Continuous Drain-to-Source
Voltage
Guaranteed Drive Current:
VS≥4.5V
200mA (All Channels On)
410mA (Individual Channels)
VS≤3.6V
100mA
Built-In Output Clamp Protects Against Inductive
Kickback
+2.7V to +5.5V Logic Supply Voltage
RESET Input Turns Off All Outputs
Simultaneously
Built-in Power-On Reset
Automotive Temperature Range
(-40°C to +125°C)
SPI-/QSPI-/MICROWIRE-Compatible Serial
Interface
Serial Digital Output for Daisy Chaining and
Diagnostics
FLAG Output for µP Interrupt
Open-Load and Short-Circuit Detection and
Protection
Thermal Shutdown
Low 100µA (max) Quiescent Supply Current
Space-Saving, 5mm x 5mm, 20-Pin TQFN Package
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
1
PART TEMP RANGE PIN-PACKAGE
MAX4896ETP+
-40°C to +85°C 20 TQFN-EP*
(5mm x 5mm)
MAX4896ATP+
-40°C to +125°C
20 TQFN-EP*
(5mm x 5mm)
Ordering Information
MAX4896
OUT8
SCLK
CS
DIN
RESET
DOUT
PGNDGNDSLPD
Vcc = 2.7V TO 5.5V
0.1µF
VS
RELAY
COIL 8
OUT1
PDCD
VRELAY
VRELAY
FLAG
µC
INT
RELAY
COIL 1
Typical Operating Circuit Applications
19-3843; Rev 3; 7/12
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
*
EP = Exposed paddle
+
Denotes a lead(Pb)-free/RoHS-compliant package.
Industrial Equipment Automotive Relay Control
White Goods ATE
Power-Grid Monitoring
and Protection Equipment
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
Pin Configuration appears at end of data sheet.
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
2
ABSOLUTE MAXIMUM RATINGS
Stresses 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.
Note 1: Maximum continuous current at a given temperature must be calculated such that the maximum continuous power
dissipation for the package is not exceeded.
Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
(All voltages referenced to GND.)
VS......................................................................... -0.3V to +7.0V
OUT_ ....................................................................(-0.3V to +50V)
Continuous OUT_ Voltage ...................................................+50V
CS, SCLK, DIN, RESET, SPLD, PDCD ..................-0.3V to +7.0V
DOUT ............................................................-0.3V to (VS+ 0.3V)
PGND to GND……………………………………..(-0.3V to +0.3V)
Continuous OUT_ Current, TA= +25°C (Note 1)
All Outputs On..................................................................210mA
Single Output On .............................................................420mA
Continuous Power Dissipation (TA= +70°C)
20-Pin TQFN (derate 21.3mW/°C above +70°C) ......1702mW
Maximum Output Clamp Energy (EOUT_) ...........................30mJ
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
