Rohm BU64987GWZ Bi-directional vcm driver for auto focus Datasheet

Bi-directional VCM driver for Auto focus
BU64987GWZ
General Description
Key Specifications
The BU64987GWZ is designed to drive Bi-directional
voice coil motors. Additionally the driver is able to source
the output current without the need for a direction control
signal. The drivers include ISRC (intelligent slew rate
control) to reduce mechanical ringing to optimize the
camera’s autofocus capabilities.
Power Supply Range:
Standby Current:
Internal Resistance:
Master Clock:
Maximum Output Current:
Temperature Range:
Features








1.6V to 1.98V
0µA (Typ)
1.3Ω (Typ)
400kHz (Typ)
+100mA, -100mA (Typ)
-25°C to +85°C
Packages
1.8V Power Supply
Bi-directional Constant Current Driver
Current Source and Sink Output
10 bit Resolution Current Control
2-wire Serial Interface (I2C Fm+ compatible)
Integrated Current Sense Resistor
Power-on Reset
Thermal Shutdown Protection
W (Typ) x D (Typ) x H (Max)
UCSP30L1A
0.77mm x 1.2mm x 0.33mm
Applications
 Mobile Camera Module
 Bi-directional VCM Actuators
Typical Application Circuit
1.8V
0.1
0.1toto
10µF
10uF
VDD
VCC
1.8V
Power save
VREF
TSD
OUTPUT
Control_A
Direction
Control
&
Pre driver
SCL
I2C
master
10 bit
DAC
LOGIC
SDA
Isource
VCM MTR
OUTPUT
Control_B
Isink
Current
Sense
POR
+
-
GND
Figure 1. Typical Application Circuit
○Product structure：Silicon monolithic integrated circuit
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Pin Configuration
A1 Pin
Mark
1
2
A
GND
VDD
B
Isink
Isource
C
SDA
SCL
Figure 2. Pin Configuration (Top View)
Pin Descriptions
Pin No.
Symbol
Function
A1
GND
Ground
A2
VDD
Power supply voltage
B1
Isink
Output terminal
B2
Isource
Output terminal
C1
SDA
2-wire serial interface data input
C2
SCL
2-wire serial interface clock input
Block Diagram
VDD
Power save
VREF
TSD
OUTPUT
Control_A
SCL
LOGIC
SDA
10 bit
DAC
Direction
Control
&
Pre driver
OUTPUT
Control_B
Current
Sense
POR
Isource
Isink
+
-
GND
Figure 3. Block Diagram
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Absolute Maximum Ratings
Parameter
Symbol
Limits
Unit
Power Supply Voltage
VDD
-0.5 to +2.5
V
Control Input voltage(Note1)
VIN
-0.5 to +5.5
V
Power Dissipation
Pd
0.32(Note2)
W
Topr
-25 to +85
°C
Tjmax
125
°C
Storage Temperature Range
Tstg
-55 to +125
°C
Output Current
IOUT
+200, -200(Note3)
mA
Operating Temperature Range
Junction Temperature
(Note 1) VIN is 2-wire serial interface input pins (SCL, SDA).
(Note 2) UCSP30L1 package. Derate by 3.2 mW/°C when operating above Ta=25°C (when mounted in ROHM’s standard board).
(Note 3) Must not exceed Pd, ASO, or Tjmax of 125°C.
Caution: Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit
between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is operated over
the absolute maximum ratings.
Recommended Operating Ratings
Parameter
Symbol
Limits
Unit
Power Supply Voltage
VDD
+1.6 to +1.98
V
Control Input Voltage(Note1)
VIN
0.0 to +4.8
V
FCLK
1
MHz
IOUT
+100, -100(Note3)
mA
2-wire Serial Interface
Frequency
Output Current
(Note 1) VIN is 2-wire serial interface input pins (SCL, SDA).
(Note 3) Must not exceed Pd, ASO, or Tjmax of 125°C.
