Datasheet > A3985SLDTR-T

A3985SLDTR-T

更新时间： 2024-02-19 01:03:12

品牌	Logo	应用领域
急速微 - ALLEGRO		驱动器
页数	文件大小	规格书
15页	447K
描述
Digitally Programmable Dual Full-Bridge MOSFET Driver

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技术参数
数据手册
替代型号

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A3985SLDTR-T 技术参数

是否无铅：	不含铅	是否Rohs认证：	符合
生命周期：	Active	零件包装代码：	TSSOP
包装说明：	TSSOP,	针数：	38
Reach Compliance Code：	compliant	ECCN代码：	EAR99
HTS代码：	8542.39.00.01	风险等级：	1.56
高边驱动器：	YES	接口集成电路类型：	FULL BRIDGE BASED MOSFET DRIVER
JESD-30 代码：	R-PDSO-G38	JESD-609代码：	e3
长度：	9.7 mm	湿度敏感等级：	2
功能数量：	1	端子数量：	38
最高工作温度：	85 °C	最低工作温度：	-20 °C
标称输出峰值电流：	0.2 A	封装主体材料：	PLASTIC/EPOXY
封装代码：	TSSOP	封装形状：	RECTANGULAR
封装形式：	SMALL OUTLINE, THIN PROFILE, SHRINK PITCH	峰值回流温度（摄氏度）：	260
认证状态：	Not Qualified	座面最大高度：	1.2 mm
最大供电电压：	5.5 V	最小供电电压：	3 V
标称供电电压：	5 V	电源电压1-最大：	50 V
电源电压1-分钟：	12 V	表面贴装：	YES
温度等级：	OTHER	端子面层：	Matte Tin (Sn)
端子形式：	GULL WING	端子节距：	0.5 mm
端子位置：	DUAL	处于峰值回流温度下的最长时间：	40
宽度：	4.4 mm	Base Number Matches：	1

A3985SLDTR-T 数据手册

Digitally Programmable

Dual Full-Bridge MOSFET Driver

A3985

through the motor winding and the current sense resistor,

blanking function The blank timer is reset when PHASE is

changed.

RSENSEx. When the voltage across RSENSEx equals the

DAC output voltage, the current sense comparator resets

the PWM latch, which turns off the source MOSFET (slow

decay mode) or the sink and source MOSFETs (fast decay

mode). The maximum value of current limiting is set by the

selection of R_SENSEand the voltage at the REF input, with a

transconductance function approximated by:

The blank time can be set to 4, 6, 8, or 12 periods of the mas-

ter clock by programming the blank time bits in the Control

Dead Time To prevent cross-conduction (shoot through)

in the power full-bridge, a dead time, t_DEAD, is introduced

between switching one MOSFET off and switching the

complementary MOSFET on. The dead time, t_DEAD, is

nominally half of t_BLANK,but may be up to 1 cycle longer to

synchronize with the master clock.

I_Trip(max)= V_REF/(G_m× R_SENSE) ,

where G_mis the range factor defined by in the Data register

(Word0: Bits D17 and D18).

The DAC output reduces the VREF output to the current

sense comparator, V_DAC, in precise steps:

Mixed Decay Operation

Mixed decay is a technique that provides greater control

of phase currents while the current is decreasing. When a

stepper motor is driven at high speed, the back EMF from

the motor will lag behind the driving current. If a passive

current decay mode, such as slow decay, is used in the cur-

rent control scheme, then the motor back EMF can cause the

phase current to rise out of control. Mixed decay eliminates

this effect by putting the full-bridge initially into fast decay,

and then switching to slow decay after some time. Because

fast decay is an active (driven) decay mode, this portion of

the current decay cycle will ensure that the current remains

in control. Using fast decay for the full current decay time

(off-time, t_OFF) would result in a large ripple current, but

switching to slow decay once the current is in control will

reduce the ripple current value. The portion of the off-time

that the full-bridge has to remain in fast decay will depend

on the characteristics and the speed of the motor.

V_DAC= [(1 + DAC) × V_REF] / 64 ,

where DAC is the decimal equivalent value of the Bridge

DAC bits in the Data register (Word0: Bits D1 through D6

for Bridge 1, Bits 9 through 14 for Bridge 2). (Active codes

are represented by the values 1 through 63. Programming a

DAC input code to 0 disables the corresponding bridge, and

results in minimum load current.)

The current trip level for each DAC value then becomes:

I_TripDAC= V_DAC/(G_m× R_SENSE) .

PWM Timer Function All bridge control timing is based

on the master clock. The PWM timer is programmed via the

serial port to provide fixed off-time PWM signals to the con-

trol block. The off-time, t_OFF, is selected by programming

the Off-Time bits in the Control register (Word1, Bits D3

through D7) using the serial port. t_OFFmay be up to 1 cycle

longer than the programmed value, to synchronize with the

master clock.

When the phase current is rising, the motor back EMF does

not affect the current control, and slow decay may be used

to minimize the phase current ripple. The A3985 must be

programmed to switch between slow decay, when the cur-

rent is rising, and mixed decay, when the current is falling.

To simplify this programming sequence the decay mode is

included in the data word (Word0) with the phase current trip

level and the phase current direction.

Blanking When a source driver is turned on, a current

spike occurs due to the reverse-recovery currents of the

clamp diodes and switching transients related to distributed

capacitance in the load. To prevent false overcurrent detec-

tion due to this current spike, the output from the current

sense comparator is ignored (blanked) for a duration of time

called the blank time. The blank timer runs, when a source

power MOSFET is turned on, to provide the programmable

When mixed decay is used, the portion of the off-time that

the full-bridge remains in fast decay, t_FD, is selected by pro-

Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

www.allegromicro.com

1...6 7 8910 11 12...15

中文翻译

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A3985SLDTR-T 替代型号

型号	品牌	替代类型	描述	数据表
A3985SLD-T	ALLEGRO	功能相似	Digitally Programmable Dual Full-Bridge MOSFET Driver

与A3985SLDTR-T相关器件

型号	品牌	获取价格	描述	数据表
A3986	ALLEGRO	获取价格	Dual Full-Bridge MOSFET Driver with Microstepping Translator
A3986_12	ALLEGRO	获取价格	Dual Full-Bridge MOSFET Driver with Microstepping Translator
A3986SLD-T	ALLEGRO	获取价格	Dual Full-Bridge MOSFET Driver with Microstepping Translator
A3986SLDTR-T	ALLEGRO	获取价格	Dual Full-Bridge MOSFET Driver with Microstepping Translator
A3987	ALLEGRO	获取价格	DMOS Microstepping Driver with Translator
A3987SLP-T	ALLEGRO	获取价格	DMOS Microstepping Driver with Translator
A3987SLPTR-T	ALLEGRO	获取价格	DMOS Microstepping Driver with Translator
A3988	ALLEGRO	获取价格	Quad DMOS Full Bridge PWM Motor Driver
A3988_11	ALLEGRO	获取价格	The A3988 is a quad DMOS full-bridge driver capable of driving up to two stepper motors or
A3988SEV-T	ALLEGRO	获取价格	Quad DMOS Full Bridge PWM Motor Driver

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