ELECTRICAL CHARACTERISTICS
(VS= +2.7V to +5.5V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Operating Voltage VS2.7 5.5 V
VS = 3.6V 5 70
Quiescent Current ICC IOUT_ = 0, logic inputs =
0 or VS, RESET = low VS = 5V 10 100 µA
Dynamic Average Supply
Current ISfSCLK = 10MHz, fDIN = 0.5 x fCLK,
COUT = 50pF, VS = 5.5V 6mA
Thermal Shutdown TSHD +160 °C
Thermal-Shutdown Hysteresis TSHDH 20 °C
Power-On Reset VRST VS falling 1.8 2.05 2.3 V
Power-On-Reset Hysteresis VRSTH 140 mV
DIGITAL INPUTS (SCLK, DIN, CS, RESET, PDCD, SPLD)
VS = 2.7V to 3.6V 2.0
Input Logic-High Voltage VIH VS = 4.5V to 5.5V 2.4
V
VS = 2.7V to 3.6V 0.6
Input Logic-Low Voltage VIL VS = 4.5V to 5.5V 0.8 V
Input Logic Hysteresis VHYST 230 mV
Input Leakage Currents ILEAK Input voltages = 0 or +5.5V -1 +1 µA
Input Capacitance CIN 10 pF
PACKAGE THERMAL CHARACTERISTICS (Note 2)
20 TQFN-EP
Junction-to-Ambient Thermal Resistance (θJA)...............29°C/W
Junction-to-Case Thermal Resistance (θJC)......................2°C/W
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
3
ELECTRICAL CHARACTERISTICS (continued)
(VS= +2.7V to +5.5V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
RELAY OUTPUT DRIVERS (OUT1–OUT8)
TJ = +25°C 5 6
TJ = +125°C 11
IOUT = 50mA,
VS = 2.7V
TJ = +150°C 12
TJ = +25°C 3 4
TJ = +125°C 7
OUT_ ON Resistance RON
IOUT = 100mA,
VS = 4.5V
TJ = +150°C 8
Ω
IOUT Off-Leakage Current ILEAK PDCD = high or RESET = low, all outputs
off -1 +1 µA
OUT Clamping Voltage VCLAMP (Note 4) 50 75 V
OUT Current-Limit Threshold ILIM VS ≥ 4.5V 400 960 mA
OUT Capacitance VOUT = 16V, f = 1MHz 30 pF
DIAGNOSTIC
Open-Load Detection Voltage
Threshold VDS
(
OL
)
OUT_ falling 0.75 1 1.15 V
Open-Load Detection-Voltage-
Threshold Hysteresis VDS
(
OLH
)
40 mV
OUT_ Pulldown Current IPD
(
OL
)
PDCD = low 150 300 500 µA
Fault Delay/Filtering Time tD
(
FAULT
)
From rising edge at CS at 50% to valid
diagnostic data 30 90 280 µs
DIGITAL OUTPUT (DOUT, FLAG)
2.7V ≤ VS ≤ 3.6V, ISINK = 0.3mA 0.4
DOUT Low Voltage VOL 4.5V ≤ VS ≤ 5.5V, ISINK = 0.5mA 0.4 V
2.7V ≤ VS ≤ 3.6V, ISOURCE = 0.25mA VS - 0.5
DOUT High Voltage VOH 4.5V ≤ VS ≤ 5.5V, ISOURCE = 0.4mA VS - 0.5 V
FLAG Low Voltage ISINK = 0.5mA 0.4 V
FLAG Off-Leakage Current 4.5V ≤ VS ≤ 5.5V, VFLAG = 5.5V -1 +1 µA
TIMING
From rising edge of CS at 50% to VOUT_
= 90%VP, VP = 15V, RL = 300Ω,
CL = 50pF, 2.7V ≤ VS < 3.6V
20
Turn-On Time (OUT_) tON
From rising edge of CS at 50% to VOUT_
= 90%VP, VP =16V, RL = 150Ω,
CL = 50pF, 4.5V ≤ VS ≤ 5.5V
10
µs
From rising edge of CS at 50% to VOUT_
= 10%VP, VP = 15V, RL = 300Ω,
CL = 50pF, 2.7V ≤ VS < 3.6V
15
Turn-Off Time (OUT_) tOFF
From rising edge of CS at 50% to VOUT_
= 90%VP, VP = 16V, RL = 150Ω,