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Electrical Characteristics (Unless Otherwise Specified Ta = 25 °C, VDD = 1.8 V)
Limit
Parameter
Symbol
Unit
Min
Typ
Conditions
Max
Power Consumption
Standby Current
IDDST
-
0
5
µA
PS bit = 0, EN bit = DNC
Circuit Current 1
IDD1
-
0.9
1.5
mA
PS bit = 1, EN bit = 0
Circuit Current 2
IDD2
-
2.0
3.0
mA
PS bit = 1, EN bit = 1
Control Input (VIN = SCL, SDA)
High Level Input Voltage
VINH
1.2
-
4.8
V
Low Level Input Voltage
VINL
0
-
0.5
V
Low Level Output Voltage
VINOL
-
-
0.4
V
IIN = +3mA (SDA)
High Level Input Current
IINH
-10
-
+10
µA
Input Voltage = 0.9 x VIN
Low Level Input Current
IINL
-10
-
+10
µA
Input Voltage = 0.1 x VIN
+5
%
400kHz (Typ)
Master Clock
MCLK Frequency
MCLK
-5
-
10 Bit D/A Converter (for Controlling Output Current)
Resolution
DRES
-
10
-
bits
Differential Nonlinearity
DDNL
-1
-
+1
LSB
Integral Nonlinearity
DINL
-4
-
+4
LSB
Output Current Performance
Output Reference Current 1
IOREF1
-3
0
+3
mA
DAC_code=0x200
(Initial Value)
Output Reference Current 2
IOREF2
95
100
105
mA
DAC_code=0x3FF
Output Reference Current 3
IOREF3
-105
-100
-95
mA
DAC_code=0x000
Output Resistance
ROUT
-
1.3
1.7
Ω
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Power-up/Power-down Sequence and Function Timing Diagrams
①
②
③
④
VCC
VDD
T_reset
T_off
SCL
SCL
PS
PS
0
EN
EN
0
T_EN
Internal_EN
Internal
EN
1
0
1
0
T_EN
0
1
Target_DAC
Target
DAC
0
Target_DAC1
Target DAC
0x200
Target_DAC2
Target
DAC 2
Reference_DAC1'
Reference
DAC 1
1
Reference_DAC
Reference
DAC
0
1
0x200
( Ex. 0x300 )
Reference_DAC1
Reference
DAC 1
0x80
0x80
( Ex. 0xC0 )
Figure 4. Timing Diagram
The following commands are shown in Figure , the timing diagram:
1=Power save release, 2=Target DAC code change #1, 3=Reference DAC code change, 4=Target DAC code change #2
Table 1. Power Sequence Timing Delays
Min
Limit
Typ
Max
T_reset
20
-
-
µs
Time delay for rush current protection
T_EN
47.5
50
52.5
µs
Time delay of last 2-wire Serial Interface
command until VDD going low
T_off
1.3
-
-
µs
Parameter
Symbol
Time from VDD going high until first 2-wire
Serial Interface command
Unit
2-wire Serial BUS Format
Write mode（R/W = 0)
S
0
Output from Master
0
0
1
1
0
0
1
1
0
0
R/W
0
0
0
Output from Slave
Update
A PS EN W2 W1 W0 M D9 D8 A D7 D6 D5 D4 D3 D2 D1 D0 A
Read mode
S
0
A PS EN W2 W1 W0 M ※ ※
A
Update W (register address)
Write
S
0
0
0
1
1
0
0
1
A PS EN W2 W1 W0 M
CD9 CD8
A
CD7 CD6 CD5 CD4 CD3 CD2 CD1 CD0
A
Read
S : start signal
A : acknowledge
P : stop signal
nA : non acknowledge
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Register
Name
R/W
PS
Setting
Item
Read/Write
Setting
Serial
Power
Save
EN
Enable
W2W1W0
Register
Address
Initial
Value
Description
0 = Write to serial registers, 1 = Read from serial registers
0
0 = Driver in standby mode, 1 = Driver in operating mode
0
0 = Output current set to zero & idling current set to zero,
1 = Constant current drive
000 = Don’t care
001 = Don’t care
010 = Target position DAC code [D9:D0]
011 = Reference DAC code [D7:D0]
0
0x0
100 = Actuator resonance frequency[D7:D3], Slew rate [D1:D0]
101 = ISRC setting – point A [D9:D0]
110 = ISRC setting – point B [D9:D0]
111 = Step resolution [D7:D5], Step time[D4:D0]
M
D9 to D0
Mode
Select
Signal
10-bit Data
Setting
0 = Direct mode, 1 = ISRC or Step mode
0
0x200
10-bit data programmed to the corresponding register address
Characteristics of the SDA and SCL Bus Lines for 2-wire Serial Interface
(Ta = 25 °C, VDD = 1.6 to 1.98V)
Parameter
Symbol
STANDARDMODE(Note 4)
FAST-MODE(Note 4)
Fm+(Note 4)
Unit
Min
Max
Min
Max
Min
Max
Vhys
-
-
0.05VDD
-
0.05VDD
-
V
tSP
0
50
0
50
0
50
ns
tHD;STA
4.0
-
0.6
-
0.26
-
µs
LOW period of the SCL clock
tLOW
4.7
-
1.3
-
0.5
-
µs
High period of the SCL clock
tHIGH
4.0
-
0.6
-
0.26
-
µs
Set-up time for repeated START condition
tSU;STA
4.7
-
0.6
-
0.26
-
µs
Data hold time
tHD;DAT
0
3.45
0
0.9
0
0.45
µs
Data set-up time
tSU;DAT
250
-
100
-
50
-
ns
Set-up time for STOP condition
tSU;STO
4.0
-
0.6
-
0.26
-
µs
tBUF
4.7
-
1.3
-
0.5
-
µs
Hysterics of Schmitt trigger inputs
Pulse width of spikes which must be suppressed
by the input filter
Hold time (repeated) START condition. After this
period, the first clock pulse is generated
Bus free time between a STOP and START
condition
(Note 4) STANDARD-MODE, FAST-MODE, and FAST-MODE PLUS (Fm+) 2-wire Serial Interface devices must be able to transmit or receive at the designated speed.
The maximum bit transfer rates are 100 kbit/s for STANDARD-MODE devices, 400 kbit/s for FAST-MODE devices, and 1 Mbit/s for Fm+ devices.This transfer rates is
based on the maximum transfer rate. For example the bus is able to drive 100 kbit/s clocks with Fm+.
