MIC2185BM Micrel Inc, MIC2185BM Datasheet - Page 2

• Manufacturer Part Number: MIC2185BM
• Description: IC CTRLR PWM SYNC BOOST 16-SOIC
• Manufacturer: Micrel Inc

Specifications of MIC2185BM

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 440kHz
• Duty Cycle: 95%
• Voltage - Supply: 2.9 V ~ 14 V
• Buck: No
• Boost: Yes
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-SOIC (3.9mm Width)
• Frequency-max: 440kHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Pin Configuration
Pin Description
MIC2185
Pin Number
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
Pin Name
EN/UVLO
FREQ/2
COMP
SGND
PGND
OUTN
VREF
SYNC
OUTP
VINA
SKIP
VINP
CSH
VDD
SS
FB
16-pin Narrow Body SOIC (M)
EN/UVLO
COMP
SGND
VREF
VINA
SKIP
SS
Pin Function
Input voltage to control circuitry (2.9V to 14V).
Skip (Input): Regulator operates in PWM mode (no pulse skipping) when
pin is pulled low, and skip mode when raised to VDD. There is no automatic
switching between PWM and skip mode available on this device.
Soft Start (External Component) : Reduces the inrush current and delays
and slows the output voltage rise time. A 5µA current source will charge the
capacitor up to VDD.
Compensation (Output): Internal error amplifier output. Connect to a capaci-
tor or series RC network to compensate the regulator’s control loop.
Small Signal Ground (Return) : Must be routed separately from other
grounds to the (–) terminal of C
Feedback (Input) : Regulates FB to 1.245V.
Enable/Undervoltaqe Lockout (Input): A low level on this pin will power down
the device, reducing the quiescent current to under 0.5µA. This pin has two
separate thresholds, below 1.5V (typical) the output switching is disabled,
and below 0.9V (typical) the device is forced into a complete micropower
shutdown. The 1.5V threshold functions as an accurate undervoltage lockout
(UVLO) with 140mV hysteresis.
Voltage Reference (Output) : The 1.245V reference is available on this pin.
A 0.1µF capacitor should be connected form this pin to SGnd.
Current Sense (Input) : The (+) input to the current limit comparator. A built
in offset of 100mV (typical) between CSH and SGnd in conjunction with the
current sense resistor sets the current limit threshold level. This is also the
(+) input to the current amplifier.
3V Internal Linear-Regulator (Output) : VDD is also the supply voltage bus
for the chip. Bypass to SGND with 1µF. Maximum source current is 0.5mA.
Frequency Synchronization (Input): Connect an external clock signal to
synchronize the oscillator. Leading edge of signal above 1.4V (typical) starts
switching cycle. Connect to SGND if not used.
MOSFET Driver Power Ground (Return) : Connects bottom of current sense
resistor and the (–) terminal of C
N-Channel Drive (Output) : High current drive for n-channel MOSFET. Volt-
age swing is from ground to V
P-Channel Drive (Output) : High current drive for the synchronous p-channel
MOSFET. Voltage swing is from ground to V
5Ω.
Frequency Divider (Input) : When this pin is low, the oscillator frequency is
400KHz. When this pin is raised to VDD, the oscillator frequency is 200KHz.
Gate Drive Voltage (Input) : This is the power input to the gate drive cir-
cuitry (2.9V to 14V). This pin is typically connected to the output voltage to
enhance gate drive.
FB
16-pin QSOP (QS)
1
2
3
4
5
6
7
8
2
16 VINP
15
14
13
12
11
10
9
FREQ/2
OUTP
OUTN
PGND
SYNC
VDD
CSH
IN
OUT
P. On-resistance is typically 5Ω.
IN
.
.
IN
P. On-resistance is typically
October 2005