CL = 50pF, 4.5V < VS ≤ 5.5V
10
µs
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
4
ELECTRICAL CHARACTERISTICS (continued)
(VS= +2.7V to +5.5V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
2.7V ≤ VS < 3.6V 0 6
TA = +85°C 4.5V ≤ VS ≤ 5.5V 11
2.7V ≤ VS ≤ 3.6V 0 5
SCLK Frequency fSCLK
TA = +125°C 4.5V ≤ VS ≤ 5.5V 10
MHz
2.7V ≤ VS ≤ 3.6V 200
Cycle Time tCH + tCL 4.5V ≤ VS ≤ 5.5V 100 ns
2.7V ≤ VS ≤ 3.6V 100
CS Fall-to-SCLK Rise Setup tCSS 4.5V ≤ VS ≤ 5.5V 50 ns
2.7V ≤ VS ≤ 3.6V 100
CS Rise-to-SCLK Hold tCSH 4.5V ≤ VS ≤ 5.5V 50 ns
2.7V ≤ VS ≤ 3.6V 80
SCLK High Time tCH 4.5V ≤ VS ≤ 5.5V 40 ns
2.7V ≤ VS ≤ 3.6V 80
SCLK Low Time tCL 4.5V ≤ VS ≤ 5.5V 40 ns
2.7V ≤ VS ≤ 3.6V 40
Data Setup Time tDS 4.5V ≤ VS ≤ 5.5V 20 ns
2.7V ≤ VS ≤ 3.6V 5
Data Hold Time tDH 4.5V ≤ VS ≤ 5.5V 0 ns
2.7V ≤ VS ≤ 3.6V 70
SCLK Fall-to-DOUT Valid tDO
50% of SCLK to
20% of VS falling
edge, CL = 50pF,
50% at SCLK to
80% of VS rising
edge
4.5V ≤ VS ≤ 5.5V 30
ns
2.7V ≤ VS ≤ 3.6V 2
Rise Time (DIN, SCLK, CS,
RESET)tSCR
20% of VS to 70%
of VS, CL = 50pF
(Note 5) 4.5V ≤ VS ≤ 5.5V 2
µs
2.7V ≤ VS ≤ 3.6V 2
Fall Time (DIN, SCLK, CS,
RESET)tSCF
20% of VS to 70%
of VS, CL = 50pF
(Note 5) 4.5V ≤ VS ≤ 5.5V 2
µs
RESET Min Pulse Width tRW 70 ns
Note 3: Specifications at -40°C are guaranteed by design and not production tested.
Note 4: The output stages are compliant with the transient immunity requirements, as specified in ISO 7637 Part 3 with test pulses 1,
2, 3a, and 3b.
Note 5: Guaranteed by design.
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
5
QUIESCENT CURRENT
vs. SUPPLY VOLTAGE
MAX4896 toc01
SUPPLY VOLTAGE (V)
QUIESCENT CURRENT (µA)
5.14.73.9 4.33.53.1
1
2
3
4
5
6
7
8
9
10
11
12
0
2.7 5.5
TA = +125°C
ALL LOGIC INPUTS = VS
TA = +85°C
TA = +25°C
TA = -40°C
fCLK (MHz)
SUPPLY CURRENT
vs. fCLK
MAX4896 toc02
SUPPLY CURRENT (mA)
3.0
3.5
4.0
4.5
5.0
5.5
6.0
2.5
2.0
0.1 1 10
VS = 5V
VS = 2.7V
VS = 3.3V
fDIN = 0.5 x fCLK
ON-RESISTANCE
vs. SUPPLY VOLTAGE
MAX4896 toc 03
SUPPLY VOLTAGE (V)
RON (Ω)
5.14.73.9 4.33.53.1
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
IOUT_SINK = 100mA
2.0
2.7 5.5
IOUT_SINK = 50mA
MAX4896 toc04
TEMPERATURE (°C)
RON (Ω)
1109580655035205-10-25
2
3
4
5
6
7
8
IOUT_SINK = 50mA
1
-40 125
ON-RESISTANCE
vs. TEMPERATURE
VS = 2.7V
VS = 5V
VS = 5.5V
VS = 3.3V
ON-RESISTANCE
vs. TEMPERATURE
MAX4896 toc05
TEMPERATURE (°C)
RON (Ω)
1109580655035205-10-25
2
3
4
5
6
7
8
VS = 2.7V
1
-40 125
VS = 3.3V VS = 5V
VS = 5.5V
IOUT_SINK = 100mA
POWER-ON RESET VOLTAGE
vs. TEMPERATURE
MAX4896 DS toc06
TEMPERATURE (°C)
POWER-ON-RESET VOLTAGE (V)
1109580655035205-10-25
2.02
2.04
2.06
2.08
2.10
2.12
2.14
2.00
-40 125
OUTPUT OFF LEAKAGE CURRENT