2-wire Serial Interface Timing
tHIGH
SCL
SCL
tHD : STA
tSU : DAT
tLOW
tSU : STA
tHD : DAT
tHD : STA
tSU : STO
SDA
SDA
tBUF
START BIT
Figure 5. Serial Data Timing
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STOP BIT
Figure 6. START and STOP Bit Timing
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Power Control
The host is able to put the driver in standby mode as well as enable/set the output to Hi-Z via 2-wire Serial Interface.
Standby mode is controlled by the PS bit and enable is controlled by the EN bit.
Please note that the PS bit is updated after the second byte is written/the second ACK from the driver is outputted during a
three byte write. The EN bit is updated after the third byte is written/the third ACK from the driver is outputted during a three
byte write. The third byte write is not required if only the standby (PS) setting is being updated.
Table 2. Power Control Register Data Format
Control Bit
Value
0
PS
1
0
1
EN
Function
Driver in standby mode
Driver in operating
mode
Driver output is Hi-Z
Driver output is enabled
Description of Output Current Characteristics
Figure 7. Description of Output Current Characteristics
The BU64987GWZ allows for configurable positive and negative output currents as well as the 0mA zero-cross reference
point (REF). The 0mA REF value is set by modifying the W[2:0]=0b011 register with an 8-bit DAC code offset by 2
LSBs. For example a REF value of 0x55 is normally shown as [0101 0101] or DEC 085, however after adding 2 zeros
to the LSB the binary value becomes [01 0101 0100] which corresponds to HEX 0x154 and DEC 340 for use in the
below equation. Based on the adjusted REF value, the maximum output current of the BU64987GWZ is calculated as:
200
𝐼𝑜𝑚𝑎𝑥 = (1023) ∗ (0𝑥3𝐹𝐹 − 𝑅𝐸𝐹)
[mA]
Equation 1. Maximum Output Current Calculation
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Additionally, based on the REF value, the minimum output current of the BU64987GWZ is calculated as:
200
𝐼𝑜𝑚𝑖𝑛 = (1023) ∗ −𝑅𝐸𝐹
[mA]
Equation 2. Minimum Output Current Calculation
Figure 8. Example of Reference Code Setting
Please note that when calculating a REF value based on a target output current, the resulting REF value needs to be
converted to an 8-bit DAC code by removing the 2 LSBs.
The reference DAC should be set based on the properties of the VCM actuator. A traditional VCM actuator uses a barrel
that rests against the mechanical end of the actuator when no current is applied to the coil. Using a traditional VCM
requires the reference DAC to be set to 0. Bidirectional VCM actuators have the natural position set based on the
actuator manufacturers’ process. Typically the reference DAC for bidirectional VCM actuators should be set so that the
output current range matches the natural full stroke range as closely as possible. The reference DAC is set to 0x80 as
a default after power initialization.
Controlling Mechanical Ringing
A VCM is an actuator technology that is intrinsically noisy due to the properties of the mechanical spring behavior. As
current passes through the VCM, the lens moves and oscillates until the system reaches a steady state. The
BU64987GWZ lens driver is able to control mechanical oscillations by using the integrated ISRC (intelligent slew rate
control) function. ISRC is operated by setting multiple control parameters that are determined by the intrinsic
characteristics of the VCM. The following illustrates how to best utilize ISRC to minimize mechanical oscillations.
Determining the Resonant Frequency of the VCM
Each VCM has a resonant frequency that can either be provided by the manufacturer or measured. The resonant
frequency of an actuator determines the amount of ringing (mechanical oscillation) experienced after the lens has been
moved to a target position and the driver output current held constant. To determine the resonant frequency, f 0, input a
target DAC code by modifying the 10-bit TDAC[9:0] value in register W[2:0] = 0b010 that will target a final lens position
approximately half of the actuator’s full stroke. Take care to not apply too much current so that the lens does not hit the
mechanical end of the actuator as this will show an incorrect resonant period. In order to start movement of the lens to the
DAC code that was set in TDAC[9:0], the EN bit must be set to 1.
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T
? ? ?
Displacement
?(µm)
µm?
0
Time
(ms)
Figure 9. Actuator Displacement Waveform (ISRC Disabled)
The resonant frequency (Hz) of the actuator can be calculated with Equation 3 using the resonant period observed in
Figure 9.
f0 = (T)-1
Equation 3. Resonant Frequency vs. Time Period Relationship
After calculating the correct resonant frequency, program the closest value in the three MSBs of the third byte of the
W[2:0] = 0b100 register using the 5-bit rf[4:0] values from Table . When calculating the resonant frequency take care
that different actuator samples’ resonant frequencies might vary slightly and that the frequency tolerance should be taken
into consideration when selecting the correct driver resonant frequency value.
Table 3. Resonant Frequency Settings
rf[4:0]
f0
rf[4:0]
0b00000
0b00001
0b00010
0b00011
0b00100
0b00101
0b00110
0b00111
50 Hz
55 Hz
60 Hz
65 Hz
70 Hz
75 Hz
80 Hz
0b01000
0b01001
0b01010
0b01011
0b01100
0b01101
0b01110
0b01111
f0
rf[4:0]
f0
rf[4:0]
f0
85 Hz
90 Hz
95 Hz
100 Hz
105 Hz
110 Hz
115 Hz
120 Hz
0b10000
0b10001
0b10010
0b10011
0b10100
0b10101
0b10110
0b10111
125 Hz
130 Hz
135 Hz
140 Hz
145 Hz
150 Hz
-
0b11000
0b11001
0b11010
0b11011
0b11100
0b11101
0b11110
0b11111
-
Selecting the Autofocus Algorithm’s Target DAC Codes
The ISRC algorithm is a proprietary technology developed to limit the ringing of an actuator by predicting the magnitude
of ringing created by an actuator and intelligently controlling the output signal of the driver to minimize the ringing effect.
