The LM5010Ax step-down switching regulator is an enhanced version of the LM5010 with the input operating range extended to 6-V minimum. The LM5010Ax features all the functions needed to implement a low-cost, efficient, buck regulator capable of supplying in excess of 1-A load current. This high-voltage regulator integrates an N-Channel Buck Switch, and is available in thermally enhanced 10-pin WSON and 14-pin HTSSOP packages. The constant ON-time regulation scheme requires no loop compensation resulting in fast load transient response and simplified circuit implementation. The operating frequency remains constant with line and load variations due to the inverse relationship between the input voltage and the ON-time. The valley current limit detection is set at 1.25 A. Additional features include: VCC undervoltage lockout, thermal shutdown, gate drive undervoltage lockout, and maximum duty cycle limiter.
PART NUMBER | PACKAGE | BODY SIZE (NOM) |
---|---|---|
LM5010Ax | WSON (10) | 4.00 mm × 4.00 mm |
HTSSOP (14) | 4.40 mm × 5.00 mm |
Changes from E Revision (February 2013) to F Revision
Changes from D Revision (February 2013) to E Revision
PIN | I/O | DESCRIPTION | ||
---|---|---|---|---|
NAME | WSON | HTSSOP | ||
BST | 2 | 3 | I | Boost pin for bootstrap capacitor: Connect a capacitor from SW to the BST pin. The capacitor is charged from VCC through an internal diode during the buck switch OFF-time. |
EP | — | — | — | Exposed pad |
FB | 6 | 9 | I | Voltage feedback input from the regulated output: Input to both the regulation and overvoltage comparators. The FB pin regulation level is 2.5 V. |
ISEN | 3 | 4 | I | Current sense: During the buck switch OFF-time, the inductor current flows through the internal sense resistor, and out of the ISEN pin to the free-wheeling diode. The current limit comparator keeps the buck switch off if the ISEN current exceeds 1.25 A (typical). |
NC | — | 1, 7, 8, 14 | — | No connection. Can be connected to ground plane to improve heat dissipation. |
RON/SD | 8 | 11 | I | ON-time control and shutdown: An external resistor from VIN to this pin sets the buck switch ON-time. Grounding this pin shuts down the regulator. |
RTN | 5 | 6 | — | Circuit ground: Ground return for all internal circuitry other than the current sense resistor. |
SGND | 4 | 5 | — | Sense ground: Recirculating current flows into this pin to the current sense resistor. |
SS | 7 | 10 | I | Soft start: An internal 11.5-µA current source charges the SS pin capacitor to 2.5 V to softstart the reference input of the regulation comparator. |
SW | 1 | 2 | O | Switching node: Internally connected to the buck switch source. Connect to the inductor, free-wheeling diode, and bootstrap capacitor. |
VCC | 9 | 12 | I | Output of the bias regulator: The voltage at VCC is nominally equal to VIN for VIN < 8.9 V, and regulated at 7 V for VIN > 8.9 V. Connect a 0.47-µF, or larger capacitor from VCC to ground, as close as possible to the pins. An external voltage can be applied to this pin to reduce internal dissipation if VIN is greater than 8.9 V. MOSFET body diodes clamp VCC to VIN if VCC > VIN. |
VIN | 10 | 13 | I | Input supply: Nominal input range is 6 V to 75 V. Input bypass capacitors should be located as close as possible to the VIN pin and RTN pin. |