vs. SUPPLY VOLTAGE
MAX4896 toc07
SUPPLY VOLTAGE (V)
OUTPUT OFF LEAKAGE (pA)
5.14.73.9 4.33.53.1
10
20
30
40
50
60
70
80
90
100
VOUT = 50V
0
2.7 5.5
VOUT = 24V
VOUT = 12V
TEMPERATURE (°C)
OUT LEAKAGE CURRENT (nA)
OUT LEAKAGE CURRENT
vs. TEMPERATURE
100
PDCD = VS
10
1
0.1
0.01
0.001
1109580655035205-10-25-40 125
MAX4896 DS toc08
VOUT = 50V
VOUT = 12V
VOUT = 24V
INPUT LOGIC THRESHOLD
vs. SUPPLY VOLTAGE
MAX4896 toc09
SUPPLY VOLTAGE (V)
INPUT LOGIC THRESHOLD (V)
5.14.73.1 3.5 3.9 4.3
0.75
1.00
1.25
1.50
1.75
2.00
2.25
2.50
0.50
2.7 5.5
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
6
TURN-ON/TURN-OFF DELAY TIME
vs. SUPPLY VOLTAGE
MAX4896 toc10
SUPPLY VOLTAGE (V)
tON/tOFF DELAY TIME (µs)
3.53.43.33.23.13.02.92.8
0.5
1.0
1.5
2.0
2.5
3.0
0
2.7 3.6
VOUT = 15V RL = 300Ω
CL = 50pF
tOFF
tON
TURN-ON/TURN-OFF DELAY TIME
vs. SUPPLY VOLTAGE
MAX4896 toc11
SUPPLY VOLTAGE (V)
tON/tOFF DELAY TIME (µs)
5.35.14.94.7
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0
4.5 5.5
tOFF
tON
RL = 150Ω
CL = 50pF
VOUT = 50V
OUTPUT CURRENT LIMIT (mA)
450
500
550
600
700
650
750
800
400
OUT_ CURRENT LIMIT
vs. SUPPLY VOLATGE
MAX4896 toc12
SUPPLY VOLTAGE (V)
5.35.14.94.74.5 5.5
TA = -40°C
TA = +125°C
TA = +85°C
TA = +25°C
OUT CLAMP VOLTAGE
vs. TEMPERATURE
MAX4896 toc13
TEMPERATURE (°C)
0UT CLAMP VOLTAGE (V)
1109565 80-10 5 20 35 50-25
64.2
64.4
64.6
64.8
65.0
65.2
65.4
65.6
65.8
66.0
64.0
-40 125
BACK-EMF CLAMPING
WITH STANDARD +12V RELAY
MAX4896 toc14
RESET
OUT
(20V/div)
(2V/div)
1ms/div
VS = 3.3V
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
7
Pin Description
PIN NAME FUNCTION
1RESET Reset Input. Drive RESET low to clear all latches and registers (all outputs are turned off). All OUT
pulldown currents are disabled when RESET = low.
2CS Chip Select Input. Drive CS low to select the device. When CS is low, data at DIN is clocked into the
8-bit shift register on SCLK’s rising edge. Drive CS from low to high to latch the data to the registers.
3 DIN Serial Data Input
4 SCLK Serial Clock Input
5DOUT
Serial Data Output. DOUT is the output of the 8-bit shift register. This output can be used to daisy
chain multiple MAX4896s. The data at DOUT appears synchronous to SCLK’s falling edge.
6 PDCD Pulldown Current Disable. Drive PDCD high to disable OUT’s pulldown current source. Drive PDCD
low to enable OUT_ pulldown current source. PDCD must be low to detect an open-load fault.
7 SPLD
Short-Protection Latch-Off Disable Input. Drive SPLD high to disable the built-in short-circuit
protection latch-off feature. When SPLD is low, an overloaded channel is turned off immediately. See
the Output Short-Circuit/Current-Limiting Protection section.