Due to the ringing control behavior of ISRC, it is unable to operate properly unless the lens is floating (lens lifted off of the
mechanical end of the actuator). As such the ringing control behavior is broken into three separate operational areas in
order to provide the most optimally controlled autofocus algorithm. Please note that bidirectional VCM actuators are
inherently in a naturally floating position and as a result only the final target position is required for correct ISRC operation.
Direct Mode
ISRC Mode
Step Mode
Final target DAC
Point C
Displacement
(µm)
Bidirectional VCM
Traditional VCM
Naturally
floating
Point B
Point A
0
A: lens displacement = 0 µm
B: all lenses floating
C: final lens position
DAC code
Figure 10. Lens Displacement vs. DAC Code with a Traditional VCM Actuator
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Figure 10 illustrates the different operational modes that control the autofocus algorithm. The green line represents the
ideal operation sequence of a bidirectional VCM actuator and the red line represents the ideal operation sequence of a
conventional VCM actuator. Due to ISRC requiring a floating lens, a traditional VCM actuator (non-bidirectional) requires
points A and B to be set in order to create a floating condition. In order to simplify the code sequence, it is possible to
skip setting point A and instead only set point B, however if an optimized ringing control method is preferred, point A
corresponds to the maximum amount of current that can be applied to all VCM units without floating the lens. Point B
corresponds to the minimum amount of current that can be applied to the VCM so that all actuator units are floating. It
should be noted that the target DAC codes could vary between different actuator units and that sufficient evaluation should
be performed before selecting the point A and B target DAC codes. Point C is the final lens target position determined
by the level of focus required for the image capture and bidirectional VCM actuators only require point C for proper ISRC
operation.
The actuator manufacturer should be able to provide the required current for points A and B, however it is possible to test
these points by slowly increasing the 10-bit value of TDAC[9:0] and measuring the lens movement using a laser
displacement meter or some other device to measure lens displacement.
Output Current Control
After characterizing the VCM performance, the following should be performed in order to properly control the driver
settings for optimized autofocus performance.
Setting Point A, B, and C DAC Codes
Points A, B, and C are defined by 10-bit DAC codes set with the following registers:
Table 4. Target DAC Code Register Locations
Location
Point C
Point A
Point B
W[2:0] Register
0b010
0b101
0b110
DAC Code Location
TDAC[9:0]
ADAC[9:0]
BDAC[9:0]
Description
Final lens position before image capture
Maximum output current without floating the lens
Minimum output current required to float the lens
Please note that when the reference DAC is set to a non-zero value, due to use with a bidirectional VCM actuator, points A
and B are ignored and only point C is used for target DAC positions.
Controlling Direct Mode
Direct mode is when the driver outputs the desired amount of output current with no output current control. The time in
which the lens reaches the position that corresponds to the amount of output current set by the 10-bit DAC code is ideally
instant, ignoring the ringing effects. If the driver is set so that the lens is moved from a resting position to point C with
direct mode, ringing and settling time will be at a maximum.
Direct mode is used either when M=0 or when M=1, the reference DAC is set to 0, and the present DAC code is less than
the DAC code of point A.
M = 0 = ISRC mode disabled
When ISRC mode is disabled by setting the M bit equal to 0, the lens will traverse to the DAC code set for point C when
the EN bit is set equal to 1.
M = 1 = ISRC mode enabled
The driver automatically uses direct mode if the present DAC code is less than the target DAC code corresponding to
point A. Therefore during ISRC operation when the autofocus sequence has been started by setting the EN bit equal to
1, the driver will automatically decide to use direct mode to output current up to point A and then switch to step mode
before continuing the autofocus sequence.
Output Current (mA)
10-bit target DAC is updated and
movement starts at 3rd ACK
Time (s)
Figure 11. Direct Mode Output Current vs. Time
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Controlling Step Mode
Step mode is the control period in which the lens is moved by small output current steps. During step mode it is possible
to control the step resolution and step time in order to generate just enough output current to float the lens with minimal
ringing effects. Ringing can be better controlled by choosing a large value for the step time and a small value for the
step resolution with the trade off of a greater settling time. The step time and step resolution should be chosen depending
on the acceptable system limits of ringing vs. settling time.
Step mode is used when M=1, the reference DAC set to 0, and the present DAC code is in between point A and point B.
Typically this mode is only used during ISRC operation between point A and B, however it is possible to move the lens to
point C using only step mode if point C is set such that point C is only 1 DAC code greater than point B.
Step mode is controlled by the 5-bit step time, stt[4:0], and 3-bit step resolution, str[2:0], values stored in register W[2:0]
= 0b111. The step time is set by the 5 LSBs and the step resolution is set by the 3 MSBs of the third byte write while
using register W[2:0] = 0b111.
Table 5. Step Time Settings
stt[4:0]
Step Time
stt[4:0]
Step Time
stt[4:0]
Step Time
stt[4:0]
Step Time
0b00000
0b00001
0b00010
0b00011
0b00100
0b00101
0b00110
0b00111
50 µs
100 µs
150 µs
200 µs
250 µs
300 µs
350 µs
0b01000
0b01001
0b01010
0b01011
0b01100
0b01101
0b01110
0b01111
Table 6. Step Resolution Settings
Step
str[2:0]
str[2:0]
Resolution
0b000
0b001
0b010
0b011
1 LSB
400 µs
450 µs
500 µs
550 µs
600 µs
650 µs
700 µs
750 µs
0b10000
0b10001
0b10010
0b10011
0b10100
0b10101
0b10110
0b10111
800 µs
850 µs
900 µs
950 µs
1000 µs
1050 µs
1100 µs
1150 µs
0b11000
0b11001
0b11010
0b11011
0b11100
0b11101
0b11110
0b11111
1200 µs
1250 µs
1300 µs
1350 µs
1400 µs
1450 µs
1500 µs
1550 µs
Step
Resolution
str[2:0]
Step
Resolution
str[2:0]
Step
Resolution
2 LSB
3 LSB
0b100
0b101
4 LSB
5 LSB
0b110
0b111
6 LSB
7 LSB
The BU64987GWZ has an absolute output current range of 120mA which corresponds to a step resolution of
0.117mA/LSB.
Using a normal VCM actuator (non-bidirectional), it is possible to skip step mode during ISRC operation if a simpler
autofocus code sequence is desired. If there is no issue with moving the lens to point B using direct mode, then the
DAC code for point A should be left equal to 0. Additionally if the point A register is not set after the driver is initialized,
then the driver will automatically move the lens to point B with direct mode since the default value for point A is 0.
Controlling ISRC Mode
ISRC mode is the control period in which the lens is already floating and the driver smoothly moves the lens based on
the proprietary behavior of the ISRC algorithm. ISRC operation keeps ringing at a minimum while achieving the fastest
possible settling time based on the ISRC operational conditions.
ISRC mode is used when M=1, the reference DAC set to 0, and the present DAC code is greater than the DAC code for
point B. ISRC mode is also used when M=1 and the reference DAC set to a non-zero value. If the target DAC code
for point C is set so that the value is too large and will cause excess ringing, the point C DAC code is automatically
updated with a driver pre-determined value to minimize the ringing effect. When M=1 and the reference DAC set to 0,
the driver will automatically switch between direct mode, step mode, and ISRC mode when the point A, B, and C DAC
code conditions are met. The condition for this automatic transitioning to occur is when the register values for point B
and point C are set to values other than 0 and then the sequence will start when the EN bit is set equal to 1. Please
note that updates to point B and C DAC codes should be avoided during a focus operation in order to minimize poor
ringing effects.
C
DAC code
B
ISRC DAC codes*
ISRC mode
A
Step mode
Direct mode
※ ISRC DAC codes
– the details of ISRC
operation are
proprietary
0
Time (ms)
Start sequence
Figure 12. Three Mode Sequential Operation (Shown as DAC Codes) for Traditional VCM Actuators
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Displacement
(µm)
Bidirectional VCM
Naturally
floating
Traditional VCM
0
Time
(ms)
Sequence start point
Figure 13. Three Mode Sequential Operation (Shown as Lens Displacement)
Bidirectional VCM actuators require a non-zero reference DAC to be set. If the reference DAC is set to any value other
than 0, then the ISRC behavior will ignore point A, point B, and step mode settings and instead only use the point C final
target DAC position due to the bidirectional VCM already existing in a floating state.
Controlling the ISRC Settling Time
The settling time of an actuator is the time it takes for ringing to cease. The BU64987GWZ is able to control the settling
time by modifying the slew rate speed parameter, however care must be taken to balance settling time vs. acceptable
ringing levels. By increasing the slew rate speed there is the possibility to decrease the settling time but the ability to
control ringing is also decreased. Likewise, if less ringing is desired then there is a possibility to reduce the ringing levels
by using a slower slew rate speed setting at the cost of longer settling times. The slew rate speed can be set by modifying
the 2-bit slew_rate[1:0] value located at the 2 LSBs of register W[2:0]=0b100. Figure 4 shows the relationship of slew
rate speed vs. settling time.
? ? ?
? um?
0b11
slew_rate(1:0)=2'b11
slew_rate(1:0)=2'b10
0b10
slew_rate(1:0)=2'b01
0b01
0b00
slew_rate(1:0)=2'b00
0
Target DAC update
Time
(ms)
Figure 14. Slew Rate Speed vs. Settling Time
Table 7. Slew Rate Speed Settings
Slew Rate
slew_rate[1:0]
slew_rate[1:0]
Speed
0b00
0b01
Slowest
Slew Rate
Speed
Slow
slew_rate[1:0]
0b10
Slew Rate
Speed
Fast
slew_rate[1:0]
0b11
Slew Rate
Speed
Fastest
DAC Code Update Timing Considerations
Settling time is controlled by the resonant frequency of the actuator and the driver’s slew rate speed setting. Depending
on the combination of these parameters, the settling time can be such that updating point C with a new DAC code before
the lens has settled at the original point C DAC code can adversely affect the settling time due to increased ringing effects.