8 OUT8 Open-Drain Output 8. Connect OUT8 to the low side of a relay coil. OUT8 is pulled to PGND when
activated and is otherwise high impedance.
9 OUT7 Open-Drain Output 7. Connect OUT7 to the low side of a relay coil. OUT7 is pulled to PGND when
activated and is otherwise high impedance.
10, 16 PGND Power Ground. PGND is the ground return path for the output sinks. Connect PGND pins together
and to GND.
11 OUT6 Open-Drain Output 6. Connect OUT6 to the low side of a relay coil. OUT6 is pulled to PGND when
activated and is otherwise high impedance.
12 OUT5 Open-Drain Output 5. Connect OUT5 to the low side of a relay coil. OUT5 is pulled to PGND when
activated and is otherwise high impedance.
13 GND Ground
14 OUT4 Open-Drain Output 4. Connect OUT4 to the low side of a relay coil. OUT4 is pulled to PGND when
activated and is otherwise high impedance.
15 OUT3 Open-Drain Output 3. Connect OUT3 to the low side of a relay coil. OUT3 is pulled to PGND when
activated and is otherwise high impedance.
17 OUT2 Open-Drain Output 2. Connect OUT2 to the low side of a relay coil. OUT2 is pulled to PGND when
activated and is otherwise high impedance.
18 OUT1 Open-Drain Output 1. Connect OUT1 to the low side of a relay coil. OUT1 is pulled to PGND when
activated and is otherwise high impedance.
19 VSInput Supply Voltage. Bypass VS to GND with a 0.1µF capacitor.
20 FLAG Open-Drain Fault Output. FLAG asserts low when a fault occurs at OUT1–OUT8.
—EP
Exposed Paddle. Internally connected to GND. Connect to a large PCB ground plane to improve
thermal dissipation. Enhances thermal conductivity; not intended as an electrical connection point.
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
8
The MAX4896 is an 8-channel relay and load driver for
medium voltage applications up to 50V. The MAX4896
features built-in inductive kickback protection, drive for
latching/nonlatching, or dual-coil relays and an internal
register for detecting open-load and short-circuit faults.
Each independent open-drain output features a 3Ωon-
resistance and is guaranteed to sink 400mA at VS≥
4.5V, and 100mA at VS≤3.6V.
The MAX4896 also incorporates a logic input (PDCD)
that allows the device to continue operating when an
overcurrent condition lasts longer than the 280µs (max)
fault delay time. A built-in overvoltage protection clamp
handles kickback voltage transients, which are com-
mon when driving inductive loads. Thermal-shutdown
circuitry shuts off all outputs (OUT_) when the junction
temperature exceeds +160°C.
The MAX4896 employs a reset input that allows the
user to turn off all outputs simultaneously with a single
control line.
The MAX4896 includes a 10MHz SPI-/QSPI-/MICROWIRE-
compatible serial interface. The serial interface is compat-
ible with TTL-/CMOS-logic voltage levels and operates
with a single +2.7V to +5.5V supply.
Serial Interface
The serial interface consists of an 8-bit input shift regis-
ter, a parallel latch (output control register) controlled
by SCLK and CS, and an output status register contain-
ing diagnostics information. The input to the shift regis-
ter is an 8-bit word. Each data bit controls one of the
eight outputs, with the most significant bit (D7) corre-
sponding to OUT8, and the least significant bit (D0)
corresponding to OUT1 (see Table 1). When CS is low,
data at DIN is clocked into the shift register synchro-
nously with SCLK’s rising edge. Driving CS from low to
high latches the data in the shift register to the output
control register.
DOUT is the output of the internal output status register
for diagnostics purposes (see Figure 2 and Tables 2
and 3). Status data for each channel is transferred to
the shift register at the falling edge of CS. The data bits
contained in the shift register are then transferred to the
DOUT output synchronously with SCLK’s falling edge.