Utilize the slew rate speed parameter in order to modify the settling time so that any updates to the point C DAC code do
not occur before the lens has settled.
Please review the following example based on an actuator with a resonant frequency of 100 Hz:
Table 8. Relationship Between Slew Rate Speed and Settling Time Based on a 100Hz Actuator
Resonance Frequency f0 (Hz)
slew_rate[1:0]
Settling Time (ms)
0b00
40
0b01
24
100
0b10
16
0b11
12
In this example the settling time of the actuator can vary by up to ±5% due to the internal oscillator (MCLK) having a
variance of ±5%. The settling time has a proportionally inverse relationship to the resonant frequency and therefore the
settling time can be estimated as:
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Table 9. Relationship Between Slew Rate Speed and Settling Time Based on a General Resonant Frequency f 0'
Resonance Frequency f0’ (Hz)
slew_rate[1:0]
Settling Time (ms)
0b00
40 * (100 / f0’)
0b01
24 * (100 / f0’)
f0 ’
0b10
16 * (100 / f0’)
0b11
12 * (100 / f0’)
Note that the orientation of the camera module can affect the settling time due to the influence of gravity on the barrel.
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Register Map
Final target position, address W[2:0] = 0b010
Bit
Bit Name
Function
D0
TDAC[0]
Target position DAC code [0]
D1
TDAC[1]
Target position DAC code [1]
D2
TDAC[2]
Target position DAC code [2]
D3
TDAC[3]
Target position DAC code [3]
D4
TDAC[4]
Target position DAC code [4]
D5
TDAC[5]
Target position DAC code [5]
D6
TDAC[6]
Target position DAC code [6]
D7
TDAC[7]
Target position DAC code [7]
D8
TDAC[8]
Target position DAC code [8]
D9
TDAC[9]
Target position DAC code [9]
Reference DAC, address W[2:0] = 0b011
Bit
Bit Name
Function
D0
RDAC[0]
Reference DAC code [0]
D1
RDAC[1]
Reference DAC code [1]
D2
RDAC[2]
Reference DAC code [2]
D3
RDAC[3]
Reference DAC code [3]
D4
RDAC[4]
Reference DAC code [4]
D5
RDAC[5]
Reference DAC code [5]
D6
RDAC[6]
Reference DAC code [6]
D7
RDAC[7]
Reference DAC code [7]
D8
D9
Actuator settings, address W[2:0] = 0b100
Bit
Bit Name
Function
D0
slew_rate[0]
Slew rate [0]
D1
slew_rate[1]
Slew rate [1]
D2
D3
rf[0]
Actuator resonance frequency [0]
D4
rf[1]
Actuator resonance frequency [1]
D5
rf[2]
Actuator resonance frequency [2]
D6
rf[3]
Actuator resonance frequency [3]
D7
rf[4]
Actuator resonance frequency [4]
D8
D9
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Register Map – continued
ISRC parameter, address W[2:0] = 0b101
Bit
Bit Name
Function
D0
ADAC[0]
ISRC setting – point A [0]
D1
ADAC[1]
ISRC setting – point A [1]
D2
ADAC[2]
ISRC setting – point A [2]
D3
ADAC[3]
ISRC setting – point A [3]
D4
ADAC[4]
ISRC setting – point A [4]
D5
ADAC[5]
ISRC setting – point A [5]
D6
ADAC[6]
ISRC setting – point A [6]
D7
ADAC[7]
ISRC setting – point A [7]
D8
ADAC[8]
ISRC setting – point A [8]
D9
ADAC[9]
ISRC setting – point A [9]
ISRC Parameter, address W[2:0] = 0b110
Bit
Bit Name
D0
BDAC[0]
ISRC setting – point B [0]
Function
D1
BDAC[1]
ISRC setting – point B [1]
D2
BDAC[2]
ISRC setting – point B [2]
D3
BDAC[3]
ISRC setting – point B [3]
D4
BDAC[4]
ISRC setting – point B [4]
D5
BDAC[5]
ISRC setting – point B [5]
D6
BDAC[6]
ISRC setting – point B [6]
D7
BDAC[7]
ISRC setting – point B [7]
D8
BDAC[8]
ISRC setting – point B [8]
D9
BDAC[9]
ISRC setting – point B [9]
Step mode settings, address W[2:0] = 0b111
Bit
Bit Name
Function
D0
stt[0]
Step time [0]
D1
stt[1]
Step time [1]
D2
stt[2]
Step time [2]
D3
stt[3]
Step time [3]
D4
stt[4]
Step time [4]
D5
str[0]
Step resolution [0]
D6
str[1]
Step resolution [1]
D7
str[2]
Step resolution [2]
D8
D9
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Power Dissipation (W)
Power Dissipation
Ambient Temperature, Ta (°C)
(Reference Data)
Figure 15. Power Dissipation
I/O Equivalent Circuits
VDD
SCL
SDA
Vdd
VDD
Vdd
VDD
Vdd
VDD
SDA
SDA
SCL
SCL
GND
GND
Isource
Isink
Vdd
VDD
Vdd
VDD
Isource
Isource
Isink
Isink
Figure 16. Pin Equivalent Circuits
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Operational Notes
1. Reverse Connection of Power Supply
Connecting the power supply in reverse polarity can damage the IC. Take precautions against reverse polarity when
connecting the power supply, such as mounting an external diode between the power supply and the IC’s power supply
pins.