While CS is low, the switches always remain in their
previous states. Drive CS high after 8 bits of data have
been shifted in to update the output state, and to further
inhibit data from entering the shift register. When CS is
high, transitions at DIN and SCLK have no effect on the
output, and the first input bit (D7) is present at DOUT.
If the number of data bits entered while CS is 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 output stages is updated on the rising edge of
CS, regardless of SCLK’s state.
Diagnostic Information
The MAX4896 contains an internal output status regis-
ter used for diagnostics information for each output
(see Tables 1, 2, and 3). When a fault condition is
detected at any channel for longer than the minimum
fault-filtering time (tD(FAULT)_min), the fault information
is latched into the corresponding position in the output
status register (see Table 2), and the FLAG asserts.
Status/diagnostics data for each channel in the output
status register is transferred to the output shift register
at the falling edge of CS. While CS is low, the diagnos-
tics bits are then transferred to DOUT synchronously
with SCLK’s falling edge. A rising edge at CS resets the
output status register data. During normal operation,
the output status bit is the same as the DIN bit (DO1 =
D1, DO2 = D2). When the MAX4896 is operating with a
fault condition, the output status bit is the inverse of the
DIN bit (DO1 = 0, D1 = 1).
Detail Description
8-BIT SHIFT REGISTER
OUTPUT CONTROL REGISTER (OUT)
DOUT
OUTPUT STATUS REGISTER (OSR)
LATCHED ON CS:
LATCHED ON CS:
DIN
SCLK
CS
Figure 1. Serial Interface
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
9
Table 1. Serial-Input Address
Table 2. Serial-Output Address
DIN D0 D1 D2 D3 D4 D5 D6 D7
OUT_ OUT1 OUT2 OUT3 OUT4 OUT5 OUT6 OUT7 OUT8
DOUT DO0 DO1 DO2 DO3 DO4 DO5 DO6 DO7
OUT_ OUT1 OUT2 OUT3 OUT4 OUT5 OUT6 OUT7 OUT8
SCLK
DIN
DOUT
tCSS tCL tCH
tCSW
tCSH
tDO
tON,
tOFF
tCSO
tDS
tDH
D7 D6 D1 D0
CS
OUT_
OUTPUT
STATUS
DO_
STATUS BIT DIAGNOSTIC
Off Low Normal operation.
Off High Fault condtion. Output open or
short circuit.
On Low Fault condition. Short circuit to
positive load voltage.
On High Normal operation.
Figure 2. 3-Wire Serial-Interface Timing
Table 3. Status-Register Output Diagnostic
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
10
The minimum fault-filtering time helps mask short-dura-
tion fault conditions, such as driving highly capacitive
loads.
The typical diagnostics software routine works as follows:
• Write data to the MAX4896
• Wait for tD(FAULT) maximum to ensure diagnostics
data is ready and valid
• Write same data to the MAX4896 and read out the
diagnostics data from the shift register
Use Table 3 to diagnose the output state.
To reduce processor overhead, an interrupt-based
diagnostics routine is possible. The diagnostics routine
will analyze diagnostics data only when the FLAG out-
put triggers an interrupt.
Output Short-Circuit/Current-Limiting Protection
The MAX4896 channels (OUT_) are protected against
short-circuits conditions. When the channel’s output
current exceeds the current-limit threshold (ILIM) for
longer than the minimum fault-filtering time (tD(FAULT)
min), the short-circuit protection is activated. The short-
circuit protection behavior is determined by the logic
level at SPLD. When SPLD = high, an overloaded chan-
nel remains in a current-limited state until the short-cir-
cuit condition is removed or thermal shutdown is
reached. This allows the operation of loads where the
inrush currents may exceed the MAX4896 internal cur-
rent limit.
When SPLD = low, an overloaded channel immediately
turns off (latched-off). When a shorted output is latched
off, the channel can be turned back on after the next
serial input data is latched into the MAX4896.
Open-Load Detection
The MAX4896 features an output pulldown current
source, along with a voltage comparator, to detect an
open-load fault condition. To enable the open-load
detection function, PDCD must be low. The voltage at
OUT_ is compared with the diagnostics threshold volt-
age (VDS(OL)) to determine whether a open-load fault
condition exists.
Thermal Shutdown
If the junction temperature exceeds +160°C, all outputs
are switched off immediately (no filtering time) and
FLAG asserts. The hysteresis is approximately +20°C,
disabling thermal shutdown once the temperature
drops below +140°C.
RESET
The MAX4896 features an asynchronous reset input
that allows the user to simultaneously turn all outputs off
using a single control line. Drive RESET low to clear all
latches and registers, and to turn off all outputs. While
RESET is low, the OUT pulldown currents are disabled,
regardless of the state of PDCD.
FLAG
Output
FLAG is an open-drain latched output that can be con-
nected to a µP interrupt and pulls low whenever a fault
condition (short-circuit and/or open-load) is detected in
any of the eight outputs for longer than the minimum
fault-filtering time (tD(FAULT) min). When not using all
channels, connect unused outputs to VSthrough a
10kΩpullup resistor to avoid inadvertently triggering
the FLAG. FLAG asserts immediately, (no filtering time),
when a thermal-shutdown fault condition is detected.
The latch FLAG deasserts on CS rising edge.
Applications Information
Daisy Chaining
The MAX4896 features a digital output (DOUT) that pro-
vides a simple way to daisy chain multiple devices. This
feature allows the user to drive large banks of relays
using only a single serial interface. To daisy chain multi-
ple devices, connect all CS inputs together and con-
nect the DOUT of one device to the DIN of another
device (see Figure 3). During operation, a stream of
serial data is shifted through all the MAX4896s in
series.
Inductive Kickback Protection
Each output features an output protection clamp, limit-
ing the OUT voltage to 65V (typ). The clamp protects
against voltage transient when driving inductive loads.
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
11
MAX4896 MAX4896
DOUT
DIN
OUT1
OUT8
PGND PGNDGND
CS
SCLK
VS
VS0.1µF
CS
SCLK
DIN
DEVICE 1 DEVICE 2
DOUT
DIN
OUT1
OUT8
GND
CS
SCLK
VS
VS0.1µF
SPI/CONTROL
INTERFACE
8-BIT
LATCH
CHANNEL 1
CHANNEL 2
CHANNEL 3
CHANNEL 4
CHANNEL 5
CHANNEL 6
CHANNEL 7
CHANNEL 8
GATE CONTROL
AND CURRENT
LIMITING
OPEN / SHORT
DETECT
CLAMP
OVERTEMPERATURE
PROTECTION
DIN
DOUT
SCLK
FLAG
CS
OUT1
OUT2
OUT3
OUT4
OUT5
OUT6
OUT7
OUT8
PGNDGND
RESET
SPLDPDCDVS
MAX4896
Figure 3. Daisy-Chain Configuration
Functional Diagram
19
20
18
17
7
6
8
CS
SCLK
DOUT
9
RESET
OUT4
OUT5
OUT6
OUT3
12
OUT1
OUT2
45
15 14 12 11
VS
FLAG
OUT7
OUT8
SPLD
PDCD
MAX4896
DIN GND
3
13
16 10 PGND
PGND
*EP
TQFN
5mm x 5mm
+
TOP VIEW
*EXPOSED PADDLE. CONNECT TO PGND.
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
12
Chip Information
PROCESS: BiCMOS
Pin Configuration
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.com/packages. Note that a
“+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
PACKAGE
TYPE
PACKAGE
CODE OUTLINE NO. LAND
PATTERN NO.
20 TQFN-EP T2055+5 21-0140 90-0010
MAX4896
Space-Saving, 8-Channel Relay/Load Driver
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in
the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
13
_______________Maxim Integrated Products, Inc. 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
© 2012 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 10/05 Initial release —
1 6/07 Removal of future product notice –
2 12/07 EP clarification 7
3 7/12 Updated
FLAG
Output section 10