2. Power Supply Lines
Design the PCB layout pattern to provide low impedance supply lines. Furthermore, connect a capacitor to ground at
all power supply pins. Consider the effect of temperature and aging on the capacitance value when using electrolytic
capacitors.
3. Ground Voltage
Ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition.
4. Ground Wiring Pattern
When using both small-signal and large-current ground traces, the two ground traces should be routed separately but
connected to a single ground at the reference point of the application board to avoid fluctuations in the small-signal
ground caused by large currents. Also ensure that the ground traces of external components do not cause variations
on the ground voltage. The ground lines must be as short and thick as possible to reduce line impedance.
5. Thermal Consideration
Should by any chance the maximum junction temperature rating be exceeded the rise in temperature of the chip may
result in deterioration of the properties of the chip. In case of exceeding this absolute maximum rating, increase the
board size and copper area to prevent exceeding the maximum junction temperature rating.
6. Recommended Operating Conditions
These conditions represent a range within which the expected characteristics of the IC can be approximately obtained.
The electrical characteristics are guaranteed under the conditions of each parameter.
7. Inrush Current
When power is first supplied to the IC, it is possible that the internal logic may be unstable and inrush current may flow
instantaneously due to the internal powering sequence and delays, especially if the IC has more than one power supply.
Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing
of connections.
8. Operation Under Strong Electromagnetic Field
Operating the IC in the presence of a strong electromagnetic field may cause the IC to malfunction.
9. Testing on Application Boards
When testing the IC on an application board, connecting a capacitor directly to a low-impedance output pin may subject
the IC to stress. Always discharge capacitors completely after each process or step. The IC’s power supply should
always be turned off completely before connecting or removing it from the test setup during the inspection process. To
prevent damage from static discharge, ground the IC during assembly and use similar precautions during transport and
storage.
10. Inter-pin Short and Mounting Errors
Ensure that the direction and position are correct when mounting the IC on the PCB. Incorrect mounting may result in
damaging the IC. Avoid nearby pins being shorted to each other especially to ground, power supply and output pin.
Inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environment) and
unintentional solder bridge deposited in between pins during assembly to name a few.
11. Unused Input Pins
Input pins of an IC are often connected to the gate of a MOS transistor. The gate has extremely high impedance and
extremely low capacitance. If left unconnected, the electric field from the outside can easily charge it. The small charge
acquired in this way is enough to produce a significant effect on the conduction through the transistor and cause
unexpected operation of the IC. So unless otherwise specified, unused input pins should be connected to the power
supply or ground line.
12. Regarding the Input Pin of the IC
In the construction of this IC, P-N junctions are inevitably formed creating parasitic diodes or transistors. The operation
of these parasitic elements can result in mutual interference among circuits, operational faults, or physical damage.
Therefore, conditions which cause these parasitic elements to operate, such as applying a voltage to an input pin lower
than the ground voltage should be avoided. Furthermore, do not apply a voltage to the input pins when no power supply
voltage is applied to the IC. Even if the power supply voltage is applied, make sure that the input pins have voltages
within the values specified in the electrical characteristics of this IC.
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Operational Notes – continued
13. Ceramic Capacitor
When using a ceramic capacitor, determine a capacitance value considering the change of capacitance with
temperature and the decrease in nominal capacitance due to DC bias and others.
14. Area of Safe Operation (ASO)
Operate the IC such that the output voltage, output current, and the maximum junction temperature rating are all within
the Area of Safe Operation (ASO).
15. Thermal Shutdown Circuit(TSD)
This IC has a built-in thermal shutdown circuit that prevents heat damage to the IC. Normal operation should always
be within the IC’s maximum junction temperature rating. If however the rating is exceeded for a continued period, the
junction temperature (Tj) will rise which will activate the TSD circuit that will turn OFF all output pins. When the Tj falls
below the TSD threshold, the circuits are automatically restored to normal operation.
Note that the TSD circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under no
circumstances, should the TSD circuit be used in a set design or for any purpose other than protecting the IC from heat
damage.
16. Disturbance light
In a device where a portion of silicon is exposed to light such as in a WL-CSP, IC characteristics may be affected due
to photoelectric effect. For this reason, it is recommended to come up with countermeasures that will prevent the chip
from being exposed to light.
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Ordering Information
B
U
6
4
9
8
7
Part Number
64987
G
W
Z
Package
GWZ: UCSP30L1A
TR
Packaging and forming specification
TR: Embossed carrier tape
Marking Diagrams
Product Name
1PIN MARK
Lot No.
J7
CR
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Physical Dimension Tape and Reel Information
Package Name
UCSP30L1A(BU64987GWZ)
(Unit: mm)
< Tape and Reel Information >
Tape
Embossed carrier tape
Quantity
6,000pcs
Direction of feed
TR
The direction is the pin 1 of product is at the upper right when you
hold reel on the left hand and you pull out the tape on the right hand.
*Order quantity needs to be multiple of the minimum quantity.
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Revision History
Date
Revision
6. Oct. 2016
001
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Changes
New Release
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Notice
Precaution on using ROHM Products
1.
Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment,
OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you
(Note 1)
intend to use our Products in devices requiring extremely high reliability (such as medical equipment
, transport
equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car
accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or
serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance.
Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any
damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific
Applications.
(Note1) Medical Equipment Classification of the Specific Applications
JAPAN
USA
EU
CHINA
CLASSⅢ
CLASSⅡb
CLASSⅢ
CLASSⅢ
CLASSⅣ
CLASSⅢ
2.
ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor
products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate
safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which
a failure or malfunction of our Products may cause. The following are examples of safety measures:
[a] Installation of protection circuits or other protective devices to improve system safety
[b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure
3.
Our Products are designed and manufactured for use under standard conditions and not under any special or
extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way
responsible or liable for any damages, expenses or losses arising from the use of any ROHM’s Products under any
special or extraordinary environments or conditions. If you intend to use our Products under any special or
extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of
product performance, reliability, etc, prior to use, must be necessary:
[a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents
[b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust
[c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2,
H2S, NH3, SO2, and NO2
[d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves
[e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items
[f] Sealing or coating our Products with resin or other coating materials
[g] Use of our Products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of
flux is recommended); or Washing our Products by using water or water-soluble cleaning agents for cleaning
residue after soldering
[h] Use of the Products in places subject to dew condensation
4.
The Products are not subject to radiation-proof design.
5.
Please verify and confirm characteristics of the final or mounted products in using the Products.
6.
In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied,
confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power
exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect
product performance and reliability.
7.
De-rate Power Dissipation depending on ambient temperature. When used in sealed area, confirm that it is the use in
the range that does not exceed the maximum junction temperature.
8.
Confirm that operation temperature is within the specified range described in the product specification.
9.
ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in
this document.
Precaution for Mounting / Circuit board design
1.
When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product
performance and reliability.
2.
In principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method must
be used on a through hole mount products. If the flow soldering method is preferred on a surface-mount products,
please consult with the ROHM representative in advance.
For details, please refer to ROHM Mounting specification
Notice-PGA-E
© 2015 ROHM Co., Ltd. All rights reserved.
Rev.003
Precautions Regarding Application Examples and External Circuits
1.
If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the
characteristics of the Products and external components, including transient characteristics, as well as static
characteristics.
2.
You agree that application notes, reference designs, and associated data and information contained in this document
are presented only as guidance for Products use. Therefore, in case you use such information, you are solely
responsible for it and you must exercise your own independent verification and judgment in the use of such information
contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses
incurred by you or third parties arising from the use of such information.
Precaution for Electrostatic
This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper
caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be
applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron,
isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control).
Precaution for Storage / Transportation
1.
Product performance and soldered connections may deteriorate if the Products are stored in the places where:
[a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2
[b] the temperature or humidity exceeds those recommended by ROHM
[c] the Products are exposed to direct sunshine or condensation
[d] the Products are exposed to high Electrostatic
2.
Even under ROHM recommended storage condition, solderability of products out of recommended storage time period
may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is
exceeding the recommended storage time period.
3.
Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads
may occur due to excessive stress applied when dropping of a carton.
4.
Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of
which storage time is exceeding the recommended storage time period.
Precaution for Product Label
A two-dimensional barcode printed on ROHM Products label is for ROHM’s internal use only.
Precaution for Disposition
When disposing Products please dispose them properly using an authorized industry waste company.
Precaution for Foreign Exchange and Foreign Trade act
Since concerned goods might be fallen under listed items of export control prescribed by Foreign exchange and Foreign
trade act, please consult with ROHM in case of export.
Precaution Regarding Intellectual Property Rights
1.
All information and data including but not limited to application example contained in this document is for reference
only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any
other rights of any third party regarding such information or data.
2.
ROHM shall not have any obligations where the claims, actions or demands arising from the combination of the
Products with other articles such as components, circuits, systems or external equipment (including software).
3.
No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any
third parties with respect to the Products or the information contained in this document. Provided, however, that ROHM
will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to
manufacture or sell products containing the Products, subject to the terms and conditions herein.
Other Precaution
1.
This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM.
2.
The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written
consent of ROHM.
3.
In no event shall you use in any way whatsoever the Products and the related technical information contained in the
Products or this document for any military purposes, including but not limited to, the development of mass-destruction
weapons.
4.
The proper names of companies or products described in this document are trademarks or registered trademarks of
ROHM, its affiliated companies or third parties.
Notice-PGA-E
© 2015 ROHM Co., Ltd. All rights reserved.
Rev.003
Datasheet
General Precaution
1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents.
ROHM shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny
ROHM’s Products against warning, caution or note contained in this document.
2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior
notice. Before purchasing or using ROHM’s Products, please confirm the la test information with a ROHM sale s
representative.
3.
The information contained in this doc ument is provi ded on an “as is” basis and ROHM does not warrant that all
information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or
liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or
concerning such information.
Notice – WE
© 2015 ROHM Co., Ltd. All rights reserved.
Rev.001
Datasheet
BU64987GWZ - Web Page
Part Number
Package
Unit Quantity
Minimum Package Quantity
Packing Type
Constitution Materials List
RoHS
BU64987GWZ
UCSP30L1A
6000
6000
Taping
inquiry